Ethiopian airliner down in Africa

[GordonR_Cape]

The description cited above is not an official Boeing source. I have seen not any system description from Boeing that states that MCAS will ever input nose up trim. In this way, it is not unlike what the Speed Trim System does approaching a stall when the flaps are extended.


I understand that, and cannot find an official Boeing source. But think about this scenario for one minute:
An "undocumented" maneuver augmentation system that leaves the nose trim 2.5 degrees lower than when it started.
Do you think Boeing would ever release that?
Do you think the FAA would ever certify that?
Logic dictates that your version makes no sense, for a feature which everyone agrees is not an anti-stall system.

[oggers]

I would say the MCAS trim must be reset to the original place to comply with the certification requirements. When control force is released the airspeed must return to within a small percentage of the original trim speed and also a push on the column be needed to achieve a speed below that original trim speed.

[Arydberg]

Most incidents are resolved OK but here are three other crashes where the published cause seems questionable.

https://en.wikipedia.org/wiki/Kenya_Airways_Flight_507#Investigation

https://en.wikipedia.org/wiki/Ethiopian_Airlines_Flight_409

https://en.wikipedia.org/wiki/EgyptAir_Flight_990

[Sucram]

There are a handful of skygods on here who continuously say "they should have" or "all they needed to do was" or "I would have just" and so on.

In my opinion, pilots with these outlooks are less than safe.

They have a high opinion of themselves.
They have not appreciated the HF elements of these accidents.
They have not considered how HF will affect their operation, in the event of a serious problem.
They are therefore not prepared.

If we just blame the pilots for being a bit crap, then nothing in the industry will improve. We need to understand why these pilots, despite all of their efforts, could not keep the aircraft from the ground. Only when we understand, can we make the correct changes to stop it happening again.

Even the finest pilots in the world, when suddenly presented with a simple failure (double engine failure, for example), will sit there and think "no - this can't be happening" followed by "what on earth do I do".

It is inexcusable that Boeing and the FAA allowed a pretty ropy old aircraft with some dodgy characteristics to be released with even poorer characteristics. It is a demonstration of how multiple signals during a critical phase of flight can make it very difficult for pilots to overcome startle, then diagnose, fly and solve a problem.

As an aside - in my airline it was discovered that UAS events were handled badly. So in one sim cycle we were trained. In the next sim cycle we were tested, and still it was handled badly. So in the next sim cycle again we were trained a lot more. It transpires that real UAS is really a HF event of great complexity, and is therefore very difficult to get right. The technical side of it is a doddle.

Can we please focus on how we contribute to make the industry better (safer)?
Well said, totally agree

[737 Driver]

Interestingly, on this forum, pilots seem to blame the Max pilots for not flying their planes, while engineers blame the design and the process. Quite possibly both are correct.


You are correct, sir.

Aircraft accidents are rarely the result of a single cause. In this case, we have a failure in the initial design process, a failure in the internal (Boeing) review process, a failure in the oversight process (FAA and other certifications authorities), a failure in the education and training process (airlines, Boeing, certifications authorities), and at least one documented failure in the maintenance process (Lion Air). However, despite all these numerous failures, the aircraft in question were still flyable by reverting to basic airmanship techniques of pitch, power, and trim. Yet here we are.

I am not an engineer, so I don’t have the background to say exactly how the engineers went wrong, even though I know they did. I am not a project manager or regulator, so I don’t have the expertise to say exactly how they erred. I am not a maintenance technician, so I am not qualified to comment on where their process went wrong. I’m a little closer to the airline training environment, so I feel I can comment on how they could have handled this better.

However, I most certainly am a 737 type-rated Captain who is given the responsibility of saving the lives of my passengers when everyone else fails to do their job. Even at my airline, our training should be better, our manuals should be better, our maintenance procedures should be better, and our scheduling practices should be better, but the reality is that they are not. I do not have the leisure to say that if all these other people don’t do their job right, I don’t have to do mine. My job, when everything goes to $hit, is to do everything in my power to stabilize the aircraft and get it safely back on the ground. If I don’t, then that is on me.

[737 Driver]

I understand that, and cannot find an official Boeing source. But think about this scenario for one minute:
An "undocumented" maneuver augmentation system that leaves the nose trim 2.5 degrees lower than when it started.
Do you think Boeing would ever release that?
Do you think the FAA would ever certify that?
Logic dictates that your version makes no sense, for a feature which everyone agrees is not an anti-stall system.

I’m not trying to argue logic or whatever Boeing and FAA should have done. Obviously, the MCAS design was flawed. I am simply reporting what has been officially stated about how this system actually works.

For non-pilots, it may be difficult to relate to the dynamic environment of an approach to stall and recovery maneuver. The going in assumption is that the pilots would not intentionally place the aircraft close to the stall. When an approach to stall is detected, various aircraft systems kick in to both provide warning and assistance. However, it is also assumed that once alerted to the stall, the pilots will disengage the automation and hand-fly the aircraft back to a safe airspeed and altitude. This maneuver involves the same things I keep referring to - pitch, power, and trim. I can only speak for the aircraft I have flown, and not a single one of them was designed for the automation to execute the stall recovery. Assist, yes. Execute, no.

[MD80767 Driver]

You are correct, sir.

Aircraft accidents are rarely the result of a single cause. In this case, we have a failure in the initial design process, a failure in the internal (Boeing) review process, a failure in the oversight process (FAA and other certifications authorities), a failure in the education and training process (airlines, Boeing, certifications authorities), and at least one documented failure in the maintenance process (Lion Air). However, despite all these numerous failures, the aircraft in question were still flyable by reverting to basic airmanship techniques of pitch, power, and trim. Yet here we are.

I am not an engineer, so I don’t have the background to say exactly how the engineers went wrong, even though I know they did. I am not a project manager or regulator, so I don’t have the expertise to say exactly how they erred. I am not a maintenance technician, so I am not qualified to comment on where their process went wrong. I’m a little closer to the airline training environment, so I feel I can comment on how they could have handled this better.

However, I most certainly am a 737 type-rated Captain who is given the responsibility of saving the lives of my passengers when everyone else fails to do their job. Even at my airline, our training should be better, our manuals should be better, our maintenance procedures should be better, and our scheduling practices should be better, but the reality is that they are not. I do not have the leisure to say that if all these other people don’t do their job right, I don’t have to do mine. My job, when everything goes to $hit, is to do everything in my power to stabilize the aircraft and get it safely back on the ground. If I don’t, then that is on me.

As I'm sure the Lion Air and Ethiopian pilots did ! None of them wanted to die. None of them gave up until hitting the ground. So, what is your point ??

[olster]

I think the point (presumably) he is trying to make is that he would not have crashed due to superior flying skill. Basically rubbish of course.

[oggers]

Even the finest pilots in the world, when suddenly presented with a simple failure (double engine failure, for example), will sit there and think "no - this can't be happening" followed by "what on earth do I do".

Half right in the case of Cactus 1549. 'The physiological reaction was strong and I had to use training to force calm on the situation. I was sure I could do it' said Capt Sullenberger.

The 'finest pilots in the world' are probably amongst the best trained pilots in the world. Good training undoubtedly makes a difference to outcomes.

[737 Driver]

As I'm sure the Lion Air and Ethiopian pilots did ! None of them wanted to die. None of them gave up until hitting the ground. So, what is your point ??

Is it also your position that the engineers did everything they could do? The MAX program managers? Boeing? The regulators? The airlines and their training departments? Did all these people simply meet expectations? Do we just sit idly by and say, “That’s okay, I’m sure you did your best” ?!

The responsibility for these accidents should be shared broadly, but the pilots are almost always the first ones to the scene of the accident. Sometimes we cannot simply accept a certain level of training and skills because we passed the minimum standards of a training department whose primary allegiance is to an organization that wants to keep the metal moving at a minimum cost.

The point is to learn not only from our mistakes, but also the mistakes of others. No, I don’t think anyone intended for hundreds of people to die, but die they did. Every specialty that touched these accidents ought to be doing a lot of soul searching and asking themselves how they could have done better.

As far as the flight crew, no one was expecting them to come up with some innovative split-s, half-barrel roll maneuver to save this aircraft. All that was required of the flying pilot was to recognize the immediate problem, execute the first steps of what should have been a well-known procedure, keep his thumb near the yoke trim switch, and simply trim the stab as necessary. Turn off the magic, pitch 10 degrees, power to 80% and trim. That's it! This is not test pilot territory.

Have our expectations of what constitutes basic airmanship skills for a commercial airline pilot fallen so low?

[GordonR_Cape]

I’m not trying to argue logic or whatever Boeing and FAA should have done. Obviously, the MCAS design was flawed. I am simply reporting what has been officially stated about how this system actually works.
For non-pilots, it may be difficult to relate to the dynamic environment of an approach to stall and recovery maneuver. The going in assumption is that the pilots would not intentionally place the aircraft close to the stall. When an approach to stall is detected, various aircraft systems kick in to both provide warning and assistance. However, it is also assumed that once alerted to the stall, the pilots will disengage the automation and hand-fly the aircraft back to a safe airspeed and altitude. This maneuver involves the same things I keep referring to - pitch, power, and trim. I can only speak for the aircraft I have flown, and not a single one of them was designed for the automation to execute the stall recovery. Assist, yes. Execute, no.




I half-understand your confusions, because to the best of our knowledge, no MCAS system has engaged and then rolled back the elevator trim. In the three cases we do know about, one was disconnected and flown entirely manually, the other two were irreversible due to stuck AOA data.

Edit: It just occurred to me that perhaps one of the reasons that Boeing has been coy about the unwinding of the trim, has been a legal one. Making a clear statement that MCAS was designed to unwind trim, when it did not do so in two crashes, could be a slam-dunk for product liability. Safer to obfuscate and clarify later, once its properly fixed!?

Part of your statement is a non-sequitur: I do not know of any situation in which an autopilot will bring an aircraft close to a stall. The whole point of MCAS is that it is for a rarely used situation in which the aircraft is already under manual control, and the pilot needs assistance to carry out maneuvers at high AOA, but below the stall condition.

My observation is that nobody has bothered to document the unwinding of the MCAS trim, because it has never happened, and if it did the effects would be relatively benign. This is implicit in the relatively low hazard classification, and the fact that no additional pilot training was needed for MCAS certification by the FAA.

I am not a pilot, but it astonishes me that some well informed members (not just you), can be so fundamentally misinformed about the specific details of MCAS operation. No wonder Boeing didn't try to explain it the first time!?

Re-posting the AOA chart first posted by LEOCh in: https://www.pprune.org/10423226-post260.html

Edit: Also refer to the detailed description by FCeng84 in: https://www.pprune.org/10430828-post2589.html

https://cimg4.ibsrv.net/gimg/pprune.org-vbulletin/782x523/737max_42ba748ff04066af5c42a57f1265dc0bd62f9898_e26a3eb36bd2 c2d8c0a62cc2d14fc6fa5be6c072.jpg

[737 Driver]

I am not a pilot, but it astonishes me that some well informed members (not just you), can be so fundamentally misinformed about the specific details of MCAS operation. No wonder Boeing didn't try to explain it the first time.

When I first got into this business, our manuals used to be far more detailed. We used to say we could just about build the aircraft with the information they gave us. Nowadays, not so much. Someone decided that we pilots didn’t need all the technical details, but rather only the procedures. I’m not in that camp, but no one asked me. If not for these accidents any information that Boeing would have provided the pilots on MCAS would have been just as generic as the information they currently give us on the Speed Trim and Elevator Feel Systems (both of which are also activated in a stall).

But in regards to MCAS, I will simply repeat that Boeing has provided no information that would lead me to believe that it would ever unwind any nose down input. This behavior is entirely consistent with how the Speed Trim behaves in a stall situation, so I think you are looking for something that is not there. I am happy to stand corrected if Boeing every publishes new information to the contrary.

[hawk76]

Re-posting the AOA chart first posted by LEOCh


Remember, though, this chart was schematic in nature and speculated on what the graph might look like, to illustrate a point about what MCAS was likely doing to achieve its goal. I could be wrong, but I don't think anyone posted an actual plot for the MAX. Still, it is well-informed speculation and to me illustrates the point. And FCeng84's posts on the topic have been particularly enlightening; anyone looking to catch up should search for these.

[GordonR_Cape]

Remember, though, this chart was schematic in nature and speculated on what the graph might look like, to illustrate a point about what MCAS was likely doing to achieve its goal. I could be wrong, but I don't think anyone posted an actual plot for the MAX. Still, it is well-informed speculation and to me illustrates the point. And FCeng84's posts on the topic have been particularly enlightening; anyone looking to catch up should search for these.

Point taken, partly speculation about how it should work! However if you were designing a system that could apply MCAS repeatedly, then unwinding trim would be the first step. Otherwise there would be a high probability of ending up in an irreversible nose-down trim situation, following a series of repeated nose up elevator inputs (even with a functioning AOA sensor). Even the greenest system engineer or programmer would have picked up that issue, though not the more subtle case of stuck AOA data (which everyone focuses on).

It seems likely that most of these documents are under legal lock-down, so we may not know the truth for some time. Equally likely is that when the revised MCAS is certified, the details will be better documented. Either way, there will probably be some degree of training implications.

[SamYeager]

I completely agree with your post. The fact that the day before the Lionair crash another crew flew on safely and landed, to be able to write up the defect, speaks volumes.

Supposedly this first crew might well have been amongst the first victims if they hadn't been lucky enough to have a jump seater to point them into the right direction if the rumours are true. Your logic may be suspect.....

[PerPurumTonantes]

Interestingly, on this forum, pilots seem to blame the Max pilots for not flying their planes, while engineers blame the design and the process. Quite possibly both are correct.
I'm an engineer and a pilot. The responsibility is with Boeing/FAA, no question. Yes the ET302 crew could have done a few things different. But they had 6 minutes. In a little box in the sky, where the wrong answer meant death, with alarms going off, and not just useful alarms but alarms telling them to do the opposite of what they needed.

You train pilots to trust in safety systems, trust in automation, follow the checklists, follow the SOPs. They do this every day successfully for years. Then you expect them to instantly drop this and distrust all the safety systems and automation, work out which one is faulty and what to do about it, while simultaneously hand flying an aircraft that's behaving like they have never experienced before in any of the hand flying they've done.

Boeing had plenty of time, in nice safe offices that weren't about to crash into the ground, to get this right.

[OldnGrounded]

I think the point (presumably) he is trying to make is that he would not have crashed due to superior flying skill. Basically rubbish of course.

Yes. We have some pilots here who are quite certain that, "It wouldn't have happened to me." This, in the face of what are now mountains of evidence suggesting that it could easily have happened to anyone. Confidence is a good thing for professionals to have. Arrogant over-confidence is scary and dangerous.

[alf5071h]

Icarus2000 https://www.pprune.org/10454286-post4255.html
‘The fact that the day before … another crew flew on safely and landed …’

#4287 ‘Your logic may be suspect.....’ :ok:
The outcome of an event does not alter the risk that existed before the event, nor without mitigation, the future risk.
Just because flights land safely every day does not remove the risk from flying; if thought otherwise then aviation is best be avoided.

[ATC Watcher]

They have not considered how HF will affect their operation, in the event of a serious problem.
They are therefore not prepared.

If we just blame the pilots for being a bit crap, then nothing in the industry will improve.
Can we please focus on how we contribute to make the industry better (safer)?
Very well said ! Glad to see some common sense coming back and shifting the discussion to at least half the problem in both these accidents : human factors.
Training on a simulator for abnormal situations to create automatism works well, but not everybody will react the same way when confronted with the REAL emergency.

For instance how do you explain how a 55 years old captain with 16.000h assisted with an FE with 19.500h can reject a take off after V1 (and even VR ) contrary to all SOPs and maybe dozens and dozens of SIM sessions ?
This happened in 1982 with a DC10 , and in that era , incident investigations reports had 20+ pages on human factors . The aim was to understand what went in the head of the captain in order to make the system better not blaming individuals .
PPRuNe did not exist in 1982, but I am sure it it had, there would have been thousands of posts blaming the crew. but the reports says differently..

The report of that accident is on line if you have time to spare, the HF part is very good. : Malaga DC10 1982 (http://www.fomento.es/NR/rdonlyres/24451F6D-3AC8-40F0-8D74-F611D46EF39C/14154/1982_031_A_Spantax_English1.pdf)

[hec7or]

I do not know of any situation in which an autopilot will bring an aircraft close to a stall.

Try mountain wave at high altitude

I am not a pilot

quite

[Water pilot]

When I first got into this business, our manuals used to be far more detailed. We used to say we could just about build the aircraft with the information they gave us. Nowadays, not so much. Someone decided that we pilots didn’t need all the technical details, but rather only the procedures. I’m not in that camp, but no one asked me. If not for these accidents any information that Boeing would have provided the pilots on MCAS would have been just as generic as the information they currently give us on the Speed Trim and Elevator Feel Systems (both of which are also activated in a stall).

But in regards to MCAS, I will simply repeat that Boeing has provided no information that would lead me to believe that it would ever unwind any nose down input. This behavior is entirely consistent with how the Speed Trim behaves in a stall situation, so I think you are looking for something that is not there. I am happy to stand corrected if Boeing every publishes new information to the contrary.
Well, given that they didn't even tell you about the system in the first place, I would be a little reluctant to conclude that they have told you everything about it now. However, I certainly hope that by the time the plane is certified again pilots will know more about MCAS than the project managers at Boeing knew during design.

This really has the feel of the sort of thing I have been unfortunately involved in (not aviation), the "we aren't exactly going to lie about this but it raises uncomfortable questions so let's hide it under the rug" patch to save the project once the company is committed to a course that in retrospect was not the best solution to the problem. Engineers realize that if they talk about it too much they are going to be tasked with updating the copyright notices on 10,000,000 lines of code and baby-sitting the 3a.m. builds. The cynical ones accept it because the project is so %#@!! already that it doesn't stand a chance of working anyway.

That sort of mentality takes a long time to get over and I still feel some of that energy coming from Chicago. What exactly "minor control surface" issues were also fixed in this latest patch?

The good news to a Boeing supporter on the horizon is that they are writing off $1 billion for the repair (supposedly not liability) which to me sounds as if it is more than a 1/2 hour software upgrade. That sort of money sounds like a hardware fix, which is what I think they need.

[hawk76]

If we just blame the pilots for being a bit crap, then nothing in the industry will improve. We need to understand why these pilots, despite all of their efforts, could not keep the aircraft from the ground. Only when we understand, can we make the correct changes to stop it happening again.

If we just blame Boeing for being a bit crap, and ignore pilots, then nothing will improve, either.

Can we please focus on how we contribute to make the industry better (safer)?
I think that is what we're trying to do. It's not clear to me why the fault has to be all Boeing or all pilot. Why some say that as soon as the AOA vane went, the plane was doomed. To me both pilot and plane have some fault, and to be fair, part of that fault on the pilots may be due to insufficient training. But let's consider all possibilities without making offensive ad hominem arguments seen in a lot of posts on this thread. Then we may have the better understanding you mention.

[737 Driver]

Originally Posted by GordonR_Cape https://www.pprune.org/images/buttons/viewpost.gif (https://www.pprune.org/rumours-news/619272-ethiopian-airliner-down-africa-215.html#post10454675)
I do not know of any situation in which an autopilot will bring an aircraft close to a stall.​​​​​​

Also any flight with the autothrottles on placard.

[PerPurumTonantes]

The notable exception was AF447 - loss of airspeed, confusing alerts, systems reacting in ways the pilot flying wasn’t expecting, improper crew response, followed by a hull loss and major loss of life. This was another clear example of the pilots’ failure to revert to basics and fly the aircraft. Their ethnicity or employment at a major European carrier granted them no special protection from a failure of airmanship.



AF447 is not really comparable. The aircraft did not actively try to kill them. The AF447 crew's actions were less competent than the ET302 crew. Continuous back pressure stalling the a/c all the way down?

AF447 crew crashed the aircraft (with a bit of help from Airbus' sidestick design). Whereas ET302 the aircraft crashed itself despite the crew's efforts.

[michaelbinary]

All the armchair pilots giving it large, they should have done this or that or the other are talking crap.
This whole thing was about money and how to spend as little as possible.
Boeing producing an aircraft not fit or safe to fly without extra added systems to correct the inherent pitch instability.
Boeing for not telling about or training the pilots what MCAS was or did and how to defeat it.
Boeing for not designing any redundancy into the system or cross checking with other systems.
Boeing for not testing the system and/or the software that controlled it properly or extensively enough to cover all eventualities
Boeing for not having a bloody OFF switch that allowed the pilots to fly the plane when all else fails.
FAA for being complicit in allowing Boeing to self certify an aircraft (WTF ?)
US Government for being complicit in allowing FAA and Boeing to act that way.

All these organisations should be completely ashamed of themselves, there was nothing wrong with the aircraft at all, but the computers didn't allow the pilots to fly it.
I hope Boeing, gets the arse sued out of it, by everybody, they deserve it.

Now for all those clever dicks on here who think the pilots should have done this or that or the other. I reckon from reports, the plane was around 9000 ft AMSL which is about 1342 ft AGL. In that time an object in free fall will take about 9 seconds to hit the ground. So before you finished reading the third line of this post you would be dead. Good luck in fixing a problem in a system you were not trained on or even told about.

[MurphyWasRight]

All the armchair pilots giving it large, they should have done this or that or the other are talking crap.
This whole thing was about money and how to spend as little as possible.
Boeing producing an aircraft not fit or safe to fly without extra added systems to correct the inherent pitch instability.
Boeing for not telling about or training the pilots what MCAS was or did and how to defeat it.
Boeing for not designing any redundancy into the system or cross checking with other systems.
Boeing for not testing the system and/or the software that controlled it properly or extensively enough to cover all eventualities
Boeing for not having a bloody OFF switch that allowed the pilots to fly the plane when all else fails.
FAA for being complicit in allowing Boeing to self certify an aircraft (WTF ?)
US Government for being complicit in allowing FAA and Boeing to act that way.

.
A few more for the mix:
Boeing for minimizing the changes in the emergency AD to keep the "covered by existing procedures" and 'just like NG" myths alive..
Boeing for REMOVING the OFF switch, 737 NG right hand trim cutout of automation only, MAX either switches cut all electric trim.
Boeing/others? for removing training on unloading to allow manual trim when severely out of trim. (roller coaster)
Boeing for providing an emergency backup manual trim system that could not be operated under some out of trim conditions.

Penultimate Lion Air pilots for the as yet unexplained minimal write up that led to AoA sensor not diagnosed/corrected.

Unknown at this point cause of Lion Air sensor reading 20 degrees offset not detect during post instal testing.

As some have suggested it is possible that ET crew awareness of MCAS may have been a factor, impossible to say of course what would have happened had they been the first to experience this.

[Bend alot]

Also MCAS was documented at 0.6 for certification, but in reality is it was 2.5.

[Water pilot]

Penultimate Lion Air pilots for the as yet unexplained minimal write up that led to AoA sensor not diagnosed/corrected.
.
I thought that the sensor had been replaced before the fatal flight, or am I mistaken? My understanding is that there are three failed sensors, not necessarily for the same reason.

[Water pilot]

Boeing still does not get it.

Boeing CEO denies any 'technical slip' in 737 MAX crashes (https://www.seattletimes.com/business/boeing-aerospace/737-max-grounding-cuts-into-boeing-sales-and-cash-reserves/)

Boeing chief Dennis Muilenburg denied Wednesday that the two recent crashes of the 737 MAX were due to any “technical slip” by Boeing during the jet’s design or certification.

Muilenburg conceded that erroneous information was fed to the airplanes on both flights by a faulty sensor on the fuselage, and that this false signal activated a new flight-control system on the MAX that repeatedly pushed the jet’s nose down.

Still, he adamantly denied that any fault in the design led to the deaths of the 346 people aboard the two planes.

“There is no technical slip or gap here,” Muilenburg said on an early morning conference call with Wall Street analysts following release of Boeing’s first-quarter earnings. “We understand our airplane. We understand how the design was accomplished, how the certification was accomplished, and remain fully confident in the product.”


So they understood that a single failure of a sensor would cause the plane to pitch nose down shortly after takeoff and they did not feel that it was necessary to inform pilots of this quirk? The words "reckless disregard" come to mind.

I understand that the CEO is trying to walk the line between what he wants to say for the lawyers (" not our fault, just a coincidence that two horrible pilots crashed our new design plane") and what he wants to say for customers ("we are on it, figured out the problem and now we have it fixed") but in my opinion he is failing as badly as the engineers. Liability for the two crashes is the least of Boeing's concerns at this point. Statements like this do not give me confidence that they are really interested in finding and fixing the fault, since they do not want to admit that there is one.

[Icarus2001]

Yes the ET302 crew could have done a few things different. But they had 6 minutes No, the six minutes was the result. Had the PF used electric trim ANU they could have had as much time as they wanted to try a memory item, like turning off the trim system.
Some aircraft do not have a manual trim wheel, this one does. Get the trim somewhere near correct with the electric trim switch and then turn off the trim. As 737 Driver keeps saying, this is not test pilot territory. It is basic flying skills, trim away the pressure.

[Bend alot]

Get the trim somewhere near correct with the electric trim switch and then turn off the trim. As 737 Driver keeps saying, this is not test pilot territory. It is basic flying skills, trim away the pressure.

"Get the trim somewhere near correct with the electric trim switch and then turn off the trim." - Perfect wording to have put in that AD! - yet there is the "no problem here" attitude that prevented such a simple wording.

Instead it was something like revert to previous check lists and procedures. (but some of you will not know AoA disagree - just to complicate things a bit more)

I think that actually and technically once MCAS is switched off certain areas of flight within the flight envelope are actually in "test pilot territory" as certification standards are not meet.

Around post # 330 there seems a pilot has used the MAX sim and the impression is - basic flying skills are very much challenged in the simulated event.

[DaveReidUK]

I thought that the sensor had been replaced before the fatal flight, or am I mistaken?

Yes, you are correct.

My understanding is that there are three failed sensors, not necessarily for the same reason.

We don't know that. There was an inconclusive discussion over in Tech Log a few weeks ago (https://www.pprune.org/tech-log/616624-maintenance-lapse-identified-initial-problem-leading-lion-air-crash-5.html) - the consensus appears to be that there has so far been no information published on whether the removed sensor was found to be faulty on the bench or, if it was, what the precise nature of the problem was.

That, in itself, is very odd. If anyone knows more, please share.

[MurphyWasRight]

Originally Posted by Water pilot https://www.pprune.org/images/buttons/viewpost.gif (https://www.pprune.org/showthread.php?p=10455133#post10455133)
I thought that the sensor had been replaced before the fatal flight, or am I mistaken?
Yes, you are correct. My understanding is that there are three failed sensors, not necessarily for the same reason. We don't know that. There was an inconclusive discussion over in Tech Log a few weeks ago (https://www.pprune.org/tech-log/616624-maintenance-lapse-identified-initial-problem-leading-lion-air-crash-5.html) - the consensus appears to be that there has so far been no information published on whether the removed sensor was found to be faulty on the bench or, if it was, what the precise nature of the problem was.

That, in itself, is very odd. If anyone knows more, please share. The sensor was replaced before the penultimate flight and was ~20 degrres off for both flights according to the preliminary report.
The original replacement was due to intermittent problems that could have been the sensor or other things such as flaky connector.

[737 Driver]

So they understood that a single failure of a sensor would cause the plane to pitch nose down shortly after takeoff and they did not feel that it was necessary to inform pilots of this quirk?

First, I'm not defending Boeing here, but I would like to add in some background regarding 737 system design that might shed some light how the Boeing design team might have overlooked the significance of the single sensor failure issue with MCAS.

The 737 has a number of warning and assist systems that activate when an approach to stall is detected. Determination of the approach to stall condition is accomplished by the Stall Management Yaw Damper (SYMD) computer and the Air Data Inertial Reference Unit (ADIRU) using inputs from various sensors to include the AOA vane and pitot-static system. (There is also a completely independent and uncompensated standby attitude/airspeed/altitude instrument on the center forward instrument panel, but it does not generate any warnings.)

The SYMD's and ADIRU's work independently, although divergent outputs can generate specific warnings like IAS Disagree and ALT Disagree. Each side can independently generate a stall signal. This is a conservative approach since it is better to receive a stall signal when you are not in a stall (false positive) than to receive none when you are (false negative).

When a stall signal is generated, a number of systems can activate to provide warning and assistance to the pilot in the subsequent stall recovery - Stick Shaker, Elevator Feel Shift, Speed Trim Stall ID function, Autoslats, and reduced Yaw Damper input. The important point here is that it only takes one stall signal (possibly erroneous) to activate these systems. While erroneous activation of these systems is an annoyance, they are not existential threats.

In terms of design philosophy, MCAS was no different than these other stall-related systems. If fact, in at least one Boeing document MCAS is referred to as a sub-function of the Speed Trim System (STS) and MCAS responds to a stall in almost the exact same manner as the STS does currently.

With one important difference, and that difference was crucial.

First of all, some of you might be surprised to learn that in a stall condition, the STS will trim the stab nose down at the exact same speed as MCAS and can do so continuously until it hits the stop. This is far more authority than MCAS ever had. Why is not a problem? Because the STS will respect the control column trim cutout switches. These are not the pedestal switches that are activated by the pilot. These limit switches are located at the base of the control column and prevent trimming opposite the direction of column displacement. That is, if a pilot is pulling back on the yoke, then nose down trim is inhibited. If someone is pushing forward on the yoke, nose up trim is inhibited. Thus the authority of STS is limited by the control inputs of the pilot.

Because MCAS was needed to activate during an accelerated stall (i.e. turning, nose low recovery), this system was designed to bypass the aft control column cutout switch. Someone at Boeing did not connect the dots and realize that by removing this important barrier, it now created a new threat in the case of an erroneous stall signal.

I'll speculate here that since the folks at Boeing apparently considered MCAS to merely be an additional function of the existing STS, no further education was required.

Obviously, they were wrong and now everyone is powerfully aware of the significance of this oversight.

[GordonR_Cape]

First, I'm not defending Boeing here, but I would like to add in some background regarding 737 system design that might shed some light how the Boeing design team overlooked the significance of the single sensor failure issue with MCAS.

The 737 has a number of warning and assist systems that activate when an approach to stall is detected. Determination of the approach to stall condition is accomplished by the Stall Management Yaw Damper (SYMD) computer and the Air Data Inertial Reference Unit (ADIRU) using inputs from various sensors to include the AOA vane and pitot-static system. (There is also a completely independent and uncompensated standby attitude/airspeed/altitude instrument on the center forward instrument panel, but it does not generate any warnings.)

The SYMD's and ADIRU's work independently, although divergent outputs can generate specific warnings like IAS Disagree and ALT Disagree. Each side can independently generate a stall signal. This is a conservative approach since it is better to receive a stall signal when you are not in a stall (false positive) than to receive none when you are (false negative).

When a stall signal is generated, a number of systems can activate to provide warning and assistance to the pilot in the subsequent stall recovery - Stick Shaker, Elevator Feel Shift, Speed Trim Stall ID function, Autoslats, and reduced Yaw Damper input. The important point here is that it only takes one stall signal (possibly erroneous) to activate these systems. While erroneous activation of these systems is an annoyance, they are not existential threats.

In terms of design philosophy, MCAS was no different than these other stall-related systems. If fact, in at least one Boeing document MCAS is referred to as a sub-function of the Speed Trim System (STS) and MCAS responds to a stall in almost the exact same manner as the STS does currently.

With one important difference, and that difference was crucial.

First of all, some of you might be surprised to learn that in a stall condition, the STS will trim the stab nose down at the exact same speed as MCAS and can do so continuously until it hits the stop. This is far more authority than MCAS ever had. Why is not a problem? Because the STS will respect the control column trim cutout switches. These are not the pedestal switches that are activated by the pilot. These limit switches are located at the base of the control column and prevent trimming opposite the direction of column displacement. That is, if a pilot is pulling back on the yoke, then nose down trim is inhibited. If someone is pushing forward on the yoke, nose up trim is inhibited. Thus the authority of STS is limited by the control inputs of the pilot.

Because MCAS was needed to activate during an accelerated stall (i.e. turning, nose low recovery), this system was designed to bypass the aft control column cutout switch. Someone at Boeing did not connect the dots and realize that by removing this important barrier, it now created a new threat in the case of an erroneous stall signal.

I'll speculate here that since the folks at Boeing apparently considered MCAS to merely be an additional function of the existing STS, no further education was required.

Obviously, they were wrong.

Thanks for re-stating the background, and many important points. Much of that material has previously been posted posted on this forum, including the Lion Air thread (many months ago). An important point not often discussed, was whether any of those other systems were operating at the same time as MCAS and stick shaker. The answer is they were probably inhibited, based on the known FDR readouts, and the likely control column inputs.

Your version is plausible on many levels, but IMO fails at several hurdles. These may be due to differences in definitions:
- MCAS was never intended to be an anti-stall system (rather it has to do with longitudinal stability and stick forces).
- MCAS was designed to activate at a much lower AOA, independent of the stick shaker.
- MCAS was designed to activate under many areas of the flight envelope, independent of the stick forces and airspeed.
- Disabling the control column cutout switches was intentionally added to MCAS, but was not its sole function or scope.

It has been mentioned before, but there seems to be no clarity if MCAS was intended to continue operating during an actual stall/stick shaker event, or only during the initial high AOA condition preceding the stick shaker/stall warning. The new version will have no such scope, since it will be limited to a single increment per event.

N.B. The quoted text in my reply was copied before your post was edited.

[737 Driver]

An important point not often discussed, was whether any of those other systems were operating at the same time as MCAS and stick shaker.

In the Lion Air preliminary accident reports, illumination of the FEEL DIFF PRESS warning was cited in the maintenance history, and the post-Lion Air emergency AD includes it as a symptom of the failed AOA. This would be an indication of the Elevator Feel Shift Module activation. The STS would not have been active with flaps up. We know about the stick shaker and MCAS. There are no published DFDR traces for Leading Edge Device position, so we don't know for sure if the Autoslats system was active, but hopefully that information will be included in future updates. The Ethiopian preliminary and at least one incident report I found in the Aviation Safety Reporting System database describes the presence of small yaw oscillations which would be expected if the yaw damper response was suppressed.

[PerPurumTonantes]

No, the six minutes was the result. Had the PF used electric trim ANU they could have had as much time as they wanted to try a memory item, like turning off the trim system.
Some aircraft do not have a manual trim wheel, this one does. Get the trim somewhere near correct with the electric trim switch and then turn off the trim. As 737 Driver keeps saying, this is not test pilot territory. It is basic flying skills, trim away the pressure.
Valid in a normal out of trim situation. But when an automatic system is actively pushing trim nose down to that extent? Repeatedly? And the only way to fix the problem (MCAS) is to switch out the solution (elec trim) as well? Yes this is test pilot territory.

[737 Driver]

Valid in a normal out of trim situation. But when an automatic system is actively pushing trim nose down to that extent? Repeatedly? And the only way to fix the problem (MCAS) is to switch out the solution (elec trim) as well? Yes this is test pilot territory.

As far as defeating the MCAS input, the ONLY thing required of the Captain was to trim the aircraft normally. The yoke trim switch will trump MCAS every single time. He did not need the strength of his arms, he only need the strength of this left thumb.

Yes, MCAS will try again after a 5-second delay, but that motion would have been stopped as easily as the first - if the Captain had simply applied normal trim technique. He could have done this all day long, and MCAS never would have driven the stab to an unrecoverable position. At some point, after tiring of this back and forth, one of the pilots could then have disabled MCAS by using the trim cutout switches.

No, this is most definitely not test pilot territory. This isn't even commercial pilot territory. Trimming the elevator/stab to relieve control pressures is private pilot territory. Heck, we even expect this level of skill from a student pilot before they are cleared solo!

Set the pitch, set the power, check the performance, and trim. That is all that was required to get this aircraft safely away from the ground.

[michaelbinary]

So, its that piss easy is it ?.

So 4 professional pilots failed to press a little trim switch to keep the aircraft in trim and killed a few hundred people.

Really ?, there is something wrong with a system that causes 2 planes to crash like that, if the solution was soooooooooo simple.

Shame you wern't on the plane to instruct them all.

[737 Driver]

So, its that piss easy is it ?.

So 4 professional pilots failed to press a little trim switch to keep the aircraft in trim and killed a few hundred people.

Yes, it really was that easy. As you say, they were all professional pilots. And what exactly should be our expectations of a professional pilot? I would think that being able to fly their aircraft (and not rely on the automation to do it for them) in the presence of a distraction would be a pretty minimum requirement.

The first and most important step of any aircraft emergency is FLY THE AIRCRAFT. Set the pitch, set the power, check the performance, trim the aircraft. Pretty basic stuff.

Sadly, this has not been the first time, and probably won't be the last time, that one of the primary causes of a fatal accident was because at least one of the pilots was not FLYING THE AIRCRAFT.

As to the question of WHY four professional pilots failed to revert to these basics of airmanship, that should be a major topic of the accident investigation.

[michaelbinary]

Easy to criticize from the comfort and safety of your arm chair with the help hindsight, no urgency to say or do anything.
Seen lots of people like you.

Nothing takes away the fact that 2 aircraft crashed and killed everybody when there was essentially nothing wrong with them, and 4 pilots all made the same simple mistake of not using the electric trim tab to normalise the trim.

That stinks. Any common sense would tell you, that stinks.

If that is really the case which I dont think it is, Boeing have screwed up big time and deserve to be sued into the ground.

[737 Driver]

Easy to criticize from the comfort and safety of your arm chair with the help hindsight, no urgency to say or do anything.


So you're perfectly okay with letting major lapses in airmanship slide even though hundreds a people might die sometime in the future because the deficiency wasn't ever addressed?

Boeing needs to fix their problem, but the professional pilot corp can just continue to whistle past the graveyard when their is an obvious issue with crew training and proficiency?

[GarageYears]

So, its that piss easy is it ?.

So 4 professional pilots failed to press a little trim switch to keep the aircraft in trim and killed a few hundred people.

Really ?, there is something wrong with a system that causes 2 planes to crash like that, if the solution was soooooooooo simple.

Actually it was that easy.

Equally, leaving the flaps at flaps 1, would have suppressed all MCAS operation, and again they would have all the time their fuel load allowed to "figure it out".

You probably won't like this, but it's clear there is a generation of pilots currently responsible for hundreds of lives per flight, that know real well how to select the autopilot. Much else seems a bit of a challenge. Worry, much.

- GY

[michaelbinary]

Well neither of you were there, and neither of you know exactly what did or didnt happen or what the pilots did or didnt do to fix the issues.

I dont beleive the situation was as simple as you would like to make out.

You have the benefit of sitting there smugly, saying, I would do this or that, or they should have done this or that.
They were presented with a situation that they were not trained to respond to, or even told it was there or what it did, such was Boeing's arrogance.
There was probably confusion, lack of information as to what exactly was happening, and therefore confusion of what to do to correct it, and at the same time not making the issue whatever it was, worse.

If you are unlucky you may get the chance one day to prove to the world just how wonderful you both are.

[GordonR_Cape]

As far as defeating the MCAS input, the ONLY thing required of the Captain was to trim the aircraft normally. The yoke trim switch will trump MCAS every single time. He did not need the strength of his arms, he only need the strength of this left thumb.

We do not know that for sure, since nobody has provided any definitive proof, and the pilots that tried clearly failed. It is clearly in Boeing's interest to imply that there was pilot error, but an objective crash investigation may find differently. It may turn out that some weird software glitch, or wiring error, or activation of speed trim (in addition to MCAS), may have prevented the pilots from raising the nose.

[737 Driver]

We do not know that for sure, since nobody has provided any definitive proof, and the pilots that tried clearly failed. It is clearly in Boeing's interest to imply that there was pilot error, but an objective crash investigation may find differently. It may turn out that some weird software glitch, or wiring error, or activation of speed trim (in addition to MCAS), may have prevented the pilots from raising the nose.

I'm not sure what level of definitive proof you are looking for, however, if you look at the DFDR output in the ET302 preliminary report, you will see that the Captain was making stab trim inputs and the stab was indeed moving. If you look closely at about the 5:40:25 mark, you will even see a pilot nose up trim input that stopped and reversed the ongoing MCAS input. This is strong evidence that the system was working as designed. As previously mentioned, Speed Trim was not active after the flaps were retracted, nor were there any indications on the DFDR trace of any automatic trim inputs other than MCAS. The Elevator Feel Shift module may have been active thus increasing elevator control pressures, but that would have only accentuated the need to trim off the control pressures.

As I keep saying, there were multiple causes to these accidents. Design issues, oversight issues, maintenance issues, and training issues. However, there were also crew performance issues. They all need to be addressed.

.

[Organfreak]

Actually it was that easy.

Equally, leaving the flaps at flaps 1, would have suppressed all MCAS operation, and again they would have all the time their fuel load allowed to "figure it out".

You probably won't like this, but it's clear there is a generation of pilots currently responsible for hundreds of lives per flight, that know real well how to select the autopilot. Much else seems a bit of a challenge. Worry, much.
- GY

Clearly, Boeing and their Good Ol' Boys are culpable here, but, [FWIW=0] I have completely lost faith in the supposed competence of the unseen pilots behind that door, and I'm not going to fly anymore unless it's an absolute necessity! Too much of a gamble. Apologies to the 100s of thousands of you who ARE competent and responsible.

[737 Driver]

Well neither of you were there, and neither of you know exactly what did or didnt happen or what the pilots did or didnt do to fix the issues.

I dont beleive the situation was as simple as you would like to make out.



There are lots of comments on this and other threads about how Boeing screwed up, how the FAA screwed up, how the airlines screwed up, and how maintenance screwed up without much in the way of dissenting voices. We expect them to fix their mistakes, don't we? Well how about the professional pilot corps? Are we willing to acknowledge that there were deficiencies on the part of the crew?

Listen, I get it. A lot of us here are pilots, and we hate to contemplate that someone within our group, for whatever reasons, fell short of the expectations of a professional pilot. It is easy to point fingers across the fence, much harder to look in the mirror. However, the first step in solving a problem is acknowledging a problem exist. Issues with automation dependency, pilot proficiency and deterioration of basic flying skills has been a constant presence in our industry for quite some time. I don't care what airline you fly for or how many hours you have, you have likely encountered someone (perhaps even yourself) who was no longer comfortable with turning off the automation and hand-flying in other than day VMC when there were no other distractions. This is a problem, and it needs to be addressed.

We do not control our training departments, but we do control how we approach our flying duties. If you are a professional pilot and you are honestly telling yourself that you could not have done any better given the MAX failed AOA scenario, then you owe it to yourself and your passengers to do something about it. Yes, we all now know the details about MCAS and how to deal with it. That's not what I'm talking about. The next malfunction you have may be equally unique and initially confusing.

If you are not comfortable with your hand-flying skills, then do something about it. Turn off the magic when you can. Hand fly the aircraft all the way to level off and all the way down. Captains, encourage your FO's to do the same. Automation is not always your friend, and sometimes it is your enemy. Start making note of pitch and power setting at different phases of flight. Pull out the manuals more often. Know your aircraft's memory items and limitations. Read incident reports and consider what you would do differently. Make training events in the sim count. If your sim instructor has the discretion, ask to see something different or something you haven't seen in awhile. Set a high standard for yourself and your crew. Yes, you can get by with much less effort for the same amount of pay 99.9% of the time. However, that last 0.1% can quite literally be the difference between life and death.

All this advice isn't anything you haven't already heard before. Just do it.

[Lost in Saigon]

Actually it was that easy.

Equally, leaving the flaps at flaps 1, would have suppressed all MCAS operation, and again they would have all the time their fuel load allowed to "figure it out".

You probably won't like this, but it's clear there is a generation of pilots currently responsible for hundreds of lives per flight, that know real well how to select the autopilot. Much else seems a bit of a challenge. Worry, much.

- GY

Yes, I agree. It SHOULD have been easy, but for some unknown reason, it was not.

There are at least three things that could have saved them:

1) leaving the flaps extended to stop MCAS operation
2) using electric trim to stop MCAS operation
3) using the stab trim cutout switches to stop MCAS operation

They did NONE of these things CORRECTLY. We need to find out why.

Hopefully the final report will give us the answer.

[GordonR_Cape]

I'm not sure what level of definitive proof you are looking for, however, if you look at the DFDR output in the ET302 preliminary report, you will see that the Captain was making stab trim inputs and the stab was indeed moving. If you look closely at about the 5:40:25 mark, you will even see a pilot nose up trim input that stopped and reversed the ongoing MCAS input. This is strong evidence that the system was working as designed. As previously mentioned, Speed Trim was not active after the flaps were retracted, nor were there any indications on the DFDR trace of any automatic trim inputs other than MCAS. The Elevator Feel Shift module may have been active thus increasing elevator control pressures, but that would have only accentuated the need to trim off the control pressures.

As I keep saying, there were multiple causes to these accidents. Design issues, oversight issues, maintenance issues, and training issues. However, there were also crew performance issues. They all need to be addressed.

.

I certainly did look at the ET 302 FDR readout, before posting my comment. The question is why did the pilot stop nose up trim inputs at 2.5 degrees? There were still considerable control column forces shown on the FDR. Why would any pilot only half trim out those forces, unless they were stopped by software or hardware? My question remains unanswered...


https://cimg0.ibsrv.net/gimg/pprune.org-vbulletin/1453x879/et302_fdr_trace_specifics_c8e7c4682349647e1c9334fc1dc18e72ef 87f9c0_et302_fdr__35c8d33e010e87acb5356d4ce398a06fb7460229.g if

[PerPurumTonantes]

Yes, it really was that easy.
Do you know what their long term shift pattern was? Have you read the FlyDubai Rostov crash thread? Do you know why they didn't quite get it back in trim? Why they just blipped the switches during the second MCAS activation? They did pretty much everything you ask for, just not quite enough of it. Why? They even identified the issue and operated the cutouts.

Perhaps misleading alarms, violence of stick shaker masking clack of trim, possibility of a number of causes to go through, speed of MCAS operation, repetition of MCAS, startle factor, no sim training for specific event? Fatigue? Heck even Sully said he had a lot of luck, and it took him quite a few seconds for real cognition to come in. And he had none of the above to contend with, just a nice quiet cockpit.

They were acting as test pilots for a failure mode that was easily predictable, that never should have been allowed to pass design stage never mind FMEA and testing. Boeing's responsibility.

You've made up your mind but I'd prefer to give a little slack to two dead guys who had to add "systems faulting engineer" to their CV at the drop of a hat.

[MurphyWasRight]

Slight reframing of the issue starting with some assumed true statements, mostly applies to both accidents although the lion air prelim report does not show control column positions.

1: The pilots were initially aware that the plane was out of trim through no action on their part.

2: They counteracted some but not all of the MCAS inputs.

3: The last moments of both flights saw brief manual trim inputs, woefully insufficient.

The question is why did both crews only partially retrim and then loose it at the end?
Possible answers, not mutually exclusive of course.

A: They were confused by all the warnings and just lost the plot.

B: They had no training with grossly out of trim conditions and were used to short inputs.

C: Something confused them after the initial re-trim to believe the airplane was close being in trim, despite the obvious control column in lap.
Could they have believed that some other factor was causing this?

D: Some biomechanical or other issue prevented them from actuating the switches.

As others have stated 'basic airmanship' should have worked but clearly something was missing.
Note, There were also a large number of other factor that could have prevented these accidents, especially ET, this is just about why the crew did what they did.

[737 Driver]

I certainly did look at the ET 302 FDR readout, before posting my comment. The question is why did the pilot stop nose up trim inputs at 2.5 degrees? There were still considerable control column forces shown on the FDR. Why would any pilot only half trim out those forces, unless they were stopped by software or hardware? My question remains unanswered...


I had the exact same question when I first read the accident report. I spent a lot of time looking for evidence that the trim motor stalled or the trim switch wasn't working. However, none of the accident evidence or any historical data supports either of these conclusions.

One of the most telling pieces of evidence in this report, however, is that the Captain repeatedly tried to engage the automation (three times) in a situation that specifically precluded it. This is evidence of someone with a strong case of automation dependency. People with significant automation dependency also demonstrate a deterioration in basic hand-flying skills. Combine that with the startle effect and the distraction of the active stick shaker, it is entirely conceivable that the Captain suffered from cognitive overload and simply forgot to trim because it had never become a thoroughly engrained behavior.

[Jetstream67]

I can understand a reluctance to fight the aircraft to dramatically alter the trim when the issue is not clear.

Many road vehicle crashes are made worse by tentative breaking when only full force could have helped. (Several car makers initially added brake force acceleration systems to increase partial braking towards full pressure for this reason - now augmented by radar anti-collision systems)

[nyt]

The STS would not have been active with flaps up.
So, do you still consider MCAS an STS subsystem ?

[ernst_mulder]

Those two short electric trim-up commands at the end of both crashes just before enter info a dive keep puzzling me... Farfetched maybe, and probably repeating what others have suggested already, but what about:

E: The electric trim didn't move the trim wheel at all. Flip up once, no trim wheel movement. Try it another time, still no movement. The pilots conclude electric trim it isn't working and proceed (and the MCAS steps in again).

SLF

[sky9]

Can I just highlight that the F/O had 200hrs experience. I didn't get a commercial pilots licence until I had flown 230 hours and didn't fly jets until I had 1800hrs. The company that I flew 737's for in the UK in the early 1970's required 2000 hours before offering a job in the right hand seat.

This incident was to all intents and purposes a single pilot operation.

[edmundronald]

Yes, I agree. It SHOULD have been easy, but for some unknown reason, it was not.

There are at least three things that could have saved them:

1) leaving the flaps extended to stop MCAS operation
2) using electric trim to stop MCAS operation
3) using the stab trim cutout switches to stop MCAS operation

They did NONE of these things CORRECTLY. We need to find out why.

Hopefully the final report will give us the answer.

So above-average pilots would have saved the plane and below average pilots lose it. Let's see, there are 50% of below average pilots in the world, you better be careful when an SLF to get in the right plane - although of course only above average pilots participate in PPrune.

Gimme a break - the issue is why were the pilots subjected to this horrible situation, where being average but not good meant bye bye for the SLF?

Edmund

[Loose rivets]

Posted in error on the parallel thread.

737Driver post number #4304Quote:First of all, some of you might be surprised to learn that in a stall condition, the STS will trim the stab nose down at the exact same speed as MCAS and can do so continuously until it hits the stop. This is far more authority than MCAS ever had. Why is not a problem? Because the STS will respect the control column trim cutout switches. These are not the pedestal switches that are activated by the pilot. These limit switches are located at the base of the control column and prevent trimming opposite the direction of column displacement. That is, if a pilot is pulling back on the yoke, then nose down trim is inhibited. If someone is pushing forward on the yoke, nose up trim is inhibited. Thus the authority of STS is limited by the control inputs of the pilot.
One of the bees in my bonnet has been the removal of that column switch on the MAX. Not just the bypassing of its logic under certain conditions - but the total physical removal.

Despite being in my 80th year, (and posting on the wrong thread) statements like that still stick firm, like the unwinding of MCAS. The switch removal (from under the floor at base of column) never really got a clear answer. Well it did: a dedicated post saying 'I don't know'.

I try to filter my information input, and of course a lot is from the Times publication and our engineering friend in Seattle. The switch is either there, or not there, but it seems if it is, its functionality can be obviated as per 737 Driver's earlier post.

Back to his assertion that it was flyable. I get a sickening feeling that something else apart from psychological overload might be wrong. There are so many able minds chasing the suspected faulty input to that 47' of flying surface, along with the associated loading difficulties, that you'd think remedial action was just a matter of time. But the thing I fear most is months of rewriting of code, some agreement on what is now certification and the craft back in the sky carrying a ghost in the machine.

There is too much pressure to get airborne.

'We' seem to have everything we need to throw light on those terrible moments, but the very fact that so many skilled people, not least of all on this forum, can disagree on the extent of the pilot culpability worries me deeply. There is a huge dichotomy in the judgement of these flying professionals.

[737 Driver]

So, do you still consider MCAS an STS subsystem ?

That was actually Boeing's position, not mine. That being said, there are regime's in which the traditional STS is inhibited, and regimes in which the MCAS is inhibited. These regime's are mutually exclusive.

[737 Driver]

So above-average pilots would have saved the plane and below average pilots lose it.

Someone may have said this, but that is certainly not my position.

Let me restate it. There are certain expectations of a professional pilot who is entrusted with the lives of their passengers and crew. One of those expectations is that, in the presence of an unexpected aircraft state, they should be able to demonstrate the basic airmanship skills of hand-flying their aircraft by establishing the appropriate attitude and power settings, monitoring aircraft performance (speed, altitude, rate of climb, etc), and keeping the aircraft in proper trim.

This is an expectation for ALL professional pilots. Not above average. Not average. ALL.

[michaelbinary]

I certainly agree with your comments about the hand flying skills.
On an 8 hour atlantic sector how much time does a pilot actually fly the aircraft ?, 5 mins, bit more bit less ?.
How out of practice do you get after 5 or 10 years of just systems management ?.
I know some commercial pilots fly light aircraft for fun, but how many dont ?.
I think all commercial pilots should have to fly a manual light aircraft and fly some aerobatics at least 5 hours a year.

[737mgm]

737 driver is obviously a professional pilot flying the 737. As a 737 NG Captain myself I can assure you he knows what he is talking about. He is an expert on the subject and the majority of the posters arguing with him are not. It is amazing and at the same time quite frustrating to observe the conviction with which people are stating their opinions on here even though they are actually clueless.
Instead of posting your ignorant armchair pilot comments, why don't you take some time to read up on the procedures to fly the 737. Read the official Boeing documents. Talk to 737 pilots and ask them how they are trained. Of course this will take a lot longer and require much greater effort than posting your oblivious comments but then you might be a little bit closer to actually being able to judge how these pilots performed.

[slacktide]

- MCAS was designed to activate at a much lower AOA, independent of the stick shaker.
- MCAS was designed to activate under many areas of the flight envelope, independent of the stick forces and airspeed.

2 things -

1) Do you have a reference for what AOA MCAS activates at when compared to the stickshaker AOA, preferably from a primary source, i.e. the manufacturer, a regulatory body, or similar? I've looked for that but have been unable to find it... it's getting difficult to find original data among all the poorly written media interpretations.

2) I do not believe that is true. Airspeed is used both as in input to determine the MCAS activation AOA, and it is used to determine the magnitude of the stab trim input. The first time that we learned anything about MCAS was in the November 8/9/10 timeframe in a letter from Mike Michaelis, APA safety committee chairman. It was an unpublished letter to APA members but was extensively reported in the media, and claimed to include a description of MCAS that was provided by Boeing. Here's a contemporary PPRUNE link - https://www.pprune.org/10307740-post978.html

The MCAS function becomes active when the airplane Angle of Attack exceeds a threshold based on airspeed and altitude. Stabilizer incremental commands are limited to 2.5 degrees and are provided at a rate of 0.27 degrees per second. The magnitude of the stabilizer input is lower at high Mach number and greater at low Mach numbers. The function is reset once angle of attack falls below the Angle of Attack threshold or if manual stabilizer commands are provided by the flight crew. If the original elevated AOA condition persists, the MCAS function commands another incremental stabilizer nose down command according to current aircraft Mach number at actuation.

[michaelbinary]

Hmmmm, is he the same as the 4 professional pilots who were flying the two planes that crashed ?.
Maybe all of those 4 were below average, and he is above average ?.

Being professional in any job doesnt make you automatically good at it at all. it just means you get paid for it.

[slacktide]

That was actually Boeing's position, not mine.

That's also the FAA's position, at least based on the most recent FSB report draft. https://www.faa.gov/aircraft/draft_docs/media/afx/FSBR_B737_Rev17_draft.pdf

B-737-MAX Maneuvering Characteristics Augmentation System (MCAS). The Speed Trim System (STS) provides speed and pitch augmentation. Speed stability augmentation is provided by the Speed Trim function of STS. Pitch stability augmentation is provided by the MCAS function of STS. MCAS ground training must (https://www.faa.gov/aircraft/draft_docs/media/afx/FSBR_B737_Rev17_draft.pdf)address system description, functionality, associated failure conditions, and flight crew alerting. These items must be included in initial, upgrade, transition, differences, and recurrent training.

[Ian W]

So above-average pilots would have saved the plane and below average pilots lose it. Let's see, there are 50% of below average pilots in the world, you better be careful when an SLF to get in the right plane - although of course only above average pilots participate in PPrune.

Gimme a break - the issue is why were the pilots subjected to this horrible situation, where being average but not good meant bye bye for the SLF?

Edmund

Average professional pilots even below average professional pilots should note and correct out of trim flight. This is C-172 stuff and is not complicated. The first Lion Air flight showed that the Max with MCAS erroneously operating is flyable by repeated trimming, the second flight showed that had the captain continued trimming back to in trim the flight may not have crashed; it was only when the trimming was reduced to the occasional blip that control was lost. If trimming had continued and a return to airport was chosen as soon as the flaps were lowered MCAS would have stopped and the aircraft could have recovered.

Boeing had an expectation that qualified 737 pilots would continually keep the aircraft in trim and that would stop MCAS, They also had the expectation that repeated uncommanded nose down stab trim by the aircraft systems would result in the stab trim being switched off by a qualified 737 pilot. Boeing was wrong. 737 pilots qualified and allocated their seats by their airline did not do as Boeing expected. It seems that automation surprise plus all the alerts aural and haptic (the stick shaker) amplify the automation surprise to a level where some pilots can no longer 'fly the plane'. It may be that the simulation training may not provide the visceral reality of an emergency in the real aircraft resulting in cognitive tunneling or even an attempt to carry on as if the system failure hadn't happened. I and no doubt others here, have witnessed examples where competency shown in the simulator falls apart in the 'real world',

So while Boeing is building aircraft that would be easily flyable by 737 pilots from the 1970's who usually flew manually and often preferred to switch off the automation; the training systems and the airline training constraints are producing pilots who avoid and are instructed to avoid, manual flying and who are better at system management. This has become apparent in this thread where there is a rough distinction between the 'switch it off' - pitch and power - fly the aircraft group (smaller); and, the systems managers who need to know all the aspects of the system with an FMEA and NNCs geared to each of those failure modes. The first group are aghast the aircraft were not recovered, the second are aghast that a new part of the system was not flagged up by Boeing and was not briefed with precise NNCs.

Aviation seems to have met the cross over point where avionics manufacturers and airframers can no longer assume that any bag of bolts on failure will be picked up by someone 'aviating', 'navigating' and 'communicating' - setting pitch, power, trimming and flying the aircraft; they now have to remove all potential single-points-of-failure, fail soft, gracefully degrade, and, if possible automation should carry on and cope with all potential failure modes. However, that is a slippery slope as it is a self fulfilling prophecy the more capable the automation the less capable the pilots. The only ones happy about that are the beancounters who will further reduce simulation time accelerating the problem.

[GordonR_Cape]

737 driver is obviously a professional pilot flying the 737. As a 737 NG Captain myself I can assure you he knows what he is talking about. He is an expert on the subject and the majority of the posters arguing with him are not. It is amazing and at the same time quite frustrating to observe the conviction with which people are stating their opinions on here even though they are actually clueless.
Instead of posting your ignorant armchair pilot comments, why don't you take some time to read up on the procedures to fly the 737. Read the official Boeing documents. Talk to 737 pilots and ask them how they are trained. Of course this will take a lot longer and require much greater effort than posting your oblivious comments but then you might be a little bit closer to actually being able to judge how these pilots performed.

I'm not a pilot, but also not clueless (having both an engineering and programming background), and having read all 4000 plus posts in this thread. My questions have not been about how to fly a B737, but how the MAX and MCAS actually work, with stuck high AOA data. No pilot on this forum has actually experienced this, either in person or in the simulator. I (and others) do not accept as verbatim truth, the system descriptions provided by such pilots, however experienced. The same applies even more to Boeing, who were evasive about the existence of MCAS, provided limited documentation, and have much to gain by shifting blame, and good (legal) reasons for not disclosing more details.

Only an independent engineering verification (not paper documents and diagrams) of the details of systems involved in the crashes, and of the proposed revisions to MCAS, will provide all the answers. My viewpoint has nothing to do with blame, just looking for the truth, which may take some time (years?). In the meantime any assertion that the pilots should have done X, can be countered by an assertion that perhaps the software or hardware did not allow that to happen. The same is true of any crash investigation, where both complex systems and human factors were involved.

[737mgm]

I'm not a pilot, but also not clueless (having both an engineering and programming background), and having read all 4000 plus posts in this thread. My questions have not been about how to fly a B737, but how the MAX and MCAS actually work, with stuck high AOA data. No pilot on this forum has actually experienced this, either in person or in the simulator. I (and others) do not accept as verbatim truth, the system descriptions provided by such pilots, however experienced. The same applies even more to Boeing, who were evasive about the existence of MCAS, provided limited documentation, and have much to gain by shifting blame, and good (legal) reasons for not disclosing more details.

Only an independent engineering verification (not paper documents and diagrams) of the details of systems involved in the crashes, and of the proposed revisions to MCAS, will provide all the answers. My viewpoint has nothing to do with blame, just looking for the truth, which may take some time (years?). In the meantime any assertion that the pilots should have done X, can be countered by an assertion that perhaps the software or hardware did not allow that to happen. The same is true of any crash investigation, where both complex systems and human factors were involved.

There are two issues at hand here: One issue is everything surrounding MCAS which you are interested in. Another issue is, if these accidents were preventable by carrying out the required Boeing procedures or by applying basic flying skills respectively, despite MCAS activating.

[Chronus]

Posted in error on the parallel thread.

737Driver post number #4304Quote:
One of the bees in my bonnet has been the removal of that column switch on the MAX. Not just the bypassing of its logic under certain conditions - but the total physical removal.

Despite being in my 80th year, (and posting on the wrong thread) statements like that still stick firm, like the unwinding of MCAS. The switch removal (from under the floor at base of column) never really got a clear answer. Well it did: a dedicated post saying 'I don't know'.

I try to filter my information input, and of course a lot is from the Times publication and our engineering friend in Seattle. The switch is either there, or not there, but it seems if it is, its functionality can be obviated as per 737 Driver's earlier post.

Back to his assertion that it was flyable. I get a sickening feeling that something else apart from psychological overload might be wrong. There are so many able minds chasing the suspected faulty input to that 47' of flying surface, along with the associated loading difficulties, that you'd think remedial action was just a matter of time. But the thing I fear most is months of rewriting of code, some agreement on what is now certification and the craft back in the sky carrying a ghost in the machine.

There is too much pressure to get airborne.

'We' seem to have everything we need to throw light on those terrible moments, but the very fact that so many skilled people, not least of all on this forum, can disagree on the extent of the pilot culpability worries me deeply. There is a huge dichotomy in the judgement of these flying professionals.

It is the last paragraph of the above post that also concerns me. I am dismayed to read on this forum that there are those who suspect culpability on the part of the pilots. Here is an extract from Dominic Gates article in the Seattle Times "Flawed analysis, failed oversight: How Boeing, FAA certified the suspect 737 MAX flight control system"As Boeing hustled in 2015 to catch up to Airbus and certify its new 737 MAX, Federal Aviation Administration (FAA) managers pushed the agency’s safety engineers to delegate safety assessments to Boeing itself, and to speedily approve the resulting analysis."

The full article may be accessed at : https://www.seattletimes.com/business/boeing-aerospace/failed-certification-faa-missed-safety-issues-in-the-737-max-system-implicated-in-the-lion-air-crash/

"But the original safety analysis that Boeing delivered to the FAA for a new flight control system on the MAX — a report used to certify the plane as safe to fly — had several crucial flaws."How could it be that when so much has been published about this accident, some can still consider culpability may still be suspected on the part of the pilots. Is this not yet another case of a race between competitors, just as it was back in the late 60`s, early 70`s for the first wide body jets and the Turkish DC10 crash.
Always easy to blame the pilots, perhaps this is why in today`s age of high tech, computers, robotics, automation, that pilots are still "carried" on board the modern airliner.

[WillFlyForCheese]

So above-average pilots would have saved the plane and below average pilots lose it. Let's see, there are 50% of below average pilots in the world, you better be careful when an SLF to get in the right plane - although of course only above average pilots participate in PPrune.

Gimme a break - the issue is why were the pilots subjected to this horrible situation, where being average but not good meant bye bye for the SLF?

Edmund

Perhaps "below average" pilots shouldn't be hauling live cargo? Or - perhaps a "below average" pilot can still competently fly a malfunctioning aircraft. I'm not willing to accept that the spectrum of commercial airline pilots include, as "below average," pilots who cannot do what many recognize here would have saved the day (and what the penultimate Lion Air crew was able to do). But - if that's where the industry is headed - perhaps the aircraft do need to be smarter and in more control . . . .

[michaelbinary]

As I said previously, it's about MONEY, and shortcuts, and covering up as much **** as they can to try to minimize the massive law suits that are now in progress.

Self certification...............WTF..........how is that ever safe.

[Water pilot]

The "children of the magenta line" is a real issue in my opinion, but I do not think that it has anything to do with either crash. There is no evidence that the pilots were deficient in hand flying -- that may be a surprising statement to some who have been following this discussion, but "hand flying" doesn't mean "physically crank on levers and wheels to control the aircraft's control surface." That is what the pilots were being asked to do because there was no way to turn off HAL -- all they could do was bypass him by crippling the same controls that they were using and revert to the emergency backup. However, it was not even that simple, now we are being told that the mistake of the Lion Air pilots is that they turned off the power trim system too early and instead should have used the power switches to revert the trim and then turned it off while at the same time blipping it to reset MCAS-- which is what it appears that they were tying to do just before the plane pitched nose down into terrain as HAL came roaring back.

The emergency manual backup wheels that they were expected to use is so disregarded that most modern planes do not have it and was allegedly made smaller in the NEO in order to make space for the display screens. I see an analogy to a modern ship's wheel which is hardly ever touched because everybody uses the hydraulic systems that are part of the ship's autopilot. That doesn't mean that captains are always steering the boat by entering courses into the autopilot or worse, are children of the magenta line, it just means that there is no point to trying to turn a large ship by cranking like the devil on a relic from the days of square rigged sailboats and 100-person crews. If a captain were slow to realize that his NFU (non-follow up control, the way that you use power steering) control was sometimes slipping in a few extra degrees of turn than what he commanded we would not put him in the same class as a pleasure boater whose only experience with navigation is to touch points on the Garmin screen and then hit "engage autopilot." He or she may have been deficient in diagnosing the problem, or deficient in noticing that the ship was headed somewhere other than commanded, but that is an entirely different issue and one that probably relates more to experience.

[MurphyWasRight]

Perhaps "below average" pilots shouldn't be hauling live cargo? Or - perhaps a "below average" pilot can still competently fly a malfunctioning aircraft. I'm not willing to accept that the spectrum of commercial airline pilots include, as "below average," pilots who cannot do what many recognize here would have saved the day (and what the penultimate Lion Air crew was able to do). But - if that's where the industry is headed - perhaps the aircraft do need to be smarter and in more control . . . .

Everyone makes mistakes at some point or another, especially under stress. I personally try to keep myself at least 2 or preferably more mistakes (mine or others) away from a bad outcome, driving, woodworking or whatever.

The ET crew made one or more mistakes, not all of them significant, Sully succeeded despite neglecting to set transponder code.

One probably significant one was loss of awareness/control of speed, which contributed to inability to manually trim.

It is possible they decided stick shaker was spurious and since the speeds were not all that divergent (until later) they may have discounted uas warnings, hence attempt (and success for a while) to use autopilot which probably reinforced 'spurious' impression.
Had they been perfect they would have kept flaps down etc, although if they "perfectly" reacted to stall warning it might not have gone as well.

They did follow the runaway trim procedure but were apparently unable to manually trim then lost it when re-enabling electric trim.
Lack of manual trim and inability to disable only automatic trim (as on NG) was someone else's mistake, not theirs.

So how many mistakes are allowed? One hopes the number is greater than 1.

[MurphyWasRight]

Heard tell that ex President Bush was very upset when told that about half of american students were below average in math.

There is a spectrum of skills and abilities in every field. The hard part can be drawing a distinction between 'below average' and incompetent.

One other datapoint is that something like 70 percent of drivers consider themselves above average.
While I don't know the stats for pilots, any professional pilots reading this thread consider themselves below average?

Of course mathematicians get upset with generic use of the term average (mean of them) but that is a different thread somewhere in a forum far far away.

Assuming normal distribution 75% of all flights have at least one below average pilot in the cockpit.

[Brosa]

I had the exact same question when I first read the accident report. I spent a lot of time looking for evidence that the trim motor stalled or the trim switch wasn't working. However, none of the accident evidence or any historical data supports either of these conclusions.

One of the most telling pieces of evidence in this report, however, is that the Captain repeatedly tried to engage the automation (three times) in a situation that specifically precluded it. This is evidence of someone with a strong case of automation dependency. People with significant automation dependency also demonstrate a deterioration in basic hand-flying skills. Combine that with the startle effect and the distraction of the active stick shaker, it is entirely conceivable that the Captain suffered from cognitive overload and simply forgot to trim because it had never become a thoroughly engrained behavior.Four times.
Take a look at 05:43:15, just after they made those two insufficient trim inputs. They got a warning there from a failed attempt to engage the autopilot.

Unfortunately the report has left out plenty of what was said and done in that last phase when they lost control.

[WillFlyForCheese]

Heard tell that ex President Bush was very upset when told that about half of american students were below average in math.

There is a spectrum of skills and abilities in every field. The hard part can be drawing a distinction between 'below average' and incompetent.

One other datapoint is that something like 70 percent of drivers consider themselves above average.
While I don't know the stats for pilots, any professional pilots reading this thread consider themselves below average?

Of course mathematicians get upset with generic use of the term average (mean of them) but that is a different thread somewhere in a forum far far away.

Assuming normal distribution 75% of all flights have at least one below average pilot in the cockpit.

"Average" is relative - correct? Take US military service . . . there is an "average" soldier, and then, perhaps, an "average" Navy SEAL, or US Army Delta Force. Or, if you will, military of any country and, then, Canada's Joint Task Force 2; Denmark's Jaeger Corps; or Britain's Special Air Service . . .

The average of an elite group will always be above the average of a larger group. Indeed, the larger group may include those that shouldn't be in the armed forces at all. The more elite groups will all be more than competent - and each elite group will statistically have an average, below average, and above average.

My point was, and is, that commercial airline pilots should be an above-average group to begin with. Leaving the "below average" pilot not far off from the above average pilot - any one of which is highly capable individually. For many reasons - that is not how the profession has evolved. Low wages? Poor treatment? Perhaps the airlines themselves are to blame as well for degrading the profession?

I digress.

[Brosa]

The "children of the magenta line" is a real issue in my opinion, but I do not think that it has anything to do with either crash. There is no evidence that the pilots were deficient in hand flying -- that may be a surprising statement to some who have been following this discussion, but "hand flying" doesn't mean "physically crank on levers and wheels to control the aircraft's control surface." That is what the pilots were being asked to do because there was no way to turn off HAL -- all they could do was bypass him by crippling the same controls that they were using and revert to the emergency backup. However, it was not even that simple, now we are being told that the mistake of the Lion Air pilots is that they turned off the power trim system too early and instead should have used the power switches to revert the trim and then turned it off while at the same time blipping it to reset MCAS-- which is what it appears that they were tying to do just before the plane pitched nose down into terrain as HAL came roaring back.To me it appears that the last crash was a case of "magenta line".

1. Stall warning and stick shaker on rotation
Solution: tried to engage the autopilot at 400 ft

2. Apparantly false stick shaker due to erroneous inputs + unreliable airspeed
Solution: tried to engage the autopilot at 600 ft

3. Still stick shaker due to erroneous inputs from left side
Solution: finally succeeded to engage the left autopilot at 1000 ft

4. Aircraft is grossely out of trim and in an overspeed condition, making it hard to fly
Solution: tried to engage the autopilot

https://cimg0.ibsrv.net/gimg/pprune.org-vbulletin/1779x1140/magenta_8d9905c8cf0fbf8a0b21bcaa7c814c868486182d.jpg

[DaveReidUK]

Heard tell that ex President Bush was very upset when told that about half of american students were below average in math.

If you use "average" in the most commonly used sense meaning the arithmetic mean of a distribution then there is no reason why half of the population should necessarily be "below average".

[MurphyWasRight]

If you use "average" in the most commonly used sense meaning the arithmetic mean of a distribution then there is no reason why half of the population should necessarily be "below average".
As i said:
Of course mathematicians get upset with generic use of the term average (mean of them) but that is a different thread somewhere in a forum far far away.

I agree that by that meaning you are correct, a better statement is that if you arrange 101 people by height (or whatever) in a row 50 will be to left of the middle person and 50 to the right.
Would make the joke a bit off though.

The real question on pilots is how to train and test the 'acceptable' not perfect pilot. I sense that a lot of training has devolved into following scripts in a sim. One could make the point that any situation that can be covered by a concise procedure could be automated.

Perhaps training could be changed away from training people to be robots.

An interesting item in the Lion Air report on penultimate flight
The PIC performed three Non-Normal Checklists and none contained the instruction “Plan to land at the nearest suitable airport”.
This suggest rote following of checklists without overall judgment, possibly compounded by company expectations/pressure.
Seems that when that much stuff hits the fan one would want to get down before something else happened.

[737 Driver]

I can understand a reluctance to fight the aircraft to dramatically alter the trim when the issue is not clear.

Many road vehicle crashes are made worse by tentative breaking when only full force could have helped. (Several car makers initially added brake force acceleration systems to increase partial braking towards full pressure for this reason - now augmented by radar anti-collision systems)

You can either fly the aircraft, or the aircraft will fly you. Your choice.

[Bend alot]

why don't you take some time to read up on the procedures to fly the 737. Read the official Boeing documents. Talk to 737 pilots and ask them how they are trained. Of course this will take a lot longer and require much greater effort than posting your oblivious comments but then you might be a little bit closer to actually being able to judge how these pilots performed.

Can we ask the 4 deceased 737 pilots that read up on procedures to fly a 737 (inc the FAA AD), read official Boeing documents and ask them how they were trained? I think that the surviving (currently quiet) crew would be the ones I would want to ask - anyone else is assuming lots of things.

As stated I am not a pilot but a LAME.

It is clear the pilots did not do what was needed when needed within the available conditions including limited height. But that should not have lead to a fatal crash.

Do we know who was doing the take off - Captain or F/O?

If it was the Captain should he have handed over to the FO, if so how long would you expect that decision to take?

[Loose rivets]

It's not terribly important, but when Chronus quoted on my post in #4340 , 737Driver's embedded quote had vanished leaving the impression my post was 737's. This seems to happen when cut and pasting existing quotes.

I was discussing the hidden switch removal versus it being programmed out of the equation during specific functions. As I mention, I've got a bee in my bonnet about this, since if it really had been removed, it would be an utterly vital issue. Just being programmed out is astonishing enough, and I thought 737's post was very significant - hence this ramble.

This shows the embedded quote carried forward.

https://www.pprune.org/rumours-news/619272-ethiopian-airliner-down-africa-217.html#post10455775

[RatherBeFlying]

We see several trim switch applications.

​​Why so short and ineffective?

Did the shaker interrupt the switch contact (perhaps not held down with sufficient force)?

Are pilots trained in trimming with shaker on?

Was the pilot used to or schooled in only doing short blips?

How long (or how many blips) would it take to trim out an MCAS excursion – which if recollection is correct moves the stab much faster than the trim switch?

And lastly: how well do pilots perceive stick force when the shaker is on?

[Water pilot]

To me it appears that the last crash was a case of "magenta line".

1. Stall warning and stick shaker on rotation
Solution: tried to engage the autopilot at 400 ft

2. Apparantly false stick shaker due to erroneous inputs + unreliable airspeed
Solution: tried to engage the autopilot at 600 ft

3. Still stick shaker due to erroneous inputs from left side
Solution: finally succeeded to engage the left autopilot at 1000 ft

4. Aircraft is grossely out of trim and in an overspeed condition, making it hard to fly
Solution: tried to engage the autopilot


We just don't know their motivation. It had been widely reported in the media and elsewhere that MCAS was only active during manual flight, so a pretty obvious (but unfortunately incorrect) response would have been to turn the autopilot on. If it solved the problem, then a much better solution than dinking around with the manual wheel at low altitude.

Note that in your response, you are assuming that the pilots should have known which side the erroneous inputs came from or that the cause of their troubles was an erroneous AOA gauge. For some reason our brains have a really difficult time with 20/20 hindsight, a fact that is detrimental to human factors design. Almost every problem that I ever solved (and that was a big part of my job) was painfully obvious in hindsight. As I said earlier, my company liked to challenge potential hires with difficult puzzles. I ended up getting into the HR loop and was cursed with a good memory. It was almost funny how my fellow employees would tear down candidates for failing to solve puzzles that I clearly recalled them failing just a few years before...

[wonkazoo]

Reading the back and forth on the conundrum of “Pilots completely at fault for being stupid” as set against “Pilots completely not at fault because Boeing designed a $hit system,” and I’ve decided to take a stand. Apologies in advance as this is long, but trust me- it is worth it.

Of all of you out there who have posted here- whether with a desire to blame the pilots entirely or the opposite, how many of you have actually experienced an imminent, binary and life-threatening emergency in your airplane?? One that is so explicit you will either get it right or you will die?? And you have maybe 30 seconds to make that choice.

My guess is the list of aviators who can answer honestly that they have been at that threshold of death is very very small.

I am on that list. And I survived, despite making bad choices along the way.

I share this story because I want people to understand once and for all that while it is fine to offer that the pilots could have done better (they totally could have) the root cause of the MAX crashes was one of design, and human failures only built on that edifice to achieve the final outcome.

I also share this story because I want to try to explain to everyone here, in terms we can all understand, what it is really like when your known world explodes and you have to improvise in order to survive.

In June of 1996 I was in a very high performance unlimited category biplane named the Goshawk. (N345RM) I had departed Livermore CA several minutes earlier and was headed to a legal practice box adjacent to the Tracy airport. While over the Altamont hills at an indicated altitude of 4000MSL I began warming up by pulling to a 45 degree upline and doing snap rolls to the right. I did this once or twice. On the third attempt, once again at approximately 4000+MSL I initiated the snap roll to the right and hit hard left rudder as the wings returned to level to stop the autorotation. When I did this the left rudder pedal/bar shot away from my foot instead of providing actual resistance. The left rudder cable had snapped.

The airplane (which was by design dynamically unstable) paused its rotation for a moment and then began again violently to the right, probably at about 360 degrees per second. And here’s where the chair-jockeys don’t get it. I probably went two or three full revolutions before my mind could accept what I already knew had happened. I immediately pulled power, but the aircraft was already entering a nose-down spin- at a rotational rate of at least 360 degrees per second.

The ROD of a spinning aerobatic biplane is pretty steep, probably on the 1500-2000FPM range. I checked my altimeter, saw I was descending through 4,000 feet and decided to try to recover the airplane before bailing out. AND HERE IS THE IMPORTANT POINT: BECAUSE I REFUSED TO ACCEPT THAT THE AIRPLANE WAS COMPLETELY EFFED I would nearly die. My mind knew before then, as it knows now, that if you put a Pitts-like airplane into an autorotational state the only thing that is going to get it out is opposite yaw. With no rudder THERE CANNOT BE ANY OPPOSITE YAW!! I had thousands of hours in similar aircraft, I was an unlimited category competition aerobatic pilot and instructor, and yet when faced with the obvious I could not process it quickly enough, despite having the evidence staring me squarely in the eye, to react quickly enough to prevent me from nearly dying.

So I frittered away precious moments trying to use opposite yaw via ailerons, shots of engine thrust, hell I might have even prayed, I don’t know. What I know now is I could have done better. What I also know now, and somehow managed to forget then, was that I was over the Altamont. When I saw 4000’MSL and thought “OK, I’ve got time to play with this” the reality was I was over a hill- that was 2134’ high. Tracy- just 20 miles away and where I was headed sits at 193’ MSL.

In my mind, because I was stupid overwhelmed, or just unable to process everything being thrown at me I had maybe 3500-4000’ to play with. So I could spend 30 seconds fighting the airplane to try to recover it before I had to bail.

In reality I had less than 2000’ before I would be dead.

I spent probably ½ to ¾ of the real time I had to get out of the airplane in it- fighting to try to save it, and I did this by deliberately ignoring what I already knew (I had lost rudder control completely) what I should have known (I was over the Altamont) and what I should have accepted (I had to go- the Goshawk was not going to survive this, the only real question was would I??)

I obviously did reach the (already foregone but stubbornly ignored by me) conclusion that the airplane was unrecoverable and decided to bail out- which is an interesting concept in a stable spinning airplane. I undid my harnesses as I had practiced, and I fought my way out of the airplane- pinned against the left side of the cockpit coaming by the rotational g-forces before eventually getting enough of my upper body into the slipstream that I was basically yanked out of the airplane. I was falling in a fetal position, thought about waiting to pull the ripcord, said eff-it and pulled, and after the shocking introduction to my first and (so far) only canopy opening was struck by the sound of the airplane smacking into the ground just a second or two later. Future calculation efforts would show that my chute opened between 134 and 200 feet above the ground, which at that rate of descent equaled a couple of seconds at best.

Surviving that incident has given me some small window of insight into what happens when your comfy world devolves in seconds into one where you know you are about to die.

The biggest lesson, and the greatest ego-killer was simple: I didn’t respond nearly as I would have hoped I would. It took me countless seconds to register the fact of the failure. I knew as soon as the pedal fired away from my foot what had happened. But my mind simply refused to accept that reality for some short period of time. The second error was equally simple: I thought I was the hero pilot (Neil Williams etc…) who would bring my crippled plane back to the airport, thereby saving the day. That thought nearly cost me my life, as I wasted precious seconds performing an absolutely useless dance of fancy “airmanship” that did nothing but allow my airplane to bring me closer and closer to the ground with every moment.

And now to the main point of this entirely too-long post: For those of you who suppose you will see everything clearly and “FTFA” when your own fatal opportunity presents itself please hear me when I say this: YOU WILL NOT!! The question that will determine your survival is how quickly will you move past that initial shock and be able to function properly again. In my case it was a single (albeit fatal) failure. I was extremely well trained, averse to panic-driven responses, and well-able to handle the emergency I had been presented with. Yet I wasted probably a full minute in an airplane I had no business being in any longer.

In the 737 crashes it was a cascade of failures. My own- very rare life experience tells me that those pilots had little chance given the stressors they were working under, as would the rest of you. These are not the words of someone who doesn’t know what it’s like. I’ve been there. I lived. So please trust me when I tell you that your vaunted talents will wither to nothing if someday you are in this unfortunate position. At best you will be semi-functional, at worst you will be functionally useless.

What you will not be, in any context, is a hero who defies these realities.

Final note: This isn’t about placing blame on anyone. Boeing designed an airplane with a crap system that had random and unmonitored control over the single most important control surface of the aircraft. The FAA paved the way for certification of the airplane, and once in the hands of pilots that airplane not once, but twice flew itself into the ground. (The pilots didn’t- it was MCAS that did, and that’s an important fact to take note of…) You can blame the pilots all you want, but it was the airplane itself that had a failure mode that required the pilots to be perfect or die. Boeing had years to create a functioning system that would not put the pilots in this position and they failed to create one. So the two (six really) pilots were left to defend themselves against an airplane that was trying to kill them. Four failed in that endeavor, and they have my utmost respect and gratitude.

Only those who have walked the path and survived can understand the fine line between winning and dying- which is why I have posted this ridiculously long post tonight.

Sorry for the sermon, just tired of reading the constant back and forth about who we should blame.

Link to the Final on my incident: Well despite being a member for years I haven't reached the vaunted 10-post threshold for posting URLs. Search "NTSB June 17, 1996 N345RM" for the final report.

Regards,
dce

[Jetman346]

Dce

that is an excellent post and so true

[Bend alot]

Reading the back and forth on the conundrum of “Pilots completely at fault for being stupid” as set against “Pilots completely not at fault because Boeing designed a $hit system,” and I’ve decided to take a stand. Apologies in advance as this is long, but trust me- it is worth it.

Of all of you out there who have posted here- whether with a desire to blame the pilots entirely or the opposite, how many of you have actually experienced an imminent, binary and life-threatening emergency in your airplane?? One that is so explicit you will either get it right or you will die?? And you have maybe 30 seconds to make that choice.

My guess is the list of aviators who can answer honestly that they have been at that threshold of death is very very small.

I am on that list. And I survived, despite making bad choices along the way.

I share this story because I want people to understand once and for all that while it is fine to offer that the pilots could have done better (they totally could have) the root cause of the MAX crashes was one of design, and human failures only built on that edifice to achieve the final outcome.

I also share this story because I want to try to explain to everyone here, in terms we can all understand, what it is really like when your known world explodes and you have to improvise in order to survive.

In June of 1996 I was in a very high performance unlimited category biplane named the Goshawk. (N345RM) I had departed Livermore CA several minutes earlier and was headed to a legal practice box adjacent to the Tracy airport. While over the Altamont hills at an indicated altitude of 4000MSL I began warming up by pulling to a 45 degree upline and doing snap rolls to the right. I did this once or twice. On the third attempt, once again at approximately 4000+MSL I initiated the snap roll to the right and hit hard left rudder as the wings returned to level to stop the autorotation. When I did this the left rudder pedal/bar shot away from my foot instead of providing actual resistance. The left rudder cable had snapped.

The airplane (which was by design dynamically unstable) paused its rotation for a moment and then began again violently to the right, probably at about 360 degrees per second. And here’s where the chair-jockeys don’t get it. I probably went two or three full revolutions before my mind could accept what I already knew had happened. I immediately pulled power, but the aircraft was already entering a nose-down spin- at a rotational rate of at least 360 degrees per second.

The ROD of a spinning aerobatic biplane is pretty steep, probably on the 1500-2000FPM range. I checked my altimeter, saw I was descending through 4,000 feet and decided to try to recover the airplane before bailing out. AND HERE IS THE IMPORTANT POINT: BECAUSE I REFUSED TO ACCEPT THAT THE AIRPLANE WAS COMPLETELY EFFED I would nearly die. My mind knew before then, as it knows now, that if you put a Pitts-like airplane into an autorotational state the only thing that is going to get it out is opposite yaw. With no rudder THERE CANNOT BE ANY OPPOSITE YAW!! I had thousands of hours in similar aircraft, I was an unlimited category competition aerobatic pilot and instructor, and yet when faced with the obvious I could not process it quickly enough, despite having the evidence staring me squarely in the eye, to react quickly enough to prevent me from nearly dying.

So I frittered away precious moments trying to use opposite yaw via ailerons, shots of engine thrust, hell I might have even prayed, I don’t know. What I know now is I could have done better. What I also know now, and somehow managed to forget then, was that I was over the Altamont. When I saw 4000’MSL and thought “OK, I’ve got time to play with this” the reality was I was over a hill- that was 2134’ high. Tracy- just 20 miles away and where I was headed sits at 193’ MSL.

In my mind, because I was stupid overwhelmed, or just unable to process everything being thrown at me I had maybe 3500-4000’ to play with. So I could spend 30 seconds fighting the airplane to try to recover it before I had to bail.

In reality I had less than 2000’ before I would be dead.

I spent probably ½ to ¾ of the real time I had to get out of the airplane in it- fighting to try to save it, and I did this by deliberately ignoring what I already knew (I had lost rudder control completely) what I should have known (I was over the Altamont) and what I should have accepted (I had to go- the Goshawk was not going to survive this, the only real question was would I??)

I obviously did reach the (already foregone but stubbornly ignored by me) conclusion that the airplane was unrecoverable and decided to bail out- which is an interesting concept in a stable spinning airplane. I undid my harnesses as I had practiced, and I fought my way out of the airplane- pinned against the left side of the cockpit coaming by the rotational g-forces before eventually getting enough of my upper body into the slipstream that I was basically yanked out of the airplane. I was falling in a fetal position, thought about waiting to pull the ripcord, said eff-it and pulled, and after the shocking introduction to my first and (so far) only canopy opening was struck by the sound of the airplane smacking into the ground just a second or two later. Future calculation efforts would show that my chute opened between 134 and 200 feet above the ground, which at that rate of descent equaled a couple of seconds at best.

Surviving that incident has given me some small window of insight into what happens when your comfy world devolves in seconds into one where you know you are about to die.

The biggest lesson, and the greatest ego-killer was simple: I didn’t respond nearly as I would have hoped I would. It took me countless seconds to register the fact of the failure. I knew as soon as the pedal fired away from my foot what had happened. But my mind simply refused to accept that reality for some short period of time. The second error was equally simple: I thought I was the hero pilot (Neil Williams etc…) who would bring my crippled plane back to the airport, thereby saving the day. That thought nearly cost me my life, as I wasted precious seconds performing an absolutely useless dance of fancy “airmanship” that did nothing but allow my airplane to bring me closer and closer to the ground with every moment.

And now to the main point of this entirely too-long post: For those of you who suppose you will see everything clearly and “FTFA” when your own fatal opportunity presents itself please hear me when I say this: YOU WILL NOT!! The question that will determine your survival is how quickly will you move past that initial shock and be able to function properly again. In my case it was a single (albeit fatal) failure. I was extremely well trained, averse to panic-driven responses, and well-able to handle the emergency I had been presented with. Yet I wasted probably a full minute in an airplane I had no business being in any longer.

In the 737 crashes it was a cascade of failures. My own- very rare life experience tells me that those pilots had little chance given the stressors they were working under, as would the rest of you. These are not the words of someone who doesn’t know what it’s like. I’ve been there. I lived. So please trust me when I tell you that your vaunted talents will wither to nothing if someday you are in this unfortunate position. At best you will be semi-functional, at worst you will be functionally useless.

What you will not be, in any context, is a hero who defies these realities.

Final note: This isn’t about placing blame on anyone. Boeing designed an airplane with a crap system that had random and unmonitored control over the single most important control surface of the aircraft. The FAA paved the way for certification of the airplane, and once in the hands of pilots that airplane not once, but twice flew itself into the ground. (The pilots didn’t- it was MCAS that did, and that’s an important fact to take note of…) You can blame the pilots all you want, but it was the airplane itself that had a failure mode that required the pilots to be perfect or die. Boeing had years to create a functioning system that would not put the pilots in this position and they failed to create one. So the two (six really) pilots were left to defend themselves against an airplane that was trying to kill them. Four failed in that endeavor, and they have my utmost respect and gratitude.

Only those who have walked the path and survived can understand the fine line between winning and dying- which is why I have posted this ridiculously long post tonight.

Sorry for the sermon, just tired of reading the constant back and forth about who we should blame.

Link to the Final on my incident: Well despite being a member for years I haven't reached the vaunted 10-post threshold for posting URLs. Search "NTSB June 17, 1996 N345RM" for the final report.

Regards,
dce


Thanks for sharing your brush with the dark side.

A couple of serious questions if you do not mind.

During your event did pitch and power enter your mind?

Were you a airline pilot or just aerobatics?

How long did you actually spend trying to fight it, and how long did it feel like you fought it (I expect they are not the same answer).

[DaveReidUK]

Link to the Final on my incident: Well despite being a member for years I haven't reached the vaunted 10-post threshold for posting URLs. Search "NTSB June 17, 1996 N345RM" for the final report.

Final report.

[wonkazoo]

Thanks for sharing your brush with the dark side.

A couple of serious questions if you do not mind.

During your event did pitch and power enter your mind?

Were you a airline pilot or just aerobatics?

How long did you actually spend trying to fight it, and how long did it feel like you fought it (I expect they are not the same answer).

As I wrote- I tried to use thrust (power) to bump it out of it's spin. When a dynamically unstable airplane is in auto-rotation pitch alone doesn't have the ability to recover the aircraft. It can tighten or loosen the auto-rotation by virtue of decreasing or increasing the AOA (Hmmm, have I read about AOA recently??), but pitch authority alone (of which there was tons in this airplane) cannot overcome the autorotative state as it does not affect yaw, which is the critical factor in a stabilized spin. (Inside wing stalled, outside wing flying...) I did try pro-spin and anti-spin aileron with the power changes. Frankly I genuinely thought I could bump it out of it's stable autorotative state. Which was my pilot-ego speaking louder than my science-pilot self.

"Airline pilot or just aerobatics?" Well that's an interesting question, but I've never flown heavy iron, nor have I suggested I have. But I did somehow survive roughly 4400 hours of PIC time in an immense variety of airplanes and helicopters, each of which obeys the same exact physics as a 737 Max-8.

I cannot tell you how long I spent trying to recover the airplane (as opposed to fighting it). IN round numbers when I realized what had happened I looked at the altimeter, saw something around 4000' MSL and thought "I have some time." Roughly speaking I was on the ground a minute or a minute and a half later.

[Alchad]

Wonkazoo

Don't apologise for the length, really excellent post, thank you.

Regards - and respect.

Alchad

[GordonR_Cape]

Final report.

There is also a summary of the accident here: https://aviation-safety.net/wikibase/wiki.php?id=133835

Edit: The dry report contains nothing like the first-hand version in this thread:
attempts at regaining control were unsuccessful

[wonkazoo]

One more quick note before I totter off to bed.

We all like to think of ourselves as calm and cool. The Chuck Yeager persona etc.

I really hope you all hear what I am trying to say here- more than I ever have before.

When I landed awkwardly, (I tried to flare my round chute) I was then dragged for a couple hundred feet or so as the winds were blowing around 15KT and a chute is alas a big kite. I finally got it collapsed enough to unbuckle the harness and stop the whole sad circus in its tracks.

And there I lay, in the dry grass of a California summer, on the container of my parachute and harness, panting like a dog who has run miles, and looking at my hands as my pulse thudded through my fingers in a way I've never felt before or since.

My mind would take years to process that I had just been in a knife fight for my survival, but my body knew exactly what had happened. I am known for being calm, especially when stuff gets silly. What most people don't know is that I have lain helpless on my stomach, with three fractured vertebra, staring at my hands all while panting uncontrollably.

Because despite being calm I almost ran out of answers. (Actually I did run out of answers- which helped as the only option was to bail out- much to my family's presumed happiness.)

We like to see ourselves as heroes- who will always do the right thing when the chips are down.

The reality as far less noble. Which is why compassion for those who were put in a situation just like mine, but who were so minutely less fortunate, is completely appropriate,

Cheers-
dce

[Bend alot]

As I wrote- I tried to use thrust (power) to bump it out of it's spin. When a dynamically unstable airplane is in auto-rotation pitch alone doesn't have the ability to recover the aircraft. It can tighten or loosen the auto-rotation by virtue of decreasing or increasing the AOA (Hmmm, have I read about AOA recently??), but pitch authority alone (of which there was tons in this airplane) cannot overcome the autorotative state as it does not affect yaw, which is the critical factor in a stabilized spin. (Inside wing stalled, outside wing flying...) I did try pro-spin and anti-spin aileron with the power changes. Frankly I genuinely thought I could bump it out of it's stable autorotative state. Which was my pilot-ego speaking louder than my science-pilot self.

"Airline pilot or just aerobatics?" Well that's an interesting question, but I've never flown heavy iron, nor have I suggested I have. But I did somehow survive roughly 4400 hours of PIC time in an immense variety of airplanes and helicopters, each of which obeys the same exact physics as a 737 Max-8.

I cannot tell you how long I spent trying to recover the airplane (as opposed to fighting it). IN round numbers when I realized what had happened I looked at the altimeter, saw something around 4000' MSL and thought "I have some time." Roughly speaking I was on the ground a minute or a minute and a half later.
Cheers, was just some questions based on some posts on this thread.

Far from your experience, I have had a couple of near departed events in my life and thinking rationally at the time is somewhat fuzzy.

I have also witnessed a few fiery actual crashes both fixed wing and a rotary (I expect GF rights played a big part in the rotary one S269 C to D) - very strange how different we react at that time. The pilot that was in a bad way and passed soon after lead us to the problem.

Also involved very closely with a loss of aircraft (RIP) on a private fly away - again very different the way people acted and after recalled the event during personal chats and the ATSB investigation.

Thanks for detailing your account.

[TheEdge]

The reality as far less noble. Which is why compassion for those who were put in a situation just like mine, but who were so minutely less fortunate, is completely appropriate,

Cheers-
dce

Thanks Sir for this. Really.

[wonkazoo]

There is also a summary of the accident here: https://aviation-safety.net/wikibase/wiki.php?id=133835

Edit: The dry report contains nothing like the first-hand version in this thread:

One quick note/mea culpa:

The "Pushed himself back into his seat' charade was because I was (technically) (Well really) performing aerobatic maneuvers within 4NM of an airway. Which meant if I admitted to deliberately entering the maneuver I could be busted by the feds. Since I had to hike a couple of miles back to civilization (with one sneaker and a sock) I had plenty of time to find a rational explanation for how my airplane entered into an autorotative state without doing actual aerobatics.

Second note: The report is inaccurate and confusing when it says I was in the box when the failure occurred. A simple look at the map will tell you that the failure occurred over the Altamont.

Last Note, and a good one: Our family (Including my 10 and 12 year-olds) is going to go to the crash site on June 17th. The actual location is a bit unknown as it was in the middle of a ton of grass, some hillsides, two ponds, and a gazillion cows. But the image I first saw when I looked up from my hands will never leave me, and the wreck can't be far from there. Granted most pieces were removed 20 years ago, but the engine case was buried up the the middle of the last bank, so I'm betting if we look hard enough we'll find evidence of the event.

All of which is simply amazing. I went from seconds separating me from life, to a family and a life unknown.

Lucky am I...
dce

[MD80767 Driver]

Thank you so much Wonkazoo. If you don't mind, I will copy your post - and send it to some of my Hot Shot buddies - yeah, still buddies - who still are adament that they would have saved the Lion Air and ET flights. Thank you Sir. From a 16k hours Airline guy, who doesn't know if I could have done better...

[BleedingOn]

Great post dce. Should be mandatory reading on any human factors refresher

[oggers]

My guess is the list of aviators who can answer honestly that they have been at that threshold of death is very very small.

A small proportion but not a small number. Everyone who has ever ejected, bailed, or faced a major malfunction could be asked and most likely have a range of opinions on the human factors of ET302.

[Bend alot]

A small proportion but not a small number. Everyone who has ever ejected, bailed, or faced a major malfunction could be asked and most likely have a range of opinions on the human factors of ET302.
With a common theme - it was not easy and I made mistakes and luck played a part in many of them - but any with ejection seats are never in the position of the ET 302 crew and even Wankazoo ( opps wonkazoo is correct - embarrassing mistake thanks for the PM's I will live with it.) had a "bail" option in real life.

A major malfunction is what an engine failure? every Tom Dick and Harry practice that on takeoff and very often!

[PerPurumTonantes]

Average professional pilots even below average professional pilots should note and correct out of trim flight. This is C-172 stuff and is not complicated.
Way back in training we were in a C172 about to take off. I'd skipped a checklist item - "autopilot off". Instructor came down on me hard for that one := He told me the story of a fatal crash at Leicester UK where pilot left AP on.

"Initially, until about 100 feet agl the take-off appeared normal but then the aircraft adopted an ever increasing nose-high attitude which culminated in a gentle left roll at about 300 feet agl before the aircraft's nose dropped sharply. It seemed to the aero club witnesses that the aircraft had stalled in a markedly nose-up attitude. After what appeared to be an attempted stall recovery at about 100 feet
agl, it dived into the ground whilst rolling left with the engine still running"
...
"During the ground evaluation tests it was noticed that if the ALT button was pressed, the autopilot
engaged... About three to four seconds
later, the elevator trim commenced winding on nose-up trim until it reached maximum deflection;
this took about 18 seconds".

HAL can get at you even in a 172.

https://assets.publishing.service.gov.uk/media/5422ec04e5274a13170000d5/dft_avsafety_pdf_501522.pdf (https://www.google.com/url?sa=t&source=web&rct=j&url=https://assets.publishing.service.gov.uk/media/5422ec04e5274a13170000d5/dft_avsafety_pdf_501522.pdf&ved=2ahUKEwiPvc6kw-3hAhVfAWMBHQU1ChIQFjAdegQIARAB&usg=AOvVaw1VIaAPDfdmpAMW6j1W3DN4)

[Loose rivets]

wonkazoo, thanks for a thought provoking break from the regular arguments. Refreshing to have one's mind taken so vividly to that scene. Talking of minds.


A couple of times I've posted about getting into the minds of the three MAX crews. I've tried to paint the picture of the chaos and mental confusion that was probably - and I mean, probably - taking place.

Strangely, if feel Could've done's and should've done's are fine for analytical discussion . Yes, they're often unkindly critical, but without them we don't have both sides of the most fundamental part of this long thread: the argument between both camps. More or less the performance of the four pilots, V FAA and Boeing's behaviour.

I protested that the months of hindsight invalidates any true judgement we may feel compelled to put forward against the pilots.

Getting into the mind of an average pilot, whatever that might be these days. One thing's for sure, it's not one that's had his senses sharpened by months of focussed discussion on this specific crisis, and not necessarily comparable to some of the pilots on here that have a wealth of experience on a wide range of Boeing products.

I further expressed some astonishment at what I described as the dichotomy of opinions between even the highly experienced PPRuNe posters.

[Bergerie1]

wonkazoo,

Thank you for your excellent post, no need to apologise for its length. Like you, I have been to 'the edge' very early on in my airline pilot career, it made me think a whole lot differently about flying - to my eventual benefit. Indeed, yes, the brain does become scrambled for a while when something startling, sudden and frightening occurs. Read my link and stop for a moment and think how foolish we all were to switch off the main flight instruments in the middle of what was probably a spiral dive.
IFR conditions on the flight deck (http://vc10.net/Memories/IFRcockpit.html)

It takes time to collect your thoughts and start to react correctly. I was the co-pilot. We survived and it made me very humble about these things ever afterwards. Armchair quarter backs should spare a thought for those caught up in such events and say to themselves,"There but for the grace of God go I."

And it applies to Sky Gods too!

[737 Driver]

Wonkazoo,

Appreciate the comments. Understanding the human reaction to an aircraft emergency is a very important part of examining these incidents. You're right, that it really isn't a case of Boeing messed up or the pilots messed up or the regulators messed up or the maintenance folks messed up. All those parts came together at the same time to cause these accident. However, by they same token, we can't simply sit back and say Boeing needs to fix their design, the FAA needs to strengthen their oversight, the airlines have to do a better job at training, and then turn a blind eye to what, we as professional pilots, ought to be doing to address obvious shortcomings in airmanship. And we can't address those shortcomings unless we acknowledge that those shortcomings were present in these accidents.

In my aviation career, I've had three incidents where if I didn't make the right choices in a timely manner, then a very bad outcome would have resulted. The most notable was an engine failure in a single-engine aircraft that culminated in a deadstick ILS approach to the runway with 300-1 weather. Yes, luck was involved in that there was an airport close enough to navigate to, but luck didn't land the plane. I don't say this to pat myself on the back, but to simply to say that I've been there. You're right in that the initial wave of emotions and disbelief can be enormous and potentially paralyzing. I've also made some embarrassing mistakes in my career that if not caught by my trusty First Officer, could have devolved into something unpleasant. Mistakes happen and humans err, but that does not mean we just throw up are arms and say there's nothing to be done.

I've said before that when I was an instructor pilot, I could take just about any well-adjusted adult and teach them the basics of flying and that they would be safe enough on a VFR day if nothing went wrong. Similarly, there are lots of people who can be taught the systems management approach to flying, and as long as nothing happens too quickly and the problem is well-known or the solution is covered by some non-normal checklist, then they will do just fine.

Here's the cold reality of these accidents: Things will happen that aren't on the checklist. They can happen quickly. Crew competency matters, and I do mean "crew" because the Captain can't do it all himself when things go bad. Basic airmanship skills matter. The ability to think under pressure matters. The ability to prioritize matters. Ultimately, these planes were flyable using some pretty basic airmanship skills, but that did not happen. Perhaps one day the aircraft and all the processes that touch a flight will be made so completely fault tolerant that these things don't matter. However, when that future becomes reality, airlines won't need professional pilots anymore, will they?

Yes, I'm being hard on the crew, just as I'm being hard on Boeing and the FAA and the airlines. It can be a hard business, and people die when we don't get it right. That being said, I've seen no evidence that anyone was intentionally malicious or careless. The human factor element touches every part of these accidents from the aircraft designers, to the supervisors, to the regulators, to the airline managers, and all the way to the flight crew. We know that there were multiple mistakes by multiple humans, and now it is incumbent on us to ask what could have been done differently. We do not do this so we have the luxury to say WE could have prevented these accidents, but to make the entire chain of causation more resilient and safer.

PPRUNE is not an online forum for Boeing or the FAA or airline management. We can point fingers, but we can't really fix their issues. PPRUNE, however, is a forum for professional pilots, so we can certainly discuss what ought to be done when we see evidence that points to lapses in airmanship. If some of the participants want to take the position that there is nothing to be done, that we merely have to accept that some of our number are going to succumb to the pressures induced by an unexpected aircraft state, fail to execute well-established procedures and/or apply basic airmanship skills, I am not sure what else I can say.

IMHO, what I think would be more beneficials is to move past the shock and denials and the strong desire to defend one of our own and look at the particular chain of causation that led to these crews not being able to perform to the standards of a professional pilot when lives were at stake.

[Bergerie1]

737 Driver,

You are right too. Every part of that chain of human mistakes needs to be examined - manufacturers, regulators, airlines, trainers, accountants, managers and pilots. The pilots are the last link in that chain and in these last two accidents they were lacking too. As professional pilots we must strive for and achieve high standards, and, let's face it, most do.

[HundredPercentPlease]

Another issue is, if these accidents were preventable by carrying out the required Boeing procedures or by applying basic flying skills respectively, despite MCAS activating.

When I was trained on the 737 (classic and NG), the stab trim runaway was a runaway - where the trim wheel ran continuously. We would identify it as a runaway, because it was continuously running, and flick the switches.

1. MCAS activation is not continuous, it's bursts.
2. The 737 trim system likes to provide bursts of random trim at certain times (STS) so bursts are considered normal.

This is why the Boeing excuse "they should have done the runaway stab QRH to fix the MCAS problem" is a load of utter nonsense. 737 Driver - pinning this on lack of airmanship will costs lives in the future.

[Bergerie1]

HundredPercentPlease,

I don't know the 737 but I used to fly 707s. The stab trim runaway drill was predicated on continuous movement as you say. I imagine the bursts of STS activity made these movements appear normal and thus mask the MCAS bursts too. All very confusing.

[jimmyjetdriver]

Can I just highlight that the F/O had 200hrs experience. I didn't get a commercial pilots licence until I had flown 230 hours and didn't fly jets until I had 1800hrs. The company that I flew 737's for in the UK in the early 1970's required 2000 hours before offering a job in the right hand seat.

This incident was to all intents and purposes a single pilot operation.

Absolutely spot on. At 200 (300 according to ET) hours, you are just along for the ride. The CA himself may have never flown anything outside of ET, certainly not old and broken airplanes from the past. It really bothers me that to this day, I sometimes look over at the FO for ideas or help in doing mental math, and he has nothing to contribute. These aircraft are certified for a minimum of two experienced pilots, not one instructor and one student. Ridiculous.

12,000 hours as captain of 727/57/67, I still rely on my highly experienced F/O's to feed me as much advice as they can.

[hans brinker]

When I was trained on the 737 (classic and NG), the stab trim runaway was a runaway - where the trim wheel ran continuously. We would identify it as a runaway, because it was continuously running, and flick the switches.

1. MCAS activation is not continuous, it's bursts.
2. The 737 trim system likes to provide bursts of random trim at certain times (STS) so bursts are considered normal.

This is why the Boeing excuse "they should have done the runaway stab QRH to fix the MCAS problem" is a load of utter nonsense. 737 Driver - pinning this on lack of airmanship will costs lives in the future.

I think we disagree where a burst ends and continuously starts. Only been in the jumpseat of the 737, but I would be wildly surprised if STS would ever trim more than a second or two. Having the trim wheel run for ten seconds is way more than a burst. Having said that I can totally see the pilots not realizing what is going on amidst the whole set of stall warning/stick shaker/UAS indications. MCAS should never have been certified using only one AOA at a time, and I feel the same goes for the stall warning/stick shaker, there should at least be an easy way to cancel the alert if the warning is spurious.

[Lonewolf_50]

Can I just highlight that the F/O had 200hrs experience. I didn't get a commercial pilots licence until I had flown 230 hours and didn't fly jets until I had 1800hrs. The company that I flew 737's for in the UK in the early 1970's required 2000 hours before offering a job in the right hand seat.

This incident was to all intents and purposes a single pilot operation. This airline isn't alone in setting up that situation.
It does not help that the captain was only recently transitioned to the new aircraft, and the already-mentioned-a-few-hundred-times issues with "just what was in the differences training?" was hardly a robust aircraft systems course. That their best efforts were not good enough points, in my view, a finger at the system writ large: training, currency, company policies on training (and others) and of course the aircraft system itself. What is to me the most worrying is that with the comparatively recent Lion Air crash, this crew was, it seems, neither prepared nor trained on how to deal with that problem.
That right there, it seems to me, is where the entire system let these two pilots down. The "system" doesn't learn, and / or does a poor job of passing on "lessons learned."
Deni, a few pages back, points to the AoA signal getting to the flight computer as being a detail worthy of very thorough resolution. With the Lion Air ending up in the sea, some evidence of how that signal went sour may have been lost. In this crash, granted, there was a fire, perhaps some evidence of that signal's path, and it's possible sources of corruption, may be more clear.
I sincerely hope that Beoing's team is, along with their various test flights, putting a high magnification glass on the entire path of the AoA signal from vane to computer, and focues on how and where those signals can get dirty/contaminated. I experienced a variety of strange things happening in aircraft over the years due to electrical signals going astray or strange. Were stray trons a root cause?
We'll see.

[737 Driver]

When I was trained on the 737 (classic and NG), the stab trim runaway was a runaway - where the trim wheel ran continuously. We would identify it as a runaway, because it was continuously running, and flick the switches.

1. MCAS activation is not continuous, it's bursts.
2. The 737 trim system likes to provide bursts of random trim at certain times (STS) so bursts are considered normal.



Honest question: How long does a trim wheel have to spin before you deem it "continuous" and thus subject to intervention by the pilot?

In the case of Ethiopian, the MCAS input was not like the normal Speed Trim you see during takeoff. If you take a look at the DFDR traces of the automatic trim before the flaps were retracted, you can see what these inputs look like. Short and seemingly random inputs.

When MCAS activated, it ran the trim nose down for 9 continuous seconds. Please count that out to yourself. MCAS moved the stab about 2.5 degrees. That would be about 37 spins of the flight deck trim wheel. Please imagine that white stripe on the trim wheel making 37 trips passed the Captain's knee. All this time, the Captain was holding the yoke and must have felt the changing trim pressures. This happened TWICE (one other MCAS input was interrupted by the pilot trimming nose up). Ultimately, it wasn't even the 8122-hour Captain who suggested that the trim cutout switches be used - it was the 361-hour First Officer.

So honestly, just how long does the stab have to continuously run before a fully qualified 737 type-rated Captain determines that he has runaway stab trim?

[jimmyjetdriver]

Reviewing the charts, can someone explain to me why the N1 percentage seems to be 95-100%? This aircraft seems to be going at a very high IAS. No wonder manual trim was so difficult. Rule number 1, fly the aircraft.

[gums]

Salute!

Thanks a lot, Wonk. Best post in a very long time.

Maybe some of the “Sky Gods” here would think about some things.

And I support your criticism of Big B and FAA and so forth for letting the plane fly we lowly proles without satisfying basic aerodynamic FAR requirements. I would even go so far as to claim the Airbus FBW models could be flown in “direct law” and behave as required. After all, the AF447 debacle showed how stable the plane was despite the best efforts of the crew to keep it stalled.

Gums ......

[HundredPercentPlease]

Gums,

As I understand it, when designing the A320 Airbus toyed with the idea of reduced stability, citing FBW as the "excuse". The whole world raised a regulatory eyebrow and Airbus designed a fully stable aircraft.

Ironically, Boeing designed a less than stable aircraft with a bit of bolt on, undocumented FBW, and the world continued to rotate, until two crashed.

[HundredPercentPlease]

). Ultimately, it wasn't even the 8122-hour Captain who suggested that the trim cutout switches be used - it was the 361-hour First Officer.



The reason people are bashing your skygod/airmanship analysis is hidden in your statement above.

Why do you think the captain didn't get it, but the FO did?

Really, why?

As so many are saying, this is HF. Think: volume of input and processing.

A final thought: do you think that if the ET crew had trained this scenario in the sim, then when it happened for real then they would have been fine? The comfort of the sim helps recognition, which reduces processing, which allows improved performance through lack of overload. The max is a dog, but Boeing would have got away with it (again) if pilots had been sim trained.

These pilots were overloaded, they weren't adequately prepared and the aircraft is flawed.

[737 Driver]

.
These pilots were overloaded, they weren't adequately prepared and the aircraft is flawed.

Agree 100%. So what should be done to insure the next crew is not overloaded and unprepared the next time they are handed a flawed, but still flyable, aircraft?

Because there will be a next time.

[HundredPercentPlease]

Simple.

Remove the flaw. Either remove the aerodynamic stability problem or make the FBW fix a proper one (like an Airbus, triple inputs, 14 computers, multiple layers of automatic or selectable degraded flight modes).

Train the pilots. If a single failure (here AoA) causes a monster, then prepare the pilots by training.

As someone who has moved back and forth, twice, between the 737 and A320, I can't begin to describe how lowly I view the Renton tractor. Boeing made a flawed aircraft and failed to mandate sufficient training. The pilots are as much victims as the passengers. No doubt at all.

[PerPurumTonantes]

Wonkazoo,
Ultimately, these planes were flyable using some pretty basic airmanship skills, but that did not happen.

No.
Look I agree with most of what you're saying. Good airmanship, hand flying practice, all the other great points.

But this is different to any other aircraft system failure that I can think of.

Eg loss of pitot. Loss of static. Engine fire. "QF32" uncontained failure causing multiple control system failures. Flap/slat wrong config at takeoff. Dual engine out after bird strike... Etc.

These are all single events that put the aircraft in a new and interesting state. Now use good airmanship to recover. Fine.

Why is MCAS different?
1) It's intermittent. Not just a single event. Pops up unexpectedly for a few seconds then disappears. These are always the hardest faults to diagnose.
2) It's insidious - hidden by noise and by human expectation (hiding in plain sight - bursts of trim are normal).
3) It's fast - it can put you in serious trouble in a few seconds flat
4) Like a bacterial complication to a viral infection, it creeps in and hits you when you're dealing with another problem (airspeed unreliable/stick shaker)
I'm not saying that the ET302 pilots had no room for improvement. Like you I think their repeated autopilot engagement is a red flag. But dealing with MCAS failure is in test pilot league, not 'basic airmanship skills'.

[gums]

Salute!

@ 100% We went thru a lot of the issue concerning stability and such on the 447 thread.

The more we saw of the AB330, and the FDR traces, the more it was apparent that the thing was and is a good design. So smooth an entry to the stall that the crew did not understand why the sucker wasn't reponding to stick commands.

Many of the bent wing designs have obvious clues when you are gettiing to high AoA. Buffet, wing rock, maybe aileron reversal and so forth. Others are smooth and stick shakers or pushers can save the day.

The AB330 does not appear to be statically neutral from what we saw, but the control laws make it appear so. If you use a gee command for pitch, then you will not have speed stability WRT AoA or Q. Duhhhh? Then I see the 737 with the STS kludge and I cannot find enuf early 737 data to indicate a need for the STS when the dinosaur model was certified.

One and not the only reason that a good FBW implementtion helps the $$$, is you can fly with less trim drag by using the stab to keep the tail up than forcing the nose down. My trusty Viper was and is the classic case. However, I do not think that Airbus developed the 320 and subsequent FBW models to be inherently speed neutral or have much longitudinal stability issues. Sure, you could get away with some aft cee gee, but could always fly the plane as you would any other. I"m not even sure if the USAF F-22 and F-35 have the same longitudinal stability properties as the F-16. Their demo routines show stuff that we Viper drivers couldn't dream of, primarily the really high AoA stuff.

Gums sends...

[Sublogic]

Amazing thread. I always believed that the 737NG was a redesigns similar to the 747-400 - shocking to here it is still FBC.
I saw that reference was made to the AF447 crash - truly shocking. And very helpfull. The AF crash makes very clear that problematic pilot skills are not at all related to the mother country of the airline in question. And that makes the discussion about possible pilot shortcomings in relation to the 737Maxs crash bearable, because one thing is clear: Nothing becomes worse than errors made during the AF crash, and this was a true European airline’s crash.
(Same goes for AirEgypt 990 and Germanwings 9525)

Written by a surprised Pax.

[737 Driver]

Simple.

Remove the flaw. Either remove the aerodynamic stability problem or make the FBW fix a proper one (like an Airbus, triple inputs, 14 computers, multiple layers of automatic or selectable degraded flight modes).

Train the pilots. If a single failure (here AoA) causes a monster, then prepare the pilots by training.

As someone who has moved back and forth, twice, between the 737 and A320, I can't begin to describe how lowly I view the Renton tractor. Boeing made a flawed aircraft and failed to mandate sufficient training. The pilots are as much victims as the passengers. No doubt at all.

There will never be a flawless aircraft or flawless maintenance or flawless training or flawless pilots. But at the end of the day, it is the pilots and their passengers who will be on the receiving end of these inevitable flaws. Thus our focus and our determination to overcome those flaws ought to be greater.

Throughout the history of aviation, pilots have been handed unique malfunctions or adverse situations for which there was no prior history, no procedure, no checklist. Many of these situations were also initially confusing, mentally taxing, and potentially paralyzing. Some crews performed, if not flawlessly, at least well enough to stabilize the situation and get the aircraft safely back to earth. Some crews did not.

In a remarkable number of these events, the difference between success and failure came down to the exact same answer - the crew's ability to overcome the startle effect, look past the distractions, and focus on the basics of flying the aircraft. Turn off the automation, set the proper attitude, set the power, trim out the control forces, monitor the performance, move the aircraft away from the threat. The pilots don't have to be perfect or diagnose the problem right away. Fly the aircraft and buy some time. Very, very few of our non-normals need to be executed so fast that we can't first devote the majority of our attention and the necessary time to flying the aircraft.

Training is key, but it has to be the right kind of training. Training scripts in the simulator where you pretty much know not only the problem but the answer ahead of time do little to prepare a pilot for the visceral challenges of the unexpected. Overemphasis on automation to the point that even seasoned pilots feel that tad bit of discomfort when the autopilot and autothrottles click off is a definite warning sign. When all goes to hell, do you have a good idea - right now - where the aircraft pitch and power and airspeed should be for takeoff? low altitude? high altitude? missed approach? Do you know your memory items and limitations cold? If not, you have some homework to do.

It is too late to save the crew and passengers of these two accident, but it is not too late to learn from them. Some commercial pilots have stated here that they could not have done any better, and I'm here to say that is a cop out. If you are a commercial pilot and feel that you cannot - under the duress of distracting warnings and information - turn off the automation, set a reasonable pitch and power setting, establish a climb, hold a heading, and trim the controls as necessary, then you need to do something about that right now.

[Lost in Saigon]

When I was trained on the 737 (classic and NG), the stab trim runaway was a runaway - where the trim wheel ran continuously. We would identify it as a runaway, because it was continuously running, and flick the switches.

1. MCAS activation is not continuous, it's bursts.
2. The 737 trim system likes to provide bursts of random trim at certain times (STS) so bursts are considered normal.

This is why the Boeing excuse "they should have done the runaway stab QRH to fix the MCAS problem" is a load of utter nonsense. 737 Driver - pinning this on lack of airmanship will costs lives in the future.

Back in November 2018 Boeing issued a bulletin about the MCAS Stab Trim problem and many airlines responded by removing the word “CONTINUOUS” from the Runaway Stabilizer checklist.


https://oi2.photobucket.com/albums/y17/msowsun/0A97160E-9F31-4DCF-8F08-974B842551E2.jpeg

[Bend alot]

Back in November 2018 Boeing issued a bulletin about the MCAS Stab Trim problem and many airlines responded by removing “continuous” from the Runaway Stabilizer checklist.


What exactly was the MCAS Stab Trim problem?

[HundredPercentPlease]

..., and I'm here to say that is a cop out. If you are a commercial pilot and feel that you cannot - under the duress of distracting warnings and information - turn off the automation, set a reasonable pitch and power setting, establish a climb, hold a heading, and trim the controls as necessary, then you need to do something about that right now.

Of course everyone here can do that. The ET crew could do that. Do you really think that an 8000 hour 737 captain didn't know how to do that?

You are missing the point - which is why they didn't do that. Or maybe why they couldn't do that. Or most importantly, why you may not do that as some point in the future.

[Lost in Saigon]

What exactly was the MCAS Stab Trim problem?

The “problem” was explained in the Boeing Bulletin issued back in November 2018 after the Lion Air accident.

“Uncommanded nose down stabilizer trim due to erroneous Angle of Attack during Manual flight only”

https://www.pprune.org/10447071-post3969.html

[737 Driver]

Of course everyone here can do that. The ET crew could do that. Do you really think that an 8000 hour 737 captain didn't know how to do that?

There is no practical difference between a pilot who does not have certain skills and a pilot who cannot demonstrate those skills when needed.

You are missing the point - which is why they didn't do that. Or maybe why they couldn't do that. Or most importantly, why you may not do that as some point in the future.

Actually, this is exactly my point. I'm sure on nice sunny day with no distractions, or maybe with a jumpseater who could provide a third set of eyes, or perhaps during a pre-briefed sim session when they knew the malfunction was coming, either the Captain or First Officer could have parked the pitch at 10 degrees, set the power to 80% N1, trimmed the stab up to neutral no matter what spurious inputs the automation was making, and flown safely away from the ground. Unfortunately, in the real world we do not always have the luxury of being free from distractions, or having that jumpseater, or having our emergencies pre-briefed.

Why indeed could these crews not perform to the standards expected of a commercial pilot? Perhaps automation dependency and lack of hand-flying experience? Maybe an airline and training culture that emphasized rote procedures or systems management over basic airmanship skills? Sim training that was long on following scripts and checklists and short on big picture flying? First Officers that were light on experience and/or discouraged from speaking up when necessary? Perhaps some personal issues with the specific individuals? I could go on, but this would be a good start. I suspect the various accident boards will be looking at all these issues.

Yes, they could have and they should have but they didn't. That is why the human factor element of these accidents cannot and should not be ignored.

[MurphyWasRight]

The “problem” was explained in the Boeing Bulletin issued back in November 2018 after the Lion Air accident.

“Uncommanded nose down stabilizer trim due to erroneous Angle of Attack during Manual flight only”

https://www.pprune.org/10447071-post3969.html

It is interesting that the revised runaway trim card in the official emergency AD is significantly different from the one in above, the note about using manual electrical trim was moved to the bottom and is not directly below the 'action' items. See page 7:

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf/0/fe8237743be9b8968625835b004fc051/$FILE/2018-23-51.pdf

Would a pilot converting to MAX in November have seen the Boing bulletin or just the revised per emergency AD manual?
Are the bulletins typically discarded when an official AD is issued?

Both of them talk of 'higher control forces may be needed' they do not specifically state that the manual trim might be unusable in a significantly mistrimed state.
Would be easy to read that as referring to column forces, especially by a someone not trained in the 'unloading'/ roller coaster maneuver

[Bend alot]

It is interesting that the revised runaway trim card in the official emergency AD is significantly different from the one in above, the note about using manual electrical trim was moved to the bottom and is not directly below the 'action' items. See page 7:

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf/0/fe8237743be9b8968625835b004fc051/$FILE/2018-23-51.pdf

Would a pilot converting to MAX in November have seen the Boing bulletin or just the revised per emergency AD manual?
Are the bulletins typically discarded when an official AD is issued?

Also with the inclusion of "up to 10 seconds" clearly directed at MCAS - by MCAS not reference in either document.

Seems like a cover up - a non cover up would have given pilots more tools, like a L/H AoA failure can cause...............

[737 Driver]

Both of them talk of 'higher control forces may be needed' they do not specifically state that the manual trim might be unusable in a significantly mistrimed state.


I don't know for sure, but I think this statement might be a reference to activation of the Elevator Feel Shift Module (EFSM). This module is one of the 737 systems that may be activated by a stall signal from the Stall Management Yaw Damper (SMYD) computer. Activation is accompanied by annunciation of the FEEL DIFF PRESS light which is one of the symptoms mentioned in the AD.

Relevant quote from the 737 Aircraft Maintenance Manual (AMM)

EFSM Operation

At stall onset, either SMYD sends a signal to energize the dual coil solenoid valve on the EFSM. The EFSM operation occurs when all of these conditions occur:
• Stick shaker is active
• AOA is 8 to 11 degrees more than thermal anti-ice (TAI) biased stick shaker AOA
• EFSM is not inhibited due to low altitude or the airplane is on the ground.

When all of these conditions occur, the SMYDs energize the dual coil solenoid valve. The solenoid valve sends 3000 psi system A pressure to the pressure-operated mode valve. The mode valve opens and sends pressure between 820 psi to 880 psi from the pressure reducer to the system A side of the dual feel actuator. This increases the control column feel forces up to four times nominal feel. The increased feel force makes sure the pilots cannot easily override automatic stabilizer movement to nose down pitch of the airplane.

The FCOM has similar (though less detailed) information, though oddly it states the control forces only double.

[Loose rivets]

I've tried to look into the minds of the pilots in the latter part of this thread. I've even suggested that the ET PF's prior knowledge may have been counterproductive. The realisation that he is experiencing the same set of issues that were disastrous only months ago may have been truly alarming, countering any advantage he could have gained by having prior knowledge.

Suppose he was fixating on the attitude - he knows it's what he's supposed to do in this scenario. But he's also learned the autopilot could take the technical problem away and so frantically stabs at that a few times. Remember, things are very, very unreal to him at this time. Someone retorted that he didn't remember the flaps shouldn't be raised. Fair comment, but only recalling part of a briefing is not surprising at this moment.

So what's happening if he was focussing on the attitude? One thing's reasonably certain - he will* experience some tunnel vision. Not optical, but a kind of narrowed visual processing. Could it conceivably be enough to stop him seeing the wheel's white flashes? It seems impossible but how else is that protracted period of automatic spining explained? Is it the STS working harder, since the power is still high? I doubt he was that analytical with his hands full and being deluged with bad news.

*Being human is having more sub-processing going on that in the Boeing. We've all seen the spinning radar head change direction, despite knowing it hasn't. Or the Necker wire frame cube. We know that a sudden change happens, but what is incredible is that in most humans, it happens after a given number of seconds. That is very serious interference with our concious processing. Just an amusing bit of psychology, until you realise just how susceptible we are to our minds doing their own thing. A lot goes on that we can not escape from. Training around illusionary effects of acceleration and the products of fear is all we can do, and that's easier said than done.
.
.
.

[Zeffy]

https://www.flightglobal.com/news/articles/us-pilots-test-boeings-new-computer-based-max-train-457736/


US pilots test Boeing’s new computer-based Max training


26 APRIL, 2019 SOURCE: FLIGHT DASHBOARD BY: JON HEMMERDINGER BOSTON

Boeing is sharing a proposed computer-based pilot training session with US pilot unions as part of its work to return the 737 Max to service, several sources familiar with Max’s re-certification efforts say.

The computer-based training session reviews the 737 Max’s speed trim system and the manoeuvring characteristics augmentation system (MCAS), which has been identified as among factors contributing to two 737 Max crashes.

Boeing has said it is developing new training, as well as updating the MCAS software, but the Chicago-based company has released few details.

Sources, who decline to be identified, now say Boeing has been sharing the computer training with pilots from unions representing cockpit crew at major US airlines.

The sources indicate that the airframer seeks to solicit feedback and objective input from pilots, and to ensure the aviation community’s involvement in efforts to return the Max to service.

Boeing’s proposed computer-based training can be completed on laptop or tablet computer, and takes as little as 15min, sources say.

The new speed trim training course comes in addition to existing computer training for pilots transitioning from the 737NG to the 737 Max. That existing course can be completed in less than 1h, according to one pilot.

Boeing did not immediately respond to a request for comment.

Some US pilots say 15min is enough to understand the speed trim system, noting their familiarity with the 737 Max. Other pilots have, more broadly, expressed frustration for receiving what they describe as minimal training when transitioning from the 737NG to 737 Max.

Three US airlines operated the 737 Max prior to the Federal Aviation Administration’s 13 March grounding: American Airlines, Southwest Airlines and United Airlines.

The three unions representing those company’s pilots decline to comment. The unions include the Southwest Airlines Pilots Association, the Allied Pilots Association, which represents American’s pilots, and the Air Line Pilots Association, which represents United’s cockpit crew.

The FAA will need to sign off on Boeing’s training and its software update, prior to lifting the 737 Max grounding, sources note.

What is still unclear is whether regulators might require training in addition to the computer-based sessions, such as time in a flight simulator.

However, on 25 April, Southwest Airlines chief executive Gary Kelly cast doubt on the possibility of additional simulator training. “We are not hearing that will be a requirement," he said. “Managing the aircraft in a runaway stabiliser scenario is something that we've already covered.”

The day before, Boeing chief executive Dennis Muilenburg said the company had completed 135 test flights with the MCAS update, equating to more than 230h of flight-test time. The airframer has said it completed flight tests of the software update on 17 April.

Last week, an FAA panel released updated pilot training standards that now call for pilots to receive ground training that addresses MCAS “system description, functionality, associated failure conditions and flight crew alerting”.

“These items must be included in initial, upgrade, transition, differences and recurrent training,” the updated report said.

Boeing introduced the speed trim system on the 737NG, then added MCAS to the Max. MCAS ensures the types operate similarly by pushing the Max’s nose down if the system senses it is too high.

MCAS activated prior to the October 2018 crash of a Lion Air 737 Max 8 and the March crash of an Ethiopian Airlines aircraft of the same type. It apparently activated following input of faulty angle-of-attack data, investigators have said.

Boeing’s Muilenburg has taken responsibility for updating MCAS, though the crashes have spurred discussion about pilot training and questions about what role pilots may have played in the crashes.

Both investigations are ongoing.

[Winemaker]

Pretty interesting video about pilot decision making.

https://youtu.be/BBpqvPujZgM

[Water pilot]

Boeing’s proposed computer-based training can be completed on laptop or tablet computer, and takes as little as 15min, sources say

Well that sounds like thorough and comprehensive training to me! Seriously, four hundred people died, it was the pilot's fault entirely, and this is their solution?

[GordonR_Cape]

Pretty interesting video about pilot decision making.

Interesting indeed. Covered in a thread on this forum last year: https://www.pprune.org/accidents-close-calls/609093-miss-velma-s-engine-failure-crash-landing-duxford-cockpit.html

[Bend alot]

Well that sounds like thorough and comprehensive training to me! Seriously, four hundred people died, it was the pilot's fault entirely, and this is their solution?

Water pilot, you do understand it is in addition to the differences training that can be done in under an hour on the iPad!

I hope the rest of the world regulators fight for correct training levels - what ever that maybe, but I doubt 15 mins cuts it!

[FrequentSLF]

Well that sounds like thorough and comprehensive training to me! Seriously, four hundred people died, it was the pilot's fault entirely, and this is their solution?
15 minutes training? No offense to all the professionals on this forum, but I will not get close to any MAX, an unstable airframe will be fixed by a software patch, and such will require 15 min training? When certifications were written there was bot software patch, airframes havd to complay by DESIGN

[formulaben]

Well that sounds like thorough and comprehensive training to me! Seriously, four hundred people died, it was the pilot's fault entirely, and this is their solution?

How many hours/days/weeks/years of training do you suggest is appropriate to reinforce/retrain that one needs to use normal trim to re-trim to an appropriate speed and then use the pitch trim disconnect switches in the event of an MCAS or runaway trim event?

[Water pilot]

Objectively, seven pilots from various countries failed to recognize the "obvious" fact that they had runaway trim. A whole bunch of people died as a result. If this is a training issue, I want however much training is required to correct this deficiency.

[Bend alot]

How many hours/days/weeks/years of training do you suggest is appropriate to reinforce/retrain that one needs to use normal trim to re-trim to an appropriate speed and then use the pitch trim disconnect switches in the event of an MCAS or runaway trim event?

When you kill that MCAS or it has it's once limited "correction" - you are flying an aircraft that can no longer meet the certification requirements that it is approved for!

So say again - it no longer can meet certification requirements in certain flight modes/areas.

So how often do you fly outside certification limits? and how much training did you receive to do that? and was it on an Ipad?

This is not retaining - you have never flown in un-certifiable condition before on a 737 where MACS is required but not available.

Note this has nothing to do with a MCAS run away or trim run away - this is in normal flight when MCAS has been shut down (a number of events can now do this) or had one input and can not now, put in a second input to keep in certification limits..

[formulaben]

When you kill that MCAS or it has it's once limited "correction" - you are flying an aircraft that can no longer meet the certification requirements that it is approved for!

So say again - it no longer can meet certification requirements in certain flight modes/areas.

So how often do you fly outside certification limits? and how much training did you receive to do that? and was it on an Ipad?

This is not retaining - you have never flown in un-certifiable condition before on a 737 where MACS is required but not available.

Note this has nothing to do with a MCAS run away or trim run away - this is in normal flight when MCAS has been shut down (a number of events can now do this) or had one input and can not now, put in a second input to keep in certification limits..

Sorry, I can't interpret your answer. Perhaps you must have misinterpreted my question, so I'll ask it again and this time I'll go slowly and use different words: you seem upset with the re-training procedure; so I will ask again what quantity of training do you suggest is appropriate to reinforce/retrain that one needs to use normal trim to re-trim to an appropriate speed and then use the pitch trim disconnect switches in the event of an MCAS or runaway trim event? What amount of training is appropriate for any other event?

[Bend alot]

Sorry, I can't interpret your answer. Perhaps you must have misinterpreted my question, so I'll ask it again and this time I'll go slowly and use different words: you seem upset with the re-training procedure; so I will ask again what quantity of training do you suggest is appropriate to reinforce/retrain that one needs to use normal trim to re-trim to an appropriate speed and then use the pitch trim disconnect switches in the event of an MCAS or runaway trim event? What amount of training is appropriate for any other event?

You do understand MCAS is a requirement for flight within certification requirements?

With MCAS disabled (due now to any of a number of reasons) - how is flight within certification requirement limits meet?

Nothing at all to do with any trim event (Important you understand that) but what is flight like outside the certifiable limits?

I will agree there is NO REQUIREMENT for a trim run away - extra training, it is pointless



I do believe that training is required if the aircraft has probable possibility to be flown outside certification limits, but within the approved flight envelope of the aircraft.

Training required is not known by most of us, but only those that have flow MCAS during it's testing. It is reasonable to believe that the difference with MCAS and without MCAS is pretty large, as design used 0.6 degrees as the input but in flight tests 2.5 was required to get the correct feel.

[wonkazoo]

Just getting caught up after a long day of family stuff.

First I want to thank the individuals who had kind words, or otherwise expressed positive thoughts about my post from last night. After putting it out there I was torn, worried that I had made a mistake- I now see I did not.

Second- 737 Driver and others bring up really valid points and if/where we see things differently it isn't in the idea that the system failed completely. I would argue that putting a kid with less than 300 hours in the right seat of any transport category aircraft is near malpractice, and should said aircraft hit the ground in an uncontrolled dive blaming that kid is not only unfair, it is downright obscene. When I shared what I did last night it wasn't to expiate the guilt of the crews, but instead to try and get people to realize that "blaming" people who are no longer here to defend themselves is a bit disingenuous, and equally it distracts us from the very real root causes of the two incidents.

There is one huge difference between my position and that expressed most recently by 737 Driver, and that is to the responsibility for the outcome of what happened. Note that I say responsibility and not blame. After reviewing the technical and other data in great detail I am confident that responsibility lies solely with one party, as aided and abetted by another. Once the dominoes had been lined up the outcome was basically assured as it was only a matter of time.

Specifically: Boeing designed and placed into service an airplane with an active control system that had unilateral control over the horizontal stabilizer, with enough authority to place the airplane in an unrecoverable state if just a single component failed. Further this system gave no indication to the pilots that it was operating, or when malfunctioning that it was operating in error. Additionally this system, which was created solely to increase the amount of force required to pitch up the aircraft at high AOA used the most critical part of the airframe to do this minimal task, instead of using a passive system that had no control authority.

The result of this sad effort was a system that, if it failed, would basically try to kill the pilot and everyone on board. I say again: MCAS will try to kill everyone on board if it fails.

I simply cannot recall (but am inviting others here to fill in the blanks if you can) another system on a transport category aircraft with a failure mode that defaulted to "I'm going to try to fly the airplane into the ground. If you line up all the dots and pull two switches at the right moment I will let you live. Otherwise you die... Oh, and BTW I'm also going to fail concurrently with three or four other systems, which actually will alert you to their issues, unlike me, who will sit here quietly winding your trim forward until you get to the point where you cannot wind it back. Sorry about that!!" (It's also worth noting here that the Emergency AD that was put out only gave instruction on what was essentially an enhanced trim runaway. There is no actual way (that I have seen) for a pilot to actually determine if MCAS is malfunctioning. At best you are to stop the resultant (trim runaway) and remain in ignorance over the state of MCAS. WTF?? A system with complete authority over the horizontal stab and you have no way of knowing anything about it. Failure modes, operational status, errors, nothing. Just "If the airplane is trimming down (for whatever reason) and you don't want it to pull the console switches." Really??)

These incidents, indeed the entirety of MCAS' existence are a failure of corporate responsibility aided and abetted by a complete abrogation of regulatory responsibility. All in the pursuit of profits for shareholders.

We can blame the previous Lion Air Crew and maintenance for a lot. We can find fault with the performance of the crews, and we will. But in the end, the only entity who both could have designed a safe airplane, and who not only failed but by all appearances worked to conceal their failure through omission, was Boeing. And the agency that looked the other way was the FAA.

Those are the responsible parties, and that is what I hope people will look carefully at. It starts with the airplane. Build a safe one and operators will still find a way to muck things up, and crews will still make mistakes. But step one, the most important step, is build an effing safe airplane.

Warm regards,
dce

[GordonR_Cape]

When you kill that MCAS or it has it's once limited "correction" - you are flying an aircraft that can no longer meet the certification requirements that it is approved for!

So say again - it no longer can meet certification requirements in certain flight modes/areas.

So how often do you fly outside certification limits? and how much training did you receive to do that? and was it on an Ipad?

This is not retaining - you have never flown in un-certifiable condition before on a 737 where MACS is required but not available.

Note this has nothing to do with a MCAS run away or trim run away - this is in normal flight when MCAS has been shut down (a number of events can now do this) or had one input and can not now, put in a second input to keep in certification limits..

I agree with most of your concerns, and have made similar comments myself. The revised MCAS details are still not clear, but there are two "escape" causes that could bypass your argument:
- The first is that MCAS may not be imited to one activation per flight, but can do so again, if a specific set of conditions permit. For example, nose-down trim unwinding, or AOA remaining below the threshold, together with no pilot control inputs for 15 continuous seconds.
- The second is that AOA disagree could be treated as a MEL equipment failure, and mandate landing at the nearest avaliable airport. I have not seen any reference to this, so the implication may be that MCAS is not flight critical, but rather a paper certification issue for a rarely encountered flight condition.

Whether the Joint Authorities Technical Review buy either of these arguments remains to be seen.

Edit: My comment was drafted while other replies to the same point were posted.

[Bend alot]

I agree with most of your concerns, and have made similar comments myself. The revised MCAS details are still not clear, but there are two "escape" causes that could bypass your argument:
- The first is that MCAS may not be imited to one activation per flight, but can do so again, if a specific set of conditions permit. For example, nose-down trim unwinding, or AOA remaining below the threshold, together with no pilot control inputs for 15 continuous seconds.
- The second is that AOA disagree could be treated as a MEL equipment failure, and mandate landing at the nearest avaliable airport. I have not seen any reference to this, so the implication may be that MCAS is not flight critical, but rather a paper certification issue for a rarely encountered flight condition.

Whether the Joint Authorities Technical Review buy either of these arguments remains to be seen.

Edit: My comment was drafted while other replies to the same point were posted.

Yes details are low!

The fact you actually understand MCAS conditions are not limited to a "run away trim" and actually MCAS is required to meet certification requirements during manual flight and this may require training (hands on), is good to know - seems many do not understand.

[edmundronald]

Rumors concerning whistleblower reports about the AoA sensor are emerging.

"One whistleblower reported to the FAA that they had seen damage to the electrical wiring connected to the plane’s angle of attack sensor from a foreign object, which feeds data to the MCAS system so it can determine whether it needs to engage to prevent the plane from stalling. "

https://interestingengineering.com/boeing-whistleblowers-report-more-737-max-8-problems-to-faa
Edmund

[threemiles]

Rumors concerning whistleblower reports about the AoA sensor are emerging.

"One whistleblower reported to the FAA that they had seen damage to the electrical wiring connected to the plane’s angle of attack sensor from a foreign object, which feeds data to the MCAS system so it can determine whether it needs to engage to prevent the plane from stalling. "

https://interestingengineering.com/boeing-whistleblowers-report-more-737-max-8-problems-to-faa
Edmund

A single sensor failure of any kind on any airliner happens every day and is a no-brainer. Except on the MAX, thanks to Boeing and FAA.

We can blame the previous Lion Air Crew and maintenance for a lot. We can find fault with the performance of the crews, and we will. But in the end, the only entity who both could have designed a safe airplane, and who not only failed but by all appearances worked to conceal their failure through omission, was Boeing. And the agency that looked the other way was the FAA.

Those are the responsible parties, and that is what I hope people will look carefully at. It starts with the airplane. Build a safe one and operators will still find a way to muck things up, and crews will still make mistakes. But step one, the most important step, is build an effing safe airplane.

Thanks. Can't say it better.

[Icarus2001]

When you kill that MCAS or it has it's once limited "correction" - you are flying an aircraft that can no longer meet the certification requirements that it is approved for!

So say again - it no longer can meet certification requirements in certain flight modes/areas. This is true but only in one very specific flight regime at very high angles of attack, near the critical angle, which during a lifetime of line flying a crew is unlikely to ever get near.

You try make it sound like the aircraft is uncontrollable if the trim disconnects are selected off and MCAS is isolated. Nothing could be further from the truth.

So how often do you fly outside certification limits? and how much training did you receive to do that? and was it on an Ipad?
With the trim disconnects off you will not be flying outside of limits, only at VERY high AoA and WTF are you doing flying there?

If I remove the interior rear vision mirror from my car it is no longer equipped "as certified" by Australian Design Rules (ADR) and would not be roadworthy, technically. Is it still safe to drive, of course it is.

[formulaben]

You do understand MCAS is a requirement for flight within certification requirements?

With MCAS disabled (due now to any of a number of reasons) - how is flight within certification requirement limits meet?

Nothing at all to do with any trim event (Important you understand that) but what is flight like outside the certifiable limits?

I will agree there is NO REQUIREMENT for a trim run away - extra training, it is pointless



I do believe that training is required if the aircraft has probable possibility to be flown outside certification limits, but within the approved flight envelope of the aircraft.

Training required is not known by most of us, but only those that have flow MCAS during it's testing. It is reasonable to believe that the difference with MCAS and without MCAS is pretty large, as design used 0.6 degrees as the input but in flight tests 2.5 was required to get the correct feel.

MCAS is NOT required for certification. It is the feedback that is required.

Yet AGAIN, I ask you (perhaps pointlessly, and for the 3rd effing time) since you seem to be unsatisfied with the training program, I say again, how much training do you suggest is appropriate to reinforce/retrain that a professional pilot needs to use normal trim to re-trim to an appropriate speed and then use the pitch trim disconnect switches in the event of an MCAS or runaway trim event? What amount of training is appropriate for any other event?

I am actually asking for a quantitative number, not rhetoric, as your last answers suggest.

[Bend alot]

MCAS is NOT required for certification. It is the feedback that is required.

Yet AGAIN, I ask you (perhaps pointlessly, and for the 3rd effing time) since you seem to be unsatisfied with the training program, I say again, how much training do you suggest is appropriate to reinforce/retrain that a professional pilot needs to use normal trim to re-trim to an appropriate speed and then use the pitch trim disconnect switches in the event of an MCAS or runaway trim event? What amount of training is appropriate for any other event?

I am actually asking for a quantitative number, not rhetoric, as your last answers suggest.

The area of training in the mentioned area of WTF are you doing here/ how am I here - as mentioned in Icarus 2001's post

You do seem rude and yes I am unsatisfied with the training program - I think everyone is/was unsatisfied with the original and hidden release of MCAS (not even mentioned) training - even now Boeing! so why just agree with Boeing's new training - we do not even know what it is other than a very short iPad or PC event, or do you have details?

I want to know how the aircraft feels both with and without MCAS and do not think that is possible on a PC or iPad session.

Please be professional and polite in your reply.

My reply is FAR more training, and with training that contains the elements effected - "FEEL"

[formulaben]

Please be professional and polite in your reply.

I am not rude and I asked 3 times...thank you for finally answering that you have no clue how much more training is required.

[coaldemon]

At the end of this it doesn't matter what you all think the training should be or will be. Each Airline has to do an assessment and think about what their crew needs are. I know a couple of major Airlines that haven't done a Runaway Stab event in years so I would say they may revisit that.

Certainly at the end it will be public opinion that determines a lot of this. Good luck to the CEO of any airline operating MAX's that says we only did the CBT as that is all the FAA said to do. The Twitter feedback will be huge...

[nyt]

Boeing cut cost by patching big engines on an old airframe design, requiring MCAS to be certified. Boeing crippled (let me know if you find a better word) MCAS to limit training / certification costs. There's only so much you can do to cut costs before bad things happen, and it looks like they still don't get it by not going back to the drawing board and think that "fixing" MCAS is enough. At the very least, they redesign MCAS properly with all the necessary training, and if it means a new type rating, so be it. Time will tell !

[Bend alot]

I am not rude and I asked 3 times...thank you for finally answering that you have no clue how much more training is required.

Correct as there is no public information on exactly MCAS is required to keep the MAX within certification limits.

All we do know is that MCAS was the option Boeing decided to use to get the MAX certified - now "the fix" servery decreases the MCAS to be active. So the question is how can it still operate in the certification limits?

After that what training (or other limits) are required. ???

It seems possible to remove MCAS requirement by a minimum weight limit and/or a AFT C of G limit - but they have never been mentioned as part of the "fix".

[73qanda]

This whole 737 Max debacle is a result of the executive management MO industry wide, Manufacturers, Airlines, Maintenance Organisations, Regulators, Training Organisations.......They are all run by people who gain financially when costs are cut, and who don’t really understand the risks they are charged with mitigating.
It’ll be addressed one day but only when jets are falling out of the sky at twice the rate they are now.

[bill fly]

Rumors concerning whistleblower reports about the AoA sensor are emerging.

"One whistleblower reported to the FAA that they had seen damage to the electrical wiring connected to the plane’s angle of attack sensor from a foreign object, which feeds data to the MCAS system so it can determine whether it needs to engage to prevent the plane from stalling. "

https://interestingengineering.com/boeing-whistleblowers-report-more-737-max-8-problems-to-faa
Edmund

So as mentioned by a couple of us many pages back, why not do a quality control check on the hundreds of grounded Max aeroplanes to see how widespread, if at all FOD or wiring damage might be?

[bill fly]

Specifically: Boeing designed and placed into service an airplane with an active control system that had unilateral control over the horizontal stabilizer, with enough authority to place the airplane in an unrecoverable state if just a single component failed. Further this system gave no indication to the pilots that it was operating, or when malfunctioning that it was operating in error. Additionally this system, which was created solely to increase the amount of force required to pitch up the aircraft at high AOA used the most critical part of the airframe to do this minimal task, instead of using a passive system that had no control authority

Yep. So it is. And still they are faffing around with MCAS to get it recertified.
The only honest way out of this, and it isn’t cheap, is a dedicated feel augmentation within the control run. Can be a spring, or a feel unit mod, as suggested way back, but not yet more tampering with the stabiliser.
I never liked the STS on the 300 and since then B have made use of stab tinkering for other sorts of cases - tankers etc. When we did a max fuel transfer on the Victor, we had to keep both of the aircraft in trim - and we did this by trimming as required, without some background programme interfering.
I guess the most important phrase here is isn’t cheap.
These days that is enough reason for not doing the honest solution.

[Sucram]

Gums,

As I understand it, when designing the A320 Airbus toyed with the idea of reduced stability, citing FBW as the "excuse". The whole world raised a regulatory eyebrow and Airbus designed a fully stable aircraft.

Ironically, Boeing designed a less than stable aircraft with a bit of bolt on, undocumented FBW, and the world continued to rotate, until two crashed.
The 737 is an old generation aircraft with old generation failings, the A320 is not.
Most of the mods carried out on the 737 since it was introduced were to increase its profitability not safety. In fact it could be argued that some of the mods have even reduced its safety. Im sure Boeing are now wishing theyd developed a completely new aircraft instead.

[GordonR_Cape]

Specifically: Boeing designed and placed into service an airplane with an active control system that had unilateral control over the horizontal stabilizer, with enough authority to place the airplane in an unrecoverable state if just a single component failed. Further this system gave no indication to the pilots that it was operating, or when malfunctioning that it was operating in error. Additionally this system, which was created solely to increase the amount of force required to pitch up the aircraft at high AOA used the most critical part of the airframe to do this minimal task, instead of using a passive system that had no control authority

Yep. So it is. And still they are faffing around with MCAS to get it recertified.
The only honest way out of this, and it isn’t cheap, is a dedicated feel augmentation within the control run. Can be a spring, or a feel unit mod, as suggested way back, but not yet more tampering with the stabiliser.
I never liked the STS on the 300 and since then B have made use of stab tinkering for other sorts of cases - tankers etc. When we did a max fuel transfer on the Victor, we had to keep both of the aircraft in trim - and we did this by trimming as required, without some background programme interfering.
I guess the most important phrase here is isn’t cheap.
These days that is enough reason for not doing the honest solution.

A feel augmentation system that takes AOA as input, what could possibly go wrong? I'm sure others can give scenarios where this would be a bad idea...

I previously pointed out that any system that takes a small input such as AOA, and produces a large output (whether feel or trim), is inherently undesirable and unpredictable. MCAS creates a semblance of smoothness by applying trim over a 10 second interval. Applying such a delay into elevator feel would create all kinds of feedback lags, and the solution could be worse than the problem.

The cost issue with any non-software change is how many years that would take to design, test and certify, and what production would be done in the meantime? Boeing have painted themselves into a corner, and the only way out seems to be double or quits (to mix metaphors).

[HarryMann]

I'm an engineer and a pilot. The responsibility is with Boeing/FAA, no question. Yes the ET302 crew could have done a few things different. But they had 6 minutes. In a little box in the sky, where the wrong answer meant death, with alarms going off, and not just useful alarms but alarms telling them to do the opposite of what they needed.

You train pilots to trust in safety systems, trust in automation, follow the checklists, follow the SOPs. They do this every day successfully for years. Then you expect them to instantly drop this and distrust all the safety systems and automation, work out which one is faulty and what to do about it, while simultaneously hand flying an aircraft that's behaving like they have never experienced before in any of the hand flying they've done.

Boeing had plenty of time, in nice safe offices that weren't about to crash into the ground, to get this right.

Being an engineer too but not an airline pilot, I thoroughly concurr...
'Good' engineers really shouldn't abrogate their responsibilities nor discharge them to other professionals working in a much less benign environment

However, one does feel a strong sense of 'modern management' involvement, possibly even interference.

All the good wartime and post war management methodologies seem to have been thrown out the window since the 90s and this fundamentally US trend of ignoring rhe importance of 'Domain Knowledge' has long since corrupted the UK and I assume, elsewhere. I understand Japanese industry were taught good disciplines postwar and hopefully have resisted the worst trends of Managementitis coming I imagine, from US academia and unwisely encouraged by shareholder pressure.

Apologies for waxing philosophic.. .but I cannot divorce an innate sense of betrayal over the years from what I see through this MCAS lens, though MCAS is only a sympton.

[bill fly]

A feel augmentation system that takes AOA as input, what could possibly go wrong? I'm sure others can give scenarios where this would be a bad idea...

I previously pointed out that any system that takes a small input such as AOA, and produces a large output (whether feel or trim), is inherently undesirable and unpredictable. MCAS creates a semblance of smoothness by applying trim over a 10 second interval. Applying such a delay into elevator feel would create all kinds of feedback lags, and the solution could be worse than the problem.

The cost issue with any non-software change is how many years that would take to design, test and certify, and what production would be done in the meantime? Boeing have painted themselves into a corner, and the only way out seems to be double or quits (to mix metaphors).

Hi Gordon,
Although I didn’t mention AoA as an input in that post, if you need to know AoA in order to correct elevator feel, then clearly you have to measure it. Done properly (dual input and monitor) and maintained correctly it is a valid measurement as used for years on many aircraft.
You could also ask what could possibly go wrong with a pitot system. There are probably more examples of failure in that system and yet it is universally used.
At some point you have to trust something for your data, so make it as reliable as you can and maintain it well.
As for feedback lags and delays, a spring is a wonderful reliable input which can be linearly or dynamically calibrated, and is used in many control run applications. The ten second interval used by MCAS would not apply - as long as the condition remained, the spring would stay compressed. As the condition decreased, so would the spring force. Qed. There are other force generators available, based on hydraulics or pneumatics although a spring is simple and less reliant on other systems.
Main thing is to have the force generated within the control run rather than by potentially powerful MCAS stab. movement (which still needs AoA input).
B

[737 Driver]

You do understand MCAS is a requirement for flight within certification requirements?

With MCAS disabled (due now to any of a number of reasons) - how is flight within certification requirement limits meet?

Nothing at all to do with any trim event (Important you understand that) but what is flight like outside the certifiable limits?


Point of order.

There are are a whole lot of systems that can and have failed on numerous aircraft that technically put that aircraft out of its limits for certification. You would never depart with failed engines, failed hydraulic systems, failed tires, etc. However, they do and have failed, and we have procedures in place to deal with those failures.

To your specific question of how one could possibly fly the 737 with a known MCAS failure once they fix the runaway stab thingy....., well how about staying away from the edge of the envelope and not stalling the aircraft?

[Bend alot]

Point of order.

There are are a whole lot of systems that can and have failed on numerous aircraft that technically put that aircraft out of its limits for certification. You would never depart with failed engines, failed hydraulic systems, failed tires, etc. However, they do and have failed, and we have procedures in place to deal with those failures.

To your specific question of how one could possibly fly the 737 with a known MCAS failure once they fix the runaway stab thingy....., well how about staying away from the edge of the envelope an not stalling the aircraft?
Perfect answer!

Just no mention of it in the fix.

As you are vocal and seems a very competent 737 pilot (certainly seems that way by your posts)

Can you detail how the/you cockpit would have responded after take off of the ET flight with you as Captain and with the 2-300 hr FO - who's job was who's when and why ?

Not a trap question just very interested.

Starting from the first warning you get and when you would accept it as a warning or a failure.

Thanks for detailed answers in reply (others let him reply and answer - he is clearly a very competent pilot on type)

[GordonR_Cape]

Hi Gordon,
Although I didn’t mention AoA as an input in that post, if you need to know AoA in order to correct elevator feel, then clearly you have to measure it. Done properly (dual input and monitor) and maintained correctly it is a valid measurement as used for years on many aircraft.
You could also ask what could possibly go wrong with a pitot system. There are probably more examples of failure in that system and yet it is universally used.
At some point you have to trust something for your data, so make it as reliable as you can and maintain it well.
As for feedback lags and delays, a spring is a wonderful reliable input which can be linearly or dynamically calibrated, and is used in many control run applications. The ten second interval used by MCAS would not apply - as long as the condition remained, the spring would stay compressed. As the condition decreased, so would the spring force. Qed. There are other force generators available, based on hydraulics or pneumatics although a spring is simple and less reliant on other systems.
Main thing is to have the force generated within the control run rather than by potentially powerful MCAS stab. movement (which still needs AoA input).
B

I am not an expert on flight instrumentation, but everything I have read about AOA vanes on the B737 in this thread, indicates that it is not a particularly well suited input parameter for direct command of flight controls. Stick shaker yes, that's a warning system. Fighter jets, yes its necessary. FBW aircraft, yes if validated against other parameters. The proposed Boeing fixes to MCAS, imply that none of this is true on the B737. AOA disagree tolerance of up to 5.5 degrees, what kind of input is that into a critical flight system in a passenger aircraft?

An analogy which I drafted in my comment (but then deleted), explains part of the situation: Imagine a motor vehicle driving down a potholed road, with all the irregularities transmitted to the steering wheel. Normally there is some kind of damper to prevent harsh feedback forces to the driver. Imagine that kind of instantaneous feel in the control column while trying to fly an aircraft?

Given the need for some kind of smoothing of AOA, by definition it would involve a delay or lag between pilot inputs and the feel forces. From a control systems theory viewpoint, delay lags are never a good thing, since they can lead to pilot induced oscillation, and other side-effects.

The opposite scenario, of full-force applied when over a threshold, is harsh and equivalent to a stick-pusher, with its own side-effects, training requirements, and type certification issues.

AFAIK MCAS was designed to avoid both scenarios, by being slow and unilateral. It fulfilled the criteria of not being harsh, nor could it induce short-period oscillations.

Sorry, if I took your comment and ran it to a logical absurdity, but IMO it would not be a simple fix. It really can be hard to explain complex control systems feedback, and I'm sure others can do it better,

[DaveReidUK]

I am not an expert on flight instrumentation, but everything I have read about AOA vanes on the B737 in this thread, indicates that it is not a particularly well suited input parameter for direct command of flight controls.

Historically, that has been an accepted strategy. A number of aircraft types in the past have been fitted with a stick-pusher, which uses AoA as an input and acts directly on primary pitch control (elevators).

However I'm not aware of any stick-pusher that acts on the input of a single sensor, with no redundancy.

Stick-Pusher Philosophy (https://www.flightglobal.com/FlightPDFArchive/1964/1964%20-%200246.PDF)

[737 Driver]

When I shared what I did last night it wasn't to expiate the guilt of the crews, but instead to try and get people to realize that "blaming" people who are no longer here to defend themselves is a bit disingenuous, and equally it distracts us from the very real root causes of the two incidents.

I suspect one of the reasons this is such a difficult topic is this concept of "blame." Watching some of the occasional "blame game" at my company, I've sometimes opined sardonically that it apparently wasn't really necessary to fix the problem as long as you could fix the blame. That is, as long as you could point to someone else's mistake, you didn't have to take personal responsibility to address the issue at hand. It is a natural human reaction, and it definitely plays out in the aftermath of these accidents.

There is one huge difference between my position and that expressed most recently by 737 Driver, and that is to the responsibility for the outcome of what happened. Note that I say responsibility and not blame.

I am more than happy to replace the word "blame" with "responsibility" (though I don't think I actually used the b-word in any of my posts). It certainly does not carry the same emotional connotation. But I will state again that my position, and I think pretty much the position of the entire aviation safety community, is that aviation accidents are rarely the result of a single cause. There are many links in the chain of causation. Yes, you can point to one link and say if this or that hadn't happened, then the accident would not have happened. However, if the goal is to make aviation safer, then you have to look at every link in the chain and address each problem on its own merits.

The result of this sad effort was a system that, if it failed, would basically try to kill the pilot and everyone on board. I say again: MCAS will try to kill everyone on board if it fails.

I would simply point out that there are a number of other system and components on every commercial aircraft flying today that fit this criteria. Engine failures, high altitude pressurization failures, smoke/fume/fire events would all be fatal if not for the timely intervention of the flight crew. The flawless aircraft simply does not exit. They will malfunction, and sometimes they malfunction in novel ways.

I simply cannot recall (but am inviting others here to fill in the blanks if you can) another system on a transport category aircraft with a failure mode that defaulted to "I'm going to try to fly the airplane into the ground.

Well, I could probably come up with a few more examples, but at my airline we had one aircraft land short of the threshold and rip off the gear when the autopilot went wonky on short final during a Cat II operation. I've personally experienced a sudden nose down departure on one of my previous aircraft during a practice autoland, though fortunately I was able to disengage the A/P and recover before anything nasty happened. I'm pretty sure that if an engine failed on takeoff and the pilots did not respond with the proper control inputs, the likely result would be a big smoking hole off the end of the runway. Once again, aircraft will malfunction, and it is incumbent on the pilots to be sufficiently vigilant (or maybe just constructively paranoid) to do whatever it takes to keep that aircraft flying.

These incidents, indeed the entirety of MCAS' existence are a failure of corporate responsibility aided and abetted by a complete abrogation of regulatory responsibility. All in the pursuit of profits for shareholders..........Those are the responsible parties, and that is what I hope people will look carefully at. It starts with the airplane. Build a safe one and operators will still find a way to muck things up, and crews will still make mistakes. But step one, the most important step, is build an effing safe airplane.

I'm not cutting Boeing, the FAA, or the airlines any slack for their role in these accidents. They all need to address their lapses. But as I've already stated, this is not a forum for Boeing. Or for the FAA. Or for airline managers.​​​​​​ We don't really have the power to address their issues. We do have the power to address ours.

This is a forum for professional pilots. Yes, we could sit back, point fingers, and opine about how badly someone else screwed up. Or we could take a hard look at our profession and ask why multiple crews had such difficulty and/or reluctance in applying some very basic airmanship techniques to resolve an aircraft malfunction that, while being unique and baffling, ultimately did not render the aircraft unflyable.

[DaveReidUK]

I simply cannot recall (but am inviting others here to fill in the blanks if you can) another system on a transport category aircraft with a failure mode that defaulted to "I'm going to try to fly the airplane into the ground.

TK1951 at AMS (also a 737) did pretty well that, albeit without all the extra bells, whistles and shakers.

Safety Recommendations from the investigation report:

Boeing should improve the reliability of the radio altimeter system.

The FAA and EASA should ensure that the undesirable response of the autothrottle and flight management computer caused by incorrect radio altimeter values is evaluated and that the autothrottle and flight management computer is improved in accordance with the design specifications.

[pilotmike]

Boeing designed and placed into service an airplane with an active control system that had unilateral control over the horizontal stabilizer, with enough authority to place the airplane in an unrecoverable state if just a single component failed. Further this system gave no indication to the pilots that it was operating, or when malfunctioning that it was operating in error. Additionally this system, which was created solely to increase the amount of force required to pitch up the aircraft at high AOA used the most critical part of the airframe to do this minimal task, instead of using a passive system that had no control authority.

The result of this sad effort was a system that, if it failed, would basically try to kill the pilot and everyone on board. I say again: MCAS will try to kill everyone on board if it fails.

I simply cannot recall... another system on a transport category aircraft with a failure mode that defaulted to "I'm going to try to fly the airplane into the ground. If you line up all the dots and pull two switches at the right moment I will let you live. Otherwise you die... Oh, and BTW I'm also going to fail concurrently with three or four other systems, which actually will alert you to their issues, unlike me, who will sit here quietly winding your trim forward until you get to the point where you cannot wind it back. Sorry about that!!" (It's also worth noting here that the Emergency AD that was put out only gave instruction on what was essentially an enhanced trim runaway. There is no actual way (that I have seen) for a pilot to actually determine if MCAS is malfunctioning. At best you are to stop the resultant (trim runaway) and remain in ignorance over the state of MCAS. WTF?? A system with complete authority over the horizontal stab and you have no way of knowing anything about it. Failure modes, operational status, errors, nothing. Just "If the airplane is trimming down (for whatever reason) and you don't want it to pull the console switches." Really??)

These incidents, indeed the entirety of MCAS' existence are a failure of corporate responsibility aided and abetted by a complete abrogation of regulatory responsibility.... {But} in the end, the only entity who both could have designed a safe airplane, and who not only failed but by all appearances worked to conceal their failure through omission, was Boeing. And the agency that looked the other way was the FAA.

Those are the responsible parties, and that is what I hope people will look carefully at. It starts with the airplane. Build a safe one and operators will still find a way to muck things up, and crews will still make mistakes. But step one, the most important step, is build an effing safe airplane.

Warm regards,
dce

This is probably the most concise, perceptive, and accurate summing up of this truly dreadful 737 MAX debacle. It really ought to be distributed widely to be seen by the widest audience possible.

It counters the apologists' excuses for Boeing's abominable design, and it should silence the criticisms of those who repeatedly try to blame the pilots of those 2 condemned flights / aircraft.

I am sad that it has taken so long for 'dce', 'wonkazoo' to come here to sum this up so perfectly, along with the important lessons for everyone from sharing such a vivid and honest account of their own '***** or bust' moment all those years ago. It takes a special mind to admit to failings with such openness and honesty, and we are all the richer for it. The question is, when will Boeing and the FAA similarly dig deep enough to find similar humility and honesty, and to redress the very clear failings?

Thank you, 'dce' - respect!

[737 Driver]

Can you detail how the/you cockpit would have responded after take off of the ET flight with you as Captain and with the 2-300 hr FO - who's job was who's when and why ?

Not a trap question just very interested.

Starting from the first warning you get and when you would accept it as a warning or a failure.


I suppose it wouldn't be fair to answer that I would never work at an airline where a 2-300 hour First Officer was a possibility. Far too many ways for that situation to go south.

In the case of Ethiopian, however, the answer is quite straightforward. After Lion Air, the existence and potential failure modes of MCAS were made public. This was a very hot topic around my airline as we operated the MAX. We have our own internal message board (not unlike PPRuNE), and different thoughts were kicked around. While there were some pilots who said they would refuse to fly the MAX until a more permanent fix was in place, the general consensus was that there were some basic techniques that could be used to mitigate the threat.

Since MCAS was inhibited by either the A/P or the flaps extended, the primary defense was to make sure you had one or the other. That is, on takeoff one would engage the A/P first and then retract the flaps. On landing, keep the A/P on until some amount of flaps were extended. If during takeoff, but before A/P engagement, you were to experience anything that looked like a failed AOA or unreliable airspeed, then don't retract the flaps. By applying these techniques, MCAS would never have an opportunity to activate. Whether these kind of discussions occurred at Ethiopian is currently unknown, but the information was available to process.

A better question would have been, "How would you have handled this malfunction as a Lion Air pilot who had no knowledge of MCAS?"

I think by now you may have gathered that I'm a hands-on type of pilot, so the answer is pretty much the same one I've been giving all along. Fly the aircraft.

By the numbers then: Stick shaker. WTF?! Check my power (increase as necessary), check my attitude, check my configuration. Is it flying or is it wallowing? If it is wallowing, keep the nose down and accelerate. If its flying, probably a false indication, continue the climb, call for the gear. Cross check instruments. I've got my hands full, so ask my FO to read off what he sees on all three airspeeds. At 400 feet check my roll mode, have FO ask for straight ahead if appropriate and declare emergency. If by now I've determined we have unreliable airspeed, memory items except I'm going to keep takeoff power and 15 degrees pitch until 1000' where I set 10 degrees and 80% N1.

Now I do absolutely nothing except climb to a safe altitude with flaps hanging. Once at a safe altitude, we proceed slowly and methodically through the NNC for Airspeed Unreliable. Quite frankly, I don't know if I would ever retract my flaps in this scenario (and hence no MCAS issue) because I'm going to return to the departure airport for landing.

If I ever did retract the flaps, it would only be after I had a stabilized aircraft. If MCAS then kicked in, I seriously doubt I would let the trim run continuously for 9 seconds before I did something about it. When you do a fair amount of hand-flying, trimming is like breathing. You hardly think about it. Controls get heavy, trim. Apply thrust, trim. Reduce thrust, trim. Enter a turn, trim. Rollout of turn, trim. If MCAS activated, it would probably take a few cycles of back and forth before I realized that something was amiss, but I have never been reluctant to trim as necessary. Eventually I would have made my way to the runaway trim NNC, but would have done so from an in-trim state.

This is not to say that everything would have been executed flawlessly (i.e. good chance I would forget to call for gear initially), but then that's why you want an experienced First Officer to back you up. Personally, I feel that the Ethiopian Airline policy of placing low-time pilots in the right seat of a passenger airline borders on the criminally negligent.

So, to flog the topic one more time..... When presented with an undesired and/or unexpected aircraft state, it is absolutely crucial for the pilot flying to be prepared to revert to basic airmanship skills. Set the pitch. Set the power. Trim the aircraft. Monitor the performance. Adjust as necessary. Get to a safe altitude. Stabilize the aircraft. And then work the problem.

None of this requires "sky god" or "test pilot" level of skill. It simply requires making the conscience decision that you are going to fly the aircraft with the tools that are readily available.

[maxter]

737 driver: Do you not train for those failures in a sim. I think that was what was being suggested for MCAS failure, not just an Ipad brief

[737 Driver]

737 driver: Do you not train for those failures in a sim. I think that was what was being suggested for MCAS failure, not just an Ipad brief

It is simply impractical to train for every failure mode in the sim. Even when going through the initial checkout in the 737, a pilot will not see every malfunction that is contained in our non-normal procedures (we used to call them EMERGENCY procedures, but that is a whole different topic). The preamble to our non-normal procedures state explicitly that it is impossible to come up with a checklist for every possible situation, so sound judgement always applies. In a thorough training program, however, you should see a good enough cross section of failures so that you become comfortable with a general process for handling an aircraft malfunction.

Over the years and through several different organizations, I have seen different variations and phraseology of these basic principles, but every single one of them started with the same first step - FLY THE AIRCRAFT. This is so fundamental and so important that at one previous employer we used to say that the first three steps of any emergency was 1) Fly the aircraft, 2) Fly the aircraft, and 3) Fly the aircraft.

Sadly, this concept has to be repeated frequently because, for various reasons, pilots keep forgetting this touchstone principle. FLY THE AIRCRAFT. First, last, and always.

[Flocks]

Hello all.

i just checked one of the previous aircraft I used to fly, equipped with a stick pusher system, this is what I found :

The push force felt at the control column is approximately 80 lbs, which is adequate for stall
correction, but can still be overpowered by the pilot in the event the system cannot be
disabled.
NOTE: The number 1 and number 2 computer must both agree to push before the stick
pusher can be activated.

The stick pusher will activate when all of the following conditions are met:
• #1 STALL SYST FAIL, #2 STALL SYST FAIL and PUSHER SYST FAIL caution lights are
OFF.
• The airplane is airborne.
• The airplane altitude is greater than 400 feet AGL.
• The airspeed is less than 200 -
4 KEAS.
• The stick shakers have been activated by both systems.

The only thing I have difficulty to understand is why Boeing in the first place didn't connect the MCAS system to both AOA, exactly as stick pusher was in my previous aircraft.

​​​​now, not writing as long post about it, but the mcas issue is not only a design problems ... We can clearly see a tendency in the world of pilot to loose confidences in manual and basic flying skill in the modern aviation world. I would like to believe authority will not only react to fix the MCAS and that it, it is applicable to all the aviation world and instead of have more and more automation because pilot are more and more crap, we should maybe put back the pilot in the center of the loop and ask / help / train them to have their skill up to the task.
​​

[HundredPercentPlease]

some very basic airmanship technique

Getting a bit bored of multiple posts slagging off these pilots.

We get it. You think they were sub-standard. You would have used your greater "airmanship" to keep the basic parameters in line and therefore the aircraft flying.

Your lack of appreciation of human factors in a real scenario with real line pilots in the real world is what you should address. After-the-event-heroism is ever so easy.

My suggestion is to slice the event up into small time slices. In each slice - look at the information presented, the probable solution, the required actions and the workload. Then in the next slice, base your model on a modification of the previous slice - increasing or decreasing the factors, and extrapolating the data flows. So if it starts with a stall indication, then keep the "it's a stall" flowing, until (given the workload estimate) the information is sufficient to demonstrate to the pilots that it's not a stall. Doing this, you will discover that the pilot with reduced workload will process new information earlier.

In my model, the captain wanted to get the thing cleaned up, then reduce the workload, then work out what was wrong. They cleaned up - he used the a/p to reduce the workload, and as they were starting to diagnose the aircraft bit them. His workload reduced his SA (along with the stick shaker) to a critical point. The pilot failed due to excess workload, not due to lack of "airmanship".

[HundredPercentPlease]

I am not rude and I asked 3 times...thank you for finally answering that you have no clue how much more training is required.

I have a clue.

This is about:
Systems knowledge
Recognition
Recovery

Systems knowledge
A document/ipad/manual will give the systems knowledge.

Recognition
If the new software were to have an aural alert "MCAS" whenever it triggered, then this would make recognition easy. Because if you are in a phase of flight that is normal, and the machine cries "MCAS", then you know it's a fault and quickly flick the switches. This part would not require sim training.

If the new software does not alert you, then recognition has been demonstrated by two crews as difficult, and therefore this would require sim training. Maybe 3 or 4 scenarios based on different phases of flight and different erroneous inputs.

Recovery
The recovery may require sim training regardless of the above. If you're in a benign state and MCAS activates (and you recognise) then recovery is not hard, and has been previously trained. But what if you are in an expeditious descent (say, 330 knots) and MCAS triggers? You flick the switches. But now you are probably in a slight overspeed, pointing the wrong way, holding against the trim and are faced with hand-trimming. I would suggest that I would like to practice that in the sim, and I'd like the crew of the Max I am in the back of to have also practised that - before I get on board.

So however you look at it, sim training is required. Probably just 1 hour per crew, but 1 hour none the less.
Anything less, I'm not going.

[edmundronald]

A single sensor failure of any kind on any airliner happens every day and is a no-brainer. Except on the MAX, thanks to Boeing and FAA.



Thanks. Can't say it better.

The thing is, a whole set of failures seems to have clustered around MCAS, and Boeing didn't do anything about it, and the FAA is now busily sweeping all of the evidence under the table to protect itself. .

The design of the 737 Max MCAS with two AoA sensors present and only one input used is *wierd*

Edmund

[meleagertoo]

Perfect answer!

Just no mention of it in the fix.

As you are vocal and seems a very competent 737 pilot (certainly seems that way by your posts)

Can you detail how the/you cockpit would have responded after take off of the ET flight with you as Captain and with the 2-300 hr FO - who's job was who's when and why ?



Capt PF, FO PNF
Vee one, Rotate! Stickshaker sounds on rotation. Master Caution and other assorted warnings.
You immediately hit TOGA and check pitch attitude. Almost immediatey see from the aircraft's performance that it is climbing normally and feels normal. You're already somewhat sceptical about the stall-warning. You Tell PNF to crosscheck airspeeds.He does so and his and the SBY agree. You now know the warning is false. "Gear UP" "You have control, FLY the aeroplane Bloggs! climb maintain 10,000ft (at Addis), level at 200Kts do not retract flaps, my RT". Scan panel and assay the warnings. Looks like unreliable airspeed is the first to deal with. Memory items - Assure yourself the aircraft is indeed flying normally. Monitor the FO, tell him to reduce power if necessary, you don't need 5000fpm at this point. Once comfortable-ish locate of the stickshaker cb and pull it. (it was drilled into us at my 737 conversion that you need to be able to find that one quickly just to reduce stress levels once it is deteremined to be false).
Pan/Mayday call for radar circuit to land 15 mile finals to give us time.

I really don't think I'd retract flap in that situation. I don't know what's caused the stickshaker and associated stall warnings but I do know the airframe seems to be flying as normal. I'd like to think I had the wit not to disturb anything that might affect that and leave flap where it is. I'm going to need it in a few minutes time for landing, why retract? It's just addng another potential unknown into the mix and I'd simply rather avoid that altogether. Accuse me of being wise after the event if you like, but my first thought on reading the sequence of events was "why did they move the flaps?"
Let's assume I did raise the flaps and MCAS set off on it's tricks. By now the stickshaker has been shut up and we can think. We level at 10,000 clean and speed 250. Bloggs says the bloody trim keeps running forward and he has to keep motoring it back. This is weird. What the heck's going on? You watch it for a couple of cycles and it seems the automatic trim is doing things that are unasked for and unwanted. How is this difficult to contain - even if your company hadn't told you about LionAir, Boeing's STC and you were such a hermit you didn't read the news or discuss tech in the crewroom?
"Bloggs, we're going to revert to manual trim, tell me when you're in trim and I'll select the cutout switches. (I might even take control for a minute or two to see what he is experiencing.)
There isn't much of an existential threat in any of this, is there? Apart from a little sphyncter exercise in the first ten seconds after rotation once the stickshaker is silenced this can all be done in a conversational tone of voice, which is how I prefer to manage malfunctions.
Bloggs flies the circuit. Capt runs checks, briefs landing, talks to No1 and pax, takes control and lands normally if perhaps a bit overweight.

UNLESS - the big unless - you don't stop the stickshaker beating your brains to mush and you don't forget to fly the aeroplane (so runaway airspeed doesn't happen). I think this step is critical in creating an environment where logical thought can once again occur. No overspeed, trim still operable even if you did select cutoff switches before getting it somewhere cloise to normal.
That done, you land. No one dies. No hysterical outbursts in the media shrieking about Boeing's corporate greed and murderous incompetence, or the wicked complicity with the FAA and crooked approval standards. MCAS gets fixed relatively quietly - probably still with a fleet grounding - and all returns to normal. Most importantly, the airframe is intact and they can see what ent wrong right away.
Boeing perhaps adds a stickshaker cutoff switch to the panel somewhere...to aid those whose instructor wasn't as punctilious as mine. Thank you Al.

Having flown extensively with 200hr cadets fresh to the line in a major UK airline I'd not be much concerned about my colleague's (in)experience. Of course I can't comment on those from other training environments. In my experience he is probably as good as you at flying the aeroplane accurately, probably has at least as good if not better tech and systems knowledge so use him as a voice-activated autopilot as Mr Boeing expects you to do. At my conversion course we were told that Boeing's design philosophy was that the aeroplane was designed to be operated by a competent Professional pilot and an (insert name of continent) PPL. It does that as advertised. Ultimately a sucessful outcome hinges on that, and that alone. If other nations employ different standards of crew training and operating standards then this premise becomes faulty (through no fault of Boeing's) and all bets are off.

All the above only relevant If you stick to the correct procedures and employ a tad of (swearword alert) A!*m@n***p.

You are certianly in a different pickle if your company hasn't troubled to pass on the latest Boeing safety advice or promulgated lessons learned from the previous accident, but then why wouldn't any pilot on the same type take the trouble to find out himself - as if you could avoid learning all about it in the media - so how could they not have had an inkling that this was all deja-vu? I know Ethiopia is a bit insular but for heaven's sake!

A proper Western investigation into Ethiopian's operating and training standards would make interesting readng but that's not going to happen. We'll be lucky to get an unmolseted CVR which would tell us what really went on. I fear the final report may not tell us much useful at all.

[Chu Chu]

I find it fascinating to watch highly qualified and experienced folks take nearly opposite views of the crews’ and Boeing’s respective contributions to the accidents.

I wonder if folks might get closer to consensus if the judged the crews based on what did happen, and Boeing on what could have happened. As SLF, I have to accept that the chaos in the cockpit would have been beyond anything I’m capable of imagining. But I’m still skeptical that a crew trapped in a tug-of-war with the control column shouldn’t have worked out that they should apply nose-up trim – and keep applying it until things got better or it became completely obvious that it wasn’t working.

At the same time, I’m assuming that the AOA probe failure could have happened in IMC. At least I haven’t seen anyone explain why it couldn’t. It seems perfectly reasonable that a crew faced with a stick shaker for no obvious reason and a display showing the horizon rising above the flight path for no obvious reason might hesitate before making major nose-up control and pitch inputs. And it sounds like it could have become too late pretty quickly.

Am I missing something?

[double-oscar]

Getting a bit bored of multiple posts slagging off these pilots.

We get it. You think they were sub-standard. You would have used your greater "airmanship" to keep the basic parameters in line and therefore the aircraft flying.

Your lack of appreciation of human factors in a real scenario with real line pilots in the real world is what you should address. After-the-event-heroism is ever so easy.

My suggestion is to slice the event up into small time slices. In each slice - look at the information presented, the probable solution, the required actions and the workload. Then in the next slice, base your model on a modification of the previous slice - increasing or decreasing the factors, and extrapolating the data flows. So if it starts with a stall indication, then keep the "it's a stall" flowing, until (given the workload estimate) the information is sufficient to demonstrate to the pilots that it's not a stall. Doing this, you will discover that the pilot with reduced workload will process new information earlier.

In my model, the captain wanted to get the thing cleaned up, then reduce the workload, then work out what was wrong. They cleaned up - he used the a/p to reduce the workload, and as they were starting to diagnose the aircraft bit them. His workload reduced his SA (along with the stick shaker) to a critical point. The pilot failed due to excess workload, not due to lack of "airmanship".


But your model is not what is contained in the QRH for the Boeing 737. There are actions for a stick shaker on lift-off and neither involve engaging the auto-pilot or retracting the flaps. One would hope any pilot flying the aircraft would be familiar with this. Certainly in EASA countries, jet upset and stall recovery has been one of the hot topics and recurrent training for the past few years has certainly included elements to improve pilot recognition and recovery from such events. To focus on MCAS is wrong, there is much more to these accidents than that and 737driver is right, pilot training is one of them.

[Loose rivets]

wonkazoo #4412

I thought, a very good post with an up to date overview of the situation in general.


737Driver #4438

By the numbers then: Stick shaker. WTF?! Check my power (increase as necessary), check my attitude, check my configuration. Is it flying or is it wallowing? ( my bold ) If it is wallowing, keep the nose down and accelerate.

Over the years since the 447, I've become seriously concerned about the lack of aerodynamic feel the Children of the Magenta line seem to display. I was instructed to take the BAC 1-11 to the push every other base check and remember with astonishing clarity how that aircraft felt. Hand flying to and from the cruise was taken for granted. No sims then.

A British Eagle training captain took a fellow FO and me to STN for some Viscount familiarization. One of the fun things was going over the end of the runway at 1,500' (yes, on QFE) and landing off that. We'd both been on it a year by then and it was just a fun thing to do. I can not imagine being restricted to simulated flight to get to know a type. I can not imagine being in the RHS never having really pulled the aircraft about. Mind you, we flew a lot of empty sectors back then which did not please the bean counters.

On the loss of vision thread, someone piped up and said, that's what the bloke in the RHS is for. Just go somewhere and land. Yeh, right. Good luck with the weather.

I'd have no problem stepping onto a MAX with 737Driver at the helm. But, he is pre-sprung to react to the smaller anomalies, but I'm still concerned by that 'noise' on the thumb switch trace, instead of a clear sustained ANU command. As mentioned, I'm still concerned about another 'ghost in the machine' computer anomaly.

I'd still step onto a flight was several of the experienced bods on this thread, but I wouldn't discount the chance of the craft delivering a WTF! moment.

[Smythe]

I would like to see a brand new FMS, not version 14 with all the legacy bs hiding in the background.
A good flow chart of the connectivity and flowpath with the if/then clearly shown. Now there is not only the if/then, but the legacy but if, but if, but if, then.

B 737 driver....In regards to the MCAS and AP, there seems to be some differences noted.
From Pilot reports:

Wind and mechanical turbulence was noted. Careful engine warm times, normal flaps 5 takeoff in strong (appeared almost direct) crosswind. Departure was normal. Takeoff and climb in light to moderate turbulence. After flaps 1 to "up" and above clean "MASI up speed" with LNAV engaged I looked at and engaged A Autopilot. As I was returning to my PFD (Primary Flight Display) PM (Pilot Monitoring) called "DESCENDING" followed by almost an immediate: "DONT SINK DONT SINK!"
I immediately disconnected AP (Autopilot) (it WAS engaged as we got full horn etc.) and resumed climb.

Another report:

After verifying LNAV, selecting gear and flaps up, I set "UP" speed. The aircraft accelerated normally and the Captain engaged the "A" autopilot after reaching set speed. Within two to three seconds the aircraft pitched nose down bringing the VSI to approximately 1,200 to 1,500 FPM. I called "descending" just prior to the GPWS sounding "don't sink, don't sink." The Captain immediately disconnected the autopilot and pitched into a climb. The remainder of the flight was uneventful.

Over the years since the 447, I've become seriously concerned about the lack of aerodynamic feel the Children of the Magenta line seem to display.

Concur, but, as we have all noticed, the ac these days are getting pretty slippery, not to mention a lot more thrust.. its not as easy...been a bit surprised on some short finals.

[GordonR_Cape]

I find it fascinating to watch highly qualified and experienced folks take nearly opposite views of the crews’ and Boeing’s respective contributions to the accidents.

I wonder if folks might get closer to consensus if the judged the crews based on what did happen, and Boeing on what could have happened. As SLF, I have to accept that the chaos in the cockpit would have been beyond anything I’m capable of imagining. But I’m still skeptical that a crew trapped in a tug-of-war with the control column shouldn’t have worked out that they should apply nose-up trim – and keep applying it until things got better or it became completely obvious that it wasn’t working.

At the same time, I’m assuming that the AOA probe failure could have happened in IMC. At least I haven’t seen anyone explain why it couldn’t. It seems perfectly reasonable that a crew faced with a stick shaker for no obvious reason and a display showing the horizon rising above the flight path for no obvious reason might hesitate before making major nose-up control and pitch inputs. And it sounds like it could have become too late pretty quickly.

Am I missing something?

I raised the possibility of faulty AOA and MCAS activation during night IMC conditions many pages ago, but there were no bites to my suggestion. If you throw in somatogravic illusion, the outcome could only have been more difficult than the two (three) actual cases that occurred in daytime VMC conditions. Juggling flight controls, instrument displays and spatial orientation at once would a real handful.

You comment raises a broader issue: With hindsight we know that both aircraft were flyable, with the right sequence of control inputs. At the time the pilots could not have known this for sure, and may have wasted energy on many mental scenarios, most of which did not lead to the small number of escape steps. They did not know for certain if there was any kind of mechanical malfunction (parts of the horizontal stabiliser or elevator fell off, control systems jammed), computer gone rogue (we know the cutoff switches are supposed to work, but are you really sure). In addition they might conceivably avoid doing things that might make the situation worse, or provoke the computer systems into more nose-down trim?

As several personal anecdotes have reminded us, when things go seriously wrong, rational thought sometimes goes right out the window. My understanding is that passenger jet pilots do not wake up in the morning expecting to face imminent death. The training process does not emphasise this kind of life or death situation, and the selection process does not specifically weed out those that would fail to meet test-pilot or astronaut standards.

[737 Driver]

B 737 driver....In regards to the MCAS and AP, there seems to be some differences noted.
From Pilot reports:

Wind and mechanical turbulence was noted. Careful engine warm times, normal flaps 5 takeoff in strong (appeared almost direct) crosswind. Departure was normal. Takeoff and climb in light to moderate turbulence. After flaps 1 to "up" and above clean "MASI up speed" with LNAV engaged I looked at and engaged A Autopilot. As I was returning to my PFD (Primary Flight Display) PM (Pilot Monitoring) called "DESCENDING" followed by almost an immediate: "DONT SINK DONT SINK!"
I immediately disconnected AP (Autopilot) (it WAS engaged as we got full horn etc.) and resumed climb.

Another report:

After verifying LNAV, selecting gear and flaps up, I set "UP" speed. The aircraft accelerated normally and the Captain engaged the "A" autopilot after reaching set speed. Within two to three seconds the aircraft pitched nose down bringing the VSI to approximately 1,200 to 1,500 FPM. I called "descending" just prior to the GPWS sounding "don't sink, don't sink." The Captain immediately disconnected the autopilot and pitched into a climb. The remainder of the flight was uneventful.


I haven't seen the original reports (would appreciate a pointer to the source if someone has it), but I saw this discussed elsewhere. It had been pointed out that this is likely two reports for one incident - one by the Captain and one by the FO. It is quite common for both pilots to fill out separate reports.

This does not appear to be a MCAS issue, since the A/P was engaged. It is more likely an autopilot issue. Not knowing the detail of how the crew had the A/P set up or the maintenance history, I couldn't really comment beyond that. I've seen A/P doing wonky things before on engagement which is why I keep my thumb near the disengage button when turning the ship over to HAL.

[737 Driver]

We get it. You think they were sub-standard. You would have used your greater "airmanship" to keep the basic parameters in line and therefore the aircraft flying. Your lack of appreciation of human factors in a real scenario with real line pilots in the real world is what you should address.

Applying the steps I have outlined is not "greater" airmanship. It is basic airmanship. These steps have been preached in aviation circles pretty much since the Wright Brother days. I really don't understand why this is such a difficult or controversial topic.

I definitely appreciate the human factors issue. The crew performance is one HUGE human factors issue. And that issue is this: What were the factors impacting these crews (experience? training? environment? stress?) that kept them from applying basic airmanship skills to stabilize the aircraft so they could then successfully deal with the malfunction?



In my model, the captain wanted to get the thing cleaned up, then reduce the workload, then work out what was wrong. They cleaned up - he used the a/p to reduce the workload, and as they were starting to diagnose the aircraft bit them. His workload reduced his SA (along with the stick shaker) to a critical point. The pilot failed due to excess workload, not due to lack of "airmanship".

Here's the hard reality: "Your" model (or the ET Captain's model, if you rather) resulted in the deaths of all the passengers and crew. There is not a single universe in which selecting A/P at low altitude was the right choice with an active stick shaker. Raising the flaps prior to properly diagnosing the problem is also highly suspect. What I see instead is a Captain who was so unclear as to what was going on that he simply reverted to what he did on every previous takeoff - engage the A/P at 400', climb to 1000', retract the flaps. Trimming was handled poorly because he had not hand-flown sufficiently to wire this skill into procedural memory. This was not airmanship, this was rote behavior.

In comparison the "model" I have repeated flogged, a model that has been around for probably a century of aviation, a model that has saved many an aircraft when followed and doomed quite a few when not, would have at a minimum allowed this crew to stabilize the aircraft and get it to a safe altitude. Whether they would then have correctly resolved a subsequent problem with MCAS is impossible to say, but they would have been dealing with it from a stabilized platform at a much higher altitude.

[Organfreak]

737 Driver:
What you say (and keep on saying) makes manifest sense. Basic competency is an absolute requirement for this gig.
Don't let the bastards get you down!

[Cows getting bigger]

Trying to add a bit of balance here, there are clearly polarised views regarding Boeing vs. a few pilots. Surely professional aviators, certainly those operating a $100M aircraft, realise that they are a layer in the system? What would you prefer, no changes to the technical side and continued reliance on pilot skills/airmanship, or perhaps a more comprehensive review and upgrade of the entire system (note, pilots are part of the system)? To bang-on about a lack of basic airmanship sort of misses the point and reminds me of the 1980s Air Force I joined. Things have moved on. If it were my train set(s), I would:

Start designing the 737 replacement
Bin the MCAS 'kludge' and put in a system that is far more comprehensive and capable.
Ensure people are trained properly (a joint manufacturer, regulator and operator responsibility)
Communicate.

We all have positives to offer here and that should be a good thing about aviation. Unfortunately, money drives the world; the open & honest environment we require will always be influenced by the bean-counters and lawyers.

[edmundronald]

Trying to add a bit of balance here, there are clearly polarised views regarding Boeing vs. a few pilots. Surely professional aviators, certainly those operating a $100M aircraft, realise that they are a layer in the system? What would you prefer, no changes to the technical side and continued reliance on pilot skills/airmanship, or perhaps a more comprehensive review and upgrade of the entire system (note, pilots are part of the system)? To bang-on about a lack of basic airmanship sort of misses the point and reminds me of the 1980s Air Force I joined. Things have moved on. If it were my train set(s), I would:

Start designing the 737 replacement
Bin the MCAS 'kludge' and put in a system that is far more comprehensive and capable.
Ensure people are trained properly (a joint manufacturer, regulator and operator responsibility)
Communicate.

We all have positives to offer here and that should be a good thing about aviation. Unfortunately, money drives the world; the open & honest environment we require will always be influenced by the bean-counters and lawyers.

As an engineer, I would say that MCAS was not a money issue, it was a management/corruption issue.

In an ideal world, the regulator and the manufacturer, FAA and Boeing would have sat down for a discussion of how to solve the issue MCAS addresses, stated requirements, a proposed solution, and a validation path to ensure the adequacy of the solution. Because MCAS is ABOUT EXTENDING AN EXISTING TYPE CERTIFICATE.

In the corrupt world which has set in, the FAA said nudge nudge wink wink "just make a fig leaf to cover that patch", Boeing designed a fig leaf, flight tested it and found it inadequate, quickly modded it and shipped it. No dialogue and honest verification took place.

Now the FAA, and thus the US government is involved in covering up the process inadequacy "in the name of competing with Airbus".

What a joke. Don't congressmen and women have families who fly on US-made airframes?

Edmund

[LowObservable]

So as this thread continues towards the five-grand mark, how many of these posts have been a version of "well, if this had happened to me and my F/O, we'd have done this, that and those other things and everyone would have been fine because FLY THE AIRPLANE and BASIC AIRMANSHIP and we're not children of the magenta line, we're hairy-armed master aviators."

But let's get this straight. It never happened to you.

There are three pilots alive to whom this failure (AoA failure arms MCAS, which kicks in as flaps retract) actually happened. Four others are dead along with their passengers, The failure caused two fatal accidents less than two years after service introduction. Compare this to anything in the past 25 years of aviation and tell me that's not unusual, that the AoA/MCAS sequence is something that should be handled with normal training.

Bull:mad:!

[Organfreak]

Compare this to anything in the past 25 years of aviation and tell me that's not unusual, that the AoA/MCAS sequence is something that should be handled with normal training.

Bull:mad:!

What about the 737 rudder problems [hardovers from defective actuators]? IIRC, that problem, besides a mechanical one, had to be "trained" for a technique to avoid going splat.

But the guy you're railing against, the one who keeps on saying, "Fly the airplane," DOES acknowledge the design problem generated by Boeing, in every post, while criticizing the pilots. That IS a balanced view.

[dccraven]

I just saw this on The Aviation Herald:

On Apr 27th 2019 it became known, that four independent whistleblowers, current and former Boeing employees, had called the FAA hotline for whistleblowers regarding aviation safety concerns on Apr 5th 2019. The concerns reported were wiring damage to the AoA related wiring as result of foreign object damage as well as concerns with the TRIM CUTOUT switches. The FAA believes these reports may open completely new investigative angles into the causes of the two crashes in Indonesia and Ethiopia.

[PerPurumTonantes]

By the numbers then: Stick shaker. WTF?! Check my power (increase as necessary), check my attitude, check my configuration. Is it flying or is it wallowing? If it is wallowing, keep the nose down and accelerate. If its flying, probably a false indication, continue the climb, call for the gear. Cross check instruments. I've got my hands full, so ask my FO to read off what he sees on all three airspeeds. At 400 feet check my roll mode, have FO ask for straight ahead if appropriate and declare emergency. If by now I've determined we have unreliable airspeed, memory items except I'm going to keep takeoff power and 15 degrees pitch until 1000' where I set 10 degrees and 80% N1.
Very convincing, well written, and no-one can argue that following that recipe would have saved the aircraft.

There are two problems with it. The pilot seems to have done rather a lot by 400ft. And leaving flaps down seems a bit too convenient. If you just add a bit of delay in pulling the stick shaker CBs, and you happen to clean up (which would be perfectly good airmanship), then the MCAS genie is out of the bottle and you're in test pilot mode.

Reality is more complex, time is more flexible, cognitive skills are worse than the scripts that we write after the event.

A competent pilot showing good airmanship would most likely have activated mcas pre lion air, and quite possibly post. Once in the mcas trap I'd say it's 50/50 they'd get out of it at low altitude. See my previous post for why. So your constant assertions of 'just fly the plane' don't really cut it.

Again I think everyone agrees with you that there needs to be more emphasis on hand flying skills throughout the whole industry and that 200h is ludicrous for a FO.

[dozing4dollars]

One thing is certain, the persons who are the main drivers of these accidents had a lot more time to consider the outcome of their actions than the pilots. They have a CPA, MBA and/or JD. They received large salaries and bonuses. They live in the suburbs of Chicago, and will be receiving far less scrutiny than the engineers and pilots. They will cost out the lives lost vs. the cost of doing things properly. Their profession will insulate them from their true share of the culpability. In the end a very few will get a golden handshake and pursue other interests. Let’s take a minute to remember them.

[dozing4dollars]

.... and now, because this is a pilots forum, the subject of Airspeed. Although a lot was going on, it seems to me, sitting on my couch, that if A/S was controlled, the misbehaviour of the trim would have been easier to deal with at a lower A/S.

The previous LionAir flights controlled A/S (obviously). When we “hand fly” (flight directors and auto throttle on) it’s analogous to me on my couch. Fly toward the FD. Hell, I even have a Heads Up display. If you want to see the other guys squirm, turn off the AT ;) Much of this so-called “hand flying” isn’t really. I think it would be very human to miss the AS during an event such as this. I think pulling the throttles back once unreliable AS was identified would be key to gaining some time to think. Hand flying with AT on isn’t doing much good and has made me less aware of flying using the throttles.

I also believe the MCAS was not adjusting its trim input for AS. From what I’ve read in the discription of MCAS, it shouldn’t have been using 2.5 degree ANU at higher AS

[Kerosine]

200 hour FOs? A culture of maximum automation at all times with almost zero handflying experience and confidence?

Sounds more like Europe than Africa.

​​​

[737 Driver]

But let's get this straight. It never happened to you.


True, none of us were there when the pins all lined up. Guilty as charged.

Might I also point out that none of us were there when the aircraft designers were designing, the project managers were managing, the regulators were regulating, and the airlines were training. Yet, there seems to be a pretty broad consensus in these parts that their were critical lapses in those parts despite the fact that no one here (at least that I've seen) has claimed to be current in qualified in those specialties. Odd, don't you think?

No, I was not there, and no I have never seen an MCAS failure in the sim or in life. However, over the course of 35+ years in aviation and perhaps a dozen different aircraft, I've dealt with more emergencies in the sim than I can count and more in the air than I ever wished to have had. I've encountered pilots of all different skill levels, and I've observed the traits that separate the good from the bad. Having reviewed perhaps hundreds, if not thousands, of incident reports over the years, I think I have a fairly good sense for what types of malfunctions should have been survivable without resort to extraordinary means, which ones required some combination of luck and superior skill, and which ones were pretty much hopeless from the start. In the case of Lion Air, I'd put that one somewhere between the first and second categories mainly due to the novelty. For Ethiopian, that one falls squarely in the first batch. Sorry you disagree, but I strongly suspect the final accident reports will fall closer to my position than yours.

[MurphyWasRight]

Having reviewed perhaps hundreds, if not thousands, of incident reports over the years, I think I have a fairly good sense for what types of malfunctions should have been survivable without resort to extraordinary means, which ones required some combination of luck and superior skill, and which ones were pretty much hopeless from the start. In the case of Lion Air, I'd put that one somewhere between the first and second categories mainly due to the novelty. For Ethiopian, that one falls squarely in the first batch. Sorry you disagree, but I strongly suspect the final accident reports will fall closer to my position than yours.

In the Ethiopian case unfortunately I would have to disagree with you, the chances of an unbiased look at pilot actions and training are low given the response to the prior (Lebanon) accident report which detailed numerous pilot errors, with a possibility of subtle PIC incapacitation to which Ethiopian authorities strongly objected and proposed unsupported by facts alternate theories.

This illustrates yet another factor of national/corporate pride hindering global safety objectives, and yes Boeing/FAA are in same category.

[flash8]

One thing is certain, the persons who are the main drivers of these accidents had a lot more time to consider the outcome of their actions than the pilots. They have a CPA, MBA and/or JD. They received large salaries and bonuses. They live in the suburbs of Chicago, and will be receiving far less scrutiny than the engineers and pilots. They will cost out the lives lost vs. the cost of doing things properly. Their profession will insulate them from their true share of the culpability. In the end a very few will get a golden handshake and pursue other interests. Let’s take a minute to remember them.

And ain't that the truth.

[737 Driver]

There are two problems with it. The pilot seems to have done rather a lot by 400ft.

No more than I do on any other takeoff emergency. I get to practice several of these a year during recurrent training, and it’s a pretty standard drill to focus primarily on these basic parameters until you get some altitude under you.

And leaving flaps down seems a bit too convenient.

It’s more habit than convenience. My general practice on any takeoff emergency is to leave some flaps hanging unless a procedure calls for otherwise until such time that I determine that I will not be returning to the departure field. This slows things down considerably and burns fuel quicker.

If you just add a bit of delay in pulling the stick shaker CBs, and you happen to clean up (which would be perfectly good airmanship), then the MCAS genie is out of the bottle and you're in test pilot mode.

Sure, I’ll play along. Of course, you’ll have to assume I haven’t put on the A/P by now, and since I’ve pulled the stick shaker circuit breaker (not procedure, BTW, but I’d be inclined to do it anyway) and finished the Airspeed Unreliable NNC, there would be no reason not to ask HAL for some assistance. So, there I am hand-flying, bring the flaps up, and BAM!, MCAS kicks in. What MCAS will then attempt to do is run the trim nose down for 9 continuous seconds and spin the trim wheel about 37 times. I’ve asked this before, and I’ll ask this again: Starting from a stabilized, in-trim platform, exactly how long should a qualified 737 type-certified Captain who is hand-flying the aircraft let the trim run in one direction before he/she does something about it?

Therein lies your answer. What you have at this point is runaway stab trim. Our procedures really don’t care what the source of the runaway is. If you have an undesired and unexplained stab trim input, you are expected to intervene.

Reality is more complex, time is more flexible, cognitive skills are worse than the scripts that we write after the event.

Again I think everyone agrees with you that there needs to be more emphasis on hand flying skills throughout the whole industry and that 200h is ludicrous for a FO.

I do not disagree, but there really is a limit to how much befuddlement should be expected of a professional flight crew entrusted with the lives of 150+ souls. If a pilot cannot overcome the initial surprise factor in pretty short order, fall back on basic airmanship skills and execute known procedures, then perhaps they should reconsider their chosen career.

[meleagertoo]

So, there I am hand-flying, bring the flaps up, and BAM!, MCAS kicks in. What MCAS will then attempt to do is run the trim nose down for 9 continuous seconds and spin the trim wheel about 37 times. I’ve asked this before, and I’ll ask this again: Starting from a stabilized, in-trim platform, exactly how long should a qualified 737 type-certified Captain who is hand-flying the aircraft let the trim run in one direction before he/she does something about it? Therein lies your answer. What you have at this point is runaway stab trim. Our procedures really don’t care what the source of the runaway is. If you have an undesired and unexplained stab trim input, you are expected to intervene.


I do not disagree, but there really is a limit to how much befuddlement should be expected of a professional flight crew entrusted with the lives of 150+ souls. If a pilot cannot overcome the initial surprise factor in pretty short order, fall back on basic airmanship skills and executed known procedures, then perhaps they should reconsider their chosen career.


+100
Oh? Ten charaters minimum? +100,000,000 then

[Smythe]

I haven't seen the original reports (would appreciate a pointer to the source if someone has it)

737 Driver ASRS database link.. https://asrs.arc.nasa.gov/overview/database.html

[737 Driver]

737 Driver ASRS database link.. https://asrs.arc.nasa.gov/overview/database.html

Found them, thanks! The reports were misfiled with the 737NG's for some reason. They appear to be reporting the same anomaly. Report numbers are ACN 1597286 and ACN 159380 for anyone looking for them.

[HundredPercentPlease]

OK, first post, and not a pilot. But I have read all posts here. Simple question. If the pilots of Lion Air 610 and Ethiopian Airlines 302 had been flying Airbus A320s would these accidents have happened? I am a frequent passenger (I hate TLAs, especially SLF - we simply pay your wages after all) so I would like to have some objective feedback.
The 737 Max uses one AoA vane, and if it fails a world of hell ensues.

The A320 uses the two best of three vanes, so discarding the faulty one. This makes a fault very unlikely. However, it has happened! 2 froze in a fixed position causing the aircraft to pitch down (it thought those 2 were correct and the 1 truly correct one was incorrect). The pitch down was overcome by the pilots using half backstick. They then worked out the two side by side buttons that needed switching off to correct the situation.

Since then Airbus underwent a huge program to ensure pilots knew how to recognise the problem (you can catch it well well before it pitches you down) and which two buttons to press. Google: OEB48. The issue has now been engineered out and I don't think it happened a second time.

The A320 is a proper FBW aircraft that has been pottering around since the 80s. The max is a conventionally controlled aircraft with a bit of totally inadequate FBW bolted on, to fix a fundamental aerodynamic problem that would be forbidden if the aircraft was new.

And yes, I received sim training to recognise and recover from an OEB48 event.


Incident: Lufthansa A321 near Bilbao on Nov 5th 2014, loss of 4000 feet of altitude (http://avherald.com/h?article=47d74074)

[DaveReidUK]

737 Driver ASRS database link.. https://asrs.arc.nasa.gov/overview/database.html

Report Numbers (ACNs): 1597380, 1597286. Neither was an MCAS-related event; there are none in ASRS.

[Thrust Augmentation]

Excuse the length & potential ignorance;

I'm still really, seriously struggling to get my head around the specifying of MCAS & it's method of operation. It's apparently there to increase feel at high AOA, but its driving a primary flight control surface. I understand that increasing feel at increasing AOA is necessary for certification requirements & I understand that feel reduces as AOA increases in the MAX due to the additional lift generated by the larger, repositioned engine cowlings.

So, for whatever reason, MAX reaches high AOA which isn't indicated as is normal by stick feel - Pilot needs to be informed of the situation - this part seems to be neglected / skipped & dubious automation takes over & starts driving the big guy at the back. Why does the requirement for increased stick force / feel to the pilot morph immediately into a substantial control surface deflection?

I'm seeing it that MCAS is doing nothing to meet the certification requirements of increasing feel, but rather forcefully avoiding the flight regime where the certification requirement exists - "don't go there" rather than "we are approaching there"


In my simplistic terms, I have a car that has lightening steering input as steering angle increases - it makes it a bit misleading to drive & the feel isn't right;

In my garage & in an ideal world the steering system is redesigned so that it works in the generally accepted manner. In a less ideal world, due to cost or time constraints a damper or progressive restrictor of some form is added. Either will resolve the issue & give the desired feel.

In the Boeing garage, skip the feel issue & add in a hidden & complex system that powerfully steers the car in the opposite direction of what's requested when the steering angle gets high. Control this complexity from a steering angle sensor which is know to be susceptible to damage & occasional failure. This is not adding feel, its taking control & in a questionable manner.

The more that I think about this something tells me that the characteristics of the MAX in the high AOA regime may have more issues than simple feel alone - hence the utilisation of a pile driver to crack what is apparently a nut.

[gums]

Salute!
@Ricky Answer to your original question is easy----- NO!

@Thrust... Great analogy with the power steering. I used that same one with my wife. Last thing I want, and sje agreed, was the power steering to get easier the more I turned the wheel. And the auto folks figured this out back in the late 50's. My first experience with an inlaw's car was a surprise. But within a few years we had better control valve configurations and then some inputs from speed. Hmmmm..... starting to sound like some airplane systems intended to "help" as well as keep the pointy end forward.

Back at Ricky and Thrust........ It ain't "feel". It's the basic aero characteristic of the MAX when at high AoA. So they called it "Maneuvering CHaractersitic .........." Unlike previous versions, this new critter had less inherent aero resistance to increasing AoA than required/desireable. In other words, it could be possible that eventually your AoA might keep increasing while you had the yoke/column/stick neutral. Not good.

The Boeing fix was not to screw with the "feel". Instead, by moving the stab, then the existing flight control stuff could save the day and the plane would pass the certification requirements. Although intended for high altitude and maneuvering flight, the accident MCAS scenarios happened at low altitude and slow speed and at the tail end of a critical phase of flight. Oh yeah........ the damned wheel was shaking like crazy and there were various warning lights.

In the 'bus, there is a last ditch feature called "direct law". So even if the AoA data and air data is FUBAR, your stick movement will command control surface movement at some default ratio. It's like the cable/pulley/pushrod stuff our 737 golden arms talk about. It's like your auto power steering as far as you can tell. And the 'bus is more aerodynamically capable of meetinfg the cert requirements due to its basic design, unlike the new 737 MAX.

Gums.....

[Smythe]

Found them, thanks! The reports were misfiled with the 737NG's for some reason.

There are far more than 2 reports.

The search is tough, one has to search the different variants with what is reported in the ASRS system. (there is no 737-8MAX, etc)
So far, there are reports under, 737-800, B737 Next Generation Undifferentiated, and B737 Undifferentiated or Other Model..

the nomenclature of this model has created some issues.

[FrequentSLF]

Salute!

In the 'bus, there is a last ditch feature called "direct law". So even if the AoA data and air data is FUBAR, your stick movement will command control surface movement at some default ratio. It's like the cable/pulley/pushrod stuff our 737 golden arms talk about. It's like your auto power steering as far as you can tell. And the 'bus is more aerodynamically capable of meetinfg the cert requirements due to its basic design, unlike the new 737 MAX.

Gums.....
First of all thanks for your posts, I found them very instructive.
i have a question that has been in my mind for very long. Does any other commercial airframe needs a software patch to pasd a certification requirement? Or to a certain extent certification was designed with software patches as remedies?

[Bend alot]

In a statement to CNN, the FAA claims that they knew that MCAS would cause a stabilizer runaway but they just expected pilots to deal with it. (https://www.cnn.com/2019/04/26/politics/faa-hotline-reports/index.html)


My question for the FAA representative would have been "if you had found some faulty hardware component on a 737 that increased the risk of a trim runaway, would you have directed airlines to fix it, or would it be OK because pilots know how to deal with it?"

Engine shutdown on takeoff? No prob, pilots are trained for that one. Dual failure over water? Hey, it worked for Sully! There is a lot about my country that I no longer recognize, and our engineering safety culture seems to be the latest casualty of whatever infection is messing with our brains. I'm waiting for one of the talking heads to inform us that randomly pitching the nose down on rotation is actually a good thing because it keeps the pilots from getting bored and lazy!



CNN response should have been - Then why have you grounded the 737 MAX?

And why is the 767 tanker MCAS so different to the MAX- anything to do with training required?

[wonkazoo]

.

I'm not cutting Boeing, the FAA, or the airlines any slack for their role in these accidents. They all need to address their lapses. But as I've already stated, this is not a forum for Boeing. Or for the FAA. Or for airline managers.​​​​​​ We don't really have the power to address their issues. We do have the power to address ours.

This is a forum for professional pilots. Yes, we could sit back, point fingers, and opine about how badly someone else screwed up. Or we could take a hard look at our profession and ask why multiple crews had such difficulty and/or reluctance in applying some very basic airmanship techniques to resolve an aircraft malfunction that, while being unique and baffling, ultimately did not render the aircraft unflyable.

Specifically to your point about being a forum for professional pilots. You are completely correct. Professional pilots who fly airplanes made and certificated by large companies and in the US the FAA. If this isn't the place to opine about a substandard or frankly lethal product being provided to you on which you will earn your living I don't know what is.

Look, I agree with pretty much everything you say, up to the point where it was the crews' fault for what happened. They had no control over their training. They had no control over Boeing's clear abuse of the certification process, and they had no input on a system which (as I have described previously) would try to kill you if you didn't get the diagnosis right. And that's an important distinction. In an earlier reply you spoke of numerous failures that you experienced which were nearly catastrophic. IIRC you mentioned engine failures as an example of a potentially fatal event. The problem is twofold: First, you need engines to fly. Like, I mean, you can't live without them right?? And second: Yes, an engine failure can be (and many times is) fatal. But it doesn't have to be, and if you goof a little bit the outcome isn't a 100 percent fatal conclusion. Even if you goof a lot the outcome is frequently far less than fatal.

If an engine failure happens there are a gazillion possible outcomes, all of which rely on you, the pilot, to select and control the final result.

But with MCAS there are only two possible outcomes, one is you keep flying if you line up the dots within roughly a minute (40 seconds if you believe media reports) the other is you are d-e-d dead.

I know of no other binary system/operational outcome that aligns with this and I once again submit this to the community: Anyone got an equivalent they can share??

Here is another attempt to try to illustrate how unique this circumstance is, and how profound Boeing's errors were in bringing this airplane forward for commercial use. (And how culpable they are as a consequence)

Imagine if your airplane had a third, previously unneeded engine that contributed nothing to the performance, stability, safety or functionality of the aircraft. I'm even going to give us the benefit of the doubt and say you know this third engine exists. If engines 1 or 2 fail you just do everything like you always have. Pull out the proper checklist, do your memory items and find someplace to land. But if engine #3 fails, well then you have 30 seconds to a minute to identify the correct engine, diagnose it and shut it down using an exact mechanism that has zero tolerance for deviation. If you fail to do this exactly right your third engine explodes and rips off the tail in the process and you and your airplane are toast on a stick.

That's what I mean when I say MCAS will try to kill you (it will...) and that's why I believe this is a unique circumstance and finally: That's why I place the responsibility for the entirety of the outcome for both flights at the feet of Boeing and the FAA.

As professional pilots I would think you would be equally interested (for the sake of your own preservation) in holding the manufacturer that created this Rube-Goldberg piece of utter BS to account, certainly as much, if not more than you want to hold a deceased and clearly under-trained crew to account. And I cannot imagine a more powerful lobby or forum- the pilots who fly the planes themselves for sharing your views and insights into what happened and how utterly unnecessary both hull losses were.

We can go round and round picking apart the numerous ways both crews could have and should have done better. What I would rather see is a discussion on how the community is going to hold the feet of Boeing and the FAA to the fire- for real (even incremental) change going forward. All so that the next "MCAS" never even gets to the drawing board because the concept was shot down in flames earlier in the process due to the manufacturer's desire to build safe airplanes no matter the cost.

Warm regards,
dce

[gums]

Salute!

Thanks Wonk. Another realistic appraisal of a problem that should never have presented itself.

Gums sends...

[KRUSTY 34]

CNN response should have been - Then why have you grounded the 737 MAX?

And why is the 767 tanker MCAS so different to the MAX- anything to do with training required?

I’ve seen (and even experienced personally) similar instances where in the face of a failure of Corporate integrity, the Corporation’s attempted qualifying statements only serve to throw up even more questions, and contradictions. Often you will see an almost pathological resistance to “come clean” so to speak.

Now that the Mainstream media are scrutinizing this thing, hopefully there are some journalists left with the Moxy and intellect to see through the double talk, and hold those responsible to account.

[Dee Vee]

not sure if this has been mentioned before..

https://edition.cnn.com/2019/04/26/politics/faa-hotline-reports/


The FAA tells CNN it received the four hotline submissions on April 5, and it may be opening up an entirely new investigative angle into what went wrong in the crashes of two Boeing 737 Max commercial airliners -- Lion Air flight 620 in October and Ethiopian Air flight 302 in March.

Among the complaints is a previously unreported issue involving damage to the wiring of the angle of attack sensor by a foreign object, according to the source.

[Bend alot]

We can hope Krusty.

I would like to thank 737 Driver & meleagertoo for their detailed responses as to what they would have done and when on the MCAS events.

I appreciate the time and effort for those two posts.

They are similar but have vast differences - the most significant being the "hand over" to the FO.

But on comparison to what is publicly available there are a few follow up questions/ or statements I will make soon (24-36 hours) none of these will be intended to be critical of either of you or the fatal crews - so please do not take offence.

Also keep in mind English has never been my strong point.

Also the 4 "related" reported defects all state no fault! so nothing was ever logged as a fault on the on-board system or was there ever any rectification/s. Anyway to know the crews of these flights?

[Cows getting bigger]

CNN response should have been - Then why have you grounded the 737 MAX?

And why is the 767 tanker MCAS so different to the MAX- anything to do with training required?


Supplemental - would you have expected the pilots to 'deal with it' if you knew it ran away at 2.5 rather than 0.6 deg?

[Bend alot]

Supplemental - would you have expected the pilots to 'deal with it' if you knew it ran away at 2.5 rather than 0.6 deg?
Yes very good fact!

[GordonR_Cape]

737 Driver

What MCAS will then attempt to do is run the trim nose down for 9 continuous seconds and spin the trim wheel about 37 times. I’ve asked this before, and I’ll ask this again: Starting from a stabilized, in-trim platform, exactly how long should a qualified 737 type-certified Captain who is hand-flying the aircraft let the trim run in one direction before he/she does something about it?


A long time ago I asked a critical question, to which I did not get a satisfactory answer. Perhaps you can indulge me.

On the B737, the flight computers (and the FDR post-crash readout**) know exactly how much nose-down trim has been applied to the horizontal stabiliser, but the pilots do not.

The only way for them to determine this is to look at the sliding scale between the manual trim wheels, or count the number of rotations, or infer from the elevator feel forces.

Stabiliser trim position is not shown on any of the primary flight displays, and AFAIK is not part of any routine instrument scan.

It seems that pilots have to infer runaway trim, rather than a big flashing display that could easily warn them of that fact. How un-ergonomic is this setup, that the most powerful flight control, is the one they have least information about?

Edit: **In much of the post-crash discussion, the question is asked why did the pilots stop trimming nose-up? Those comments were based on the FDR readouts, while the pilots had to infer the position of the horizontal stabiliser trim, relative to column forces and elevator feel, etc.

Edit: Or to put it even more bluntly: The pilots had to make a life-or-death decision about when to hit the trim cutoff switches, when they did not know the actual position of the horizontal stabiliser. Much of the post-crash "hindsight" analysis is based on the FDR readouts, which contain information that the pilots flying the aircraft did not have access to!?

[CurtainTwitcher]

737 Driver



A long time ago I asked a critical question, to which I did not get a satisfactory answer. Perhaps you can indulge me.

On the B737, the flight computers (and the FDR post-crash readout) know exactly how much nose-down trim has been applied to the horizontal stabiliser, but the pilots do not.

The only way for them to determine this is to look at the sliding scale between the manual trim wheels, or count the number of rotations, or infer from the elevator feel forces.

Stabiliser trim position is not shown on any of tbe primary flight displays, and AFAIK is not part of any routine instrument scan.

It seems that pilots have to infer runaway trim, rather than a big flashing display that could easily warn them of that fact. How un-ergonomic is this setup, that the most powerful flight control, is the one they have least information about?
I don't think i've ever looked at the trim setting in flight whilst hand flying. Throw in the stick shaker and IAS disagree, it would probably the the last thing that would get my attention too. Even in a runaway trim, just trying to communicate to the person sitting beside me what I thought was going on and what I was going to do would be tough.

Remember the trim is there to reduce workload. The first lesson of flying is to trim trim trim. Smooth small pitch and thrust adjustments & keeping the aircraft in trim significantly frees up the mind to process other details. An out of trim aircraft consumes ALL your cognitive resources, the instant you take you eyes off the attitude the aircraft will move significantly away from where you want it. You have to start putting in large inputs and things feel very out of control. That is why trainees from the Airbus struggle initially, they have to consciously remember to trim, as the aircraft won't sit where they left it.

It would be an interesting experiment in the sim to do a difficult sequence without touching the trim at all from takeoff to landing. I suspect even flying a bog standard circuit would be a very challenging exercise with takeoff trim set, particularly if in the forward region for a F25 takeoff. Perhaps someone with a bit of spare time in the sim could try this and report.

[jimjim1]

Found them, thanks! The reports were misfiled with the 737NG's for some reason. They appear to be reporting the same anomaly. Report numbers are ACN 1597286 and ACN 159380 for anyone looking for them.

https://asrs.arc.nasa.gov/search/database.html

For example:

Choose 737 NG
then text search
(max OR max8) AND pitch

27 hits

I do not have the expertise to read them and reliably comment.

Also, 5 possibly relevant reports: (PDF is easy to search)
https://www.documentcloud.org/documents/5766398-ASRS-Reports-for-737-max8.html
https://assets.documentcloud.org/documents/5766398/ASRS-Reports-for-737-max8.pdf
Still available as of 28 April 2019

"Contributed by: Cary Aspinwall, The Dallas Morning News"
HTML has some summary material (metadata) not in the pdf.

ASRS Reports for 737 max8
- A 737 Max 8 captain noted problems on takeoff
- An unidentified captain says the Airworthiness Directive does not address the
problem in November 2018.
- An airline captain called the flight manual for the Boeing 737 Max 8 "inadequate and
almost criminally insufficient."
- A co-pilot reported an altitude deviation in November.
- Co-pilot said after engaging autopilot, aircraft pitched nose down.
- Co-pilot reported that aircraft pitched nose down on departure.
- A Boeing 737 Max 8 goes nose down suddenly during takeoff, pilot reports incident.

[groundbum]

I'm still trying to get my head around how a certification fail of how the yoke feels, somehow led to a bodged computer controlling flight surfaces? Why not introduce a feel system to the yoke to pass certification? Scary how it morphed from one thing to another without a blink.

I'd also love to hear the B engineers side of how MCAS was specced and built and whether they were put under pressure to "just do it". As somebody earlier said, where's the integrity gone?

G

[GordonR_Cape]

Also, 5 possibly relevant reports: (PDF is easy to search)
https://www.documentcloud.org/documents/5766398-ASRS-Reports-for-737-max8.html
https://assets.documentcloud.org/documents/5766398/ASRS-Reports-for-737-max8.pdf
Still available as of 28 April 2019

"Contributed by: Cary Aspinwall, The Dallas Morning News"
HTML has some summary material (metadata) not in the pdf.

ASRS Reports for 737 max8
- A 737 Max 8 captain noted problems on takeoff
- An unidentified captain says the Airworthiness Directive does not address the
problem in November 2018.
- An airline captain called the flight manual for the Boeing 737 Max 8 "inadequate and
almost criminally insufficient."
- A co-pilot reported an altitude deviation in November.
- Co-pilot said after engaging autopilot, aircraft pitched nose down.
- Co-pilot reported that aircraft pitched nose down on departure.
- A Boeing 737 Max 8 goes nose down suddenly during takeoff, pilot reports incident.

All of those reports are suggestive, but inconclusive, in the absence of detailed corroborating evidence such as FDR readouts. The most likely explanation that matches anything to do with MCAS, would a transient high AOA value, due to turbulence soon after takeoff, or some non-permanent mechanical or electrical glitch.

[bill fly]

I'm still trying to get my head around how a certification fail of how the yoke feels, somehow led to a bodged computer controlling flight surfaces? Why not introduce a feel system to the yoke to pass certification? Scary how it morphed from one thing to another without a blink.

I'd also love to hear the B engineers side of how MCAS was specced and built and whether they were put under pressure to "just do it". As somebody earlier said, where's the integrity gone?

G
Thank you Groundbum - exactly my view too. As to why it was done the roundabout route via Stab tinkering - this seems long to have been a "fix-all" at Boeing and it was probably the obvious adjustment to them.
And while on the subject - refering to AoA input - what could possible go wrong? a few posts back - well a lot more can go wrong with a rogue input to the stab - as documented over many pages here... than to a feel spring.
If false AoA info were to trigger a false spring resistance, the only result would be a one time hardening of pull input - one time - which could be trimmed out.

[737 Driver]

737 Driver
A long time ago I asked a critical question, to which I did not get a satisfactory answer. Perhaps you can indulge me.

On the B737, the flight computers (and the FDR post-crash readout**) know exactly how much nose-down trim has been applied to the horizontal stabiliser, but the pilots do not.


You can be forgiven your unfamiliarity with the 737 cockpit layout, so let me help here. There is a direct reading of the stab position right next to the trim wheel:


https://cimg9.ibsrv.net/gimg/pprune.org-vbulletin/448x601/trim_wheel_d0099ed5db5414de3f1a33d4c1eac6a9a32371fa.jpeg

This is the view from the First Officer side, but there is an identical trim wheel and index on the Captain's side. You can also see the stab trim cutout switches just aft of the trim index.

The stab trim setting is not in the pilot's forward scan, but it is fairly easy to check at a quick glance. The green band is the takeoff trim zone. Normal takeoff trim is usually between 4.5 to 6.0 units. From personal experience, having the trim lower than 4.0 units or greater than 7.0 units in flight is highly unusual. If you told me I had to operate a flight at one constant trim setting (assuming a normal C.G.), I would say somewhere around 5.0 units would work. We do have procedures for a jammed stabilizer, and any 737 pilot should have been exposed to this non-normal as part of their initial training.

That being said, except for your initial takeoff setting, you don't operate the trim by reference to the index. You operate by feel. If you are holding in any sustained control pressures around any axis (pitch, roll, yaw), you would normally trim away those pressures until the controls were neutral. I say "normally" because there are some flying techniques that involve leaving in some control pressures in certain situations, but that is beyond the scope of this discussion. So in reality, you could tape over the index, and as long as you trimmed out the control pressures, then maintaining aircraft control should pose no problem. Again, this is assuming that you do not have an aircraft that is loaded outside its C.G. envelope.

In terms of increased awareness of a runaway trim situation, I will say that I liked the approach used on the MD-80. There was a aural tone that sounded for every degree of stab movement. A continuous movement of the stab, would produce a steady series of tones. This tone was active with the autopilot on or off, and actually was most useful in a situation where the autopilot was engaged, but the speed was bleeding off (i.e. autothrottles inop or disengaged while autopilot was attempting to hold altitude). Now, before anyone thinks this is a surefire fix, I'll just make the observation that flight crews have, on multiple occasions, demonstrated the ability to not hear aural warnings as well (most notably, gear up landings).

If there is one point I would like to hammer home, it is this. A pilot's primary reference to the aircraft's trim state is through the feel of the controls. If the control pressures are heavy, then they are not trimmed for whatever maneuver is being performed. For an experienced pilot, trimming properly should reside somewhere near the unconscious level - I believe procedural memory is the proper term. Learning to trim correctly is one of those psychomotor skills that can only be developed by constant practice - like riding a bike, throwing a baseball, or learning to dance. If you are already under a heavy cognitive load, and you have to think about trimming to actually do it, then you are miles behind the aircraft.

[737 Driver]

All of those reports are suggestive, but inconclusive, in the absence of detailed corroborating evidence such as FDR readouts. The most likely explanation that matches anything to do with MCAS, would a transient high AOA value, due to turbulence soon after takeoff, or some non-permanent mechanical or electrical glitch.

Just an observation.... you need to filter out all the reports in which either the flaps are extended (takeoff to about 1000') or the autopilot was engaged. MCAS is inhibited by these conditions.

[DaveReidUK]

Just an observation.... you need to filter out all the reports in which either the flaps are extended (takeoff to about 1000') or the autopilot was engaged. MCAS is inhibited by these conditions.

Quite so.

And that leaves precisely zero events in ASRS where MCAS was a factor.

[737 Driver]

Specifically to your point about being a forum for professional pilots. You are completely correct. Professional pilots who fly airplanes made and certificated by large companies and in the US the FAA. If this isn't the place to opine about a substandard or frankly lethal product being provided to you on which you will earn your living I don't know what is.

Look, I agree with pretty much everything you say, up to the point where it was the crews' fault for what happened. They had no control over their training. They had no control over Boeing's clear abuse of the certification process, and they had no input on a system which (as I have described previously) would try to kill you if you didn't get the diagnosis right. And that's an important distinction. In an earlier reply you spoke of numerous failures that you experienced which were nearly catastrophic. IIRC you mentioned engine failures as an example of a potentially fatal event. The problem is twofold: First, you need engines to fly. Like, I mean, you can't live without them right?? And second: Yes, an engine failure can be (and many times is) fatal. But it doesn't have to be, and if you goof a little bit the outcome isn't a 100 percent fatal conclusion. Even if you goof a lot the outcome is frequently far less than fatal.

If an engine failure happens there are a gazillion possible outcomes, all of which rely on you, the pilot, to select and control the final result.

But with MCAS there are only two possible outcomes, one is you keep flying if you line up the dots within roughly a minute (40 seconds if you believe media reports) the other is you are d-e-d dead.

I know of no other binary system/operational outcome that aligns with this and I once again submit this to the community: Anyone got an equivalent they can share??

Here is another attempt to try to illustrate how unique this circumstance is, and how profound Boeing's errors were in bringing this airplane forward for commercial use. (And how culpable they are as a consequence)

Imagine if your airplane had a third, previously unneeded engine that contributed nothing to the performance, stability, safety or functionality of the aircraft. I'm even going to give us the benefit of the doubt and say you know this third engine exists. If engines 1 or 2 fail you just do everything like you always have. Pull out the proper checklist, do your memory items and find someplace to land. But if engine #3 fails, well then you have 30 seconds to a minute to identify the correct engine, diagnose it and shut it down using an exact mechanism that has zero tolerance for deviation. If you fail to do this exactly right your third engine explodes and rips off the tail in the process and you and your airplane are toast on a stick.

That's what I mean when I say MCAS will try to kill you (it will...) and that's why I believe this is a unique circumstance and finally: That's why I place the responsibility for the entirety of the outcome for both flights at the feet of Boeing and the FAA.

As professional pilots I would think you would be equally interested (for the sake of your own preservation) in holding the manufacturer that created this Rube-Goldberg piece of utter BS to account, certainly as much, if not more than you want to hold a deceased and clearly under-trained crew to account. And I cannot imagine a more powerful lobby or forum- the pilots who fly the planes themselves for sharing your views and insights into what happened and how utterly unnecessary both hull losses were.

We can go round and round picking apart the numerous ways both crews could have and should have done better. What I would rather see is a discussion on how the community is going to hold the feet of Boeing and the FAA to the fire- for real (even incremental) change going forward. All so that the next "MCAS" never even gets to the drawing board because the concept was shot down in flames earlier in the process due to the manufacturer's desire to build safe airplanes no matter the cost.

Warm regards,
dce

Wonkazoo,

I understand your position, and I fully support what you say about the need to hold the manufacturers, regulators and airlines accountable. However, I guess we will have to just agree to disagree on how much control the crews had on the outcome.

To me, the great tragedy of these two accidents is not in the complexity of the malfunction, but rather in the simplicity of the appropriate response.

Since my very first days as a student pilot, one primary commandment has been repeated over and over and over again. This commandment applied to all operations, normal and otherwise. Following this commandment may not always save the day, but disregarding it will almost always lose it.

So I'll say it again and again, for as long as it takes: FLY THE AIRCRAFT, first, last, and always.

For all situations, for all malfunctions, for all weather conditions, for all regimes of flight, some pilot must be actively monitoring, and if necessary, actively flying the aircraft. Whenever there is undesired or unexpected aircraft state, the pilot's first and most important priority is NOT to figure out what it is going wrong. The pilot's first priority is to FLY THE AIRCRAFT. Set appropriate attitude and power, monitor the performance, trim as necessary, adjust as appropriate.

In all of the discussion of these accidents, there has not been a single shred of evidence that the primary flight controls or trim were not responding to pilot inputs. There has been no credible argument that if the pilot flying had simply set a reasonable pitch attitude, set a reasonable power setting, and trimmed out the control pressures, that the plane would not have been flyable. The fact remains that in the heat of the moment, these crews forgot or disregarded the first commandment of aviation - FLY THE AIRCRAFT, first, last, and always. WHY they forgot and what corrective measures can be taken to train future crews should certainly be part of a serious post mortem, but we cannot remain in a state of denial regarding what happened.

Sadly, no matter how many times this commandment is repeated, and tacitly acknowledged by just about every pilot, we still seem to have difficulty applying it in practice. Any professional pilot here likely has access to various incident/accident reports. We can read the narratives and easily determine in which cases there was someone actively monitoring or flying the aircraft, and in which cases they were not. Fortunately, most of the "not's" do not wind up as a smoking hole somewhere, but it is still somewhat distressing how often the first commandment is forgotten.

FLY THE AIRCRAFT, FLY THE AIRCRAFT, FLY THE DAMN AIRCRAFT

[meleagertoo]

I'm still trying to get my head around how a certification fail of how the yoke feels, somehow led to a bodged computer controlling flight surfaces? Why not introduce a feel system to the yoke to pass certification? Scary how it morphed from one thing to another without a blink.

Please explain why the current solution should be seen as "bodged" when you already have a speed-trim system (isn't that an electronic 'bodge' too?) that this can ride off the back of, and why it would be 'better' (ie in your terminology somehow less bodged) to add a completely new artificial feel system - despite the fact that MCAS is just that anyway - artificial feel. On the KISS principle MCAS seems remarkably rational to me though as we now know with attendant and unforseen failure modes. I'm far from saying Boeing and the FAA (and by association every other authority that has the MAX on it's register) haven't made errors, but to suggest they are criminal, negligent, collusion or whatever is unfair and irrational without evidence that they are more than mere honest errors.

Despite ample - frankly overwhelming evidence to demonstrate the pilots were guilty of 'bodges' galore no one here is using that sorrt of loaded, accusative and frankly rather hysterical terminology against them, despite their many failures to act correctly being the ultimate causes of the accidents? Rather they are rationally and logically discussing pilots' 'errors' and 'omissions'. It seems only when Boeing and the FAA are involved this hysteria ramps up and wild, totally unsubstantiable accusations of bodgery, incompetence, colliusion, criminal negligence, lethal design etc get flung around when the worst we can see they did from the info we have avaiable is underestimate a consequence, albeit one that imo they quite correctly and reasonably took to be a given as the entire industry always has done from day one. That is; design aircraft to be safe in the hands of - in your terminology, any non 'bodging' crew to sort out using existing procedures? Boeing quite reasonably believed that a trim runaway brought about by MCAS would be seen for what it is - a trim runaway and dealt with accordingly. As, I submit, would 98% of commentators here had that proposition question been put to them before the accidents. I have no doubt they were as gobsmacked as the rest of us when that proved not to be the case. But then they didn't factor in what's beginning to look like sub-standard training and operating procesures and airlines that don't adhere to international standards of promulgating safety bulletins - and why should they have done?

It is abundantly clear that a lot of commentators here are neither pilots nor much related to the industry and clearly many are subject to a '100% of everything must always be 100% safe" delusion or of the muck-stirring 'always assume evil and corruption in business and politics' brigade but some of the shrill and baseless accusations made are nothing short of scurrilous, especially in view of the lack of evidence to support them. Despite the amount of unequivocal evidence of misdeeds by the pilots that could not unreasonaby be couched in that same shrill accusatory language they are notably much more understated and kept to facual levels as befits Professional Pilots discussing Professional matters. The input of conspiracy-theorey activists is most unwelcome and quite inappropriate in an accident investigation discussion, especially so when they continue to use inflammatory language and wild baseless accusations - it merely flags up their unpleasant agenda and irrational, random thought processes which advances our knowledge and understanding not one jot.

In other words, present evidence and discuss it rationally - please!
There are shades of grey, not everything is black or white.
Present, discuss, conclude, don't just shoot from the hip...

[HundredPercentPlease]

FLY THE AIRCRAFT, FLY THE AIRCRAFT, FLY THE DAMN AIRCRAFT

Your mic may be stuck.

Could you answer this? Why do you think "the flying of the aircraft" did not occur satisfactorily in the ET accident?

[20driver]

Your mic may be stuck.

Could you answer this? Why do you think "the flying of the aircraft" did not occur satisfactorily in the ET accident?

Because the airplane ended up in a smoking hole?

[GordonR_Cape]

meleagertoo
Please explain why the current solution should be seen as "bodged" when you already have a speed-trim system (isn't that an electronic 'bodge' too?) that this can ride off the back of, and why it would be 'better' (ie in your terminology somehow less bodged) to add a completely new artificial feel system - despite the fact that MCAS is just that anyway - artificial feel. On the KISS principle MCAS seems remarkably rational to me though as we now know with attendant and unforseen failure modes. I'm far from saying Boeing and the FAA (and by association every other authority that has the MAX on it's register) haven't made errors, but to suggest they are criminal, negligent, collusion or whatever is unfair and irrational without evidence that they are more than mere errors.

I am not a pilot, but from an engineering and computer programming viewpoint, the items listed by BluSdUp (edit: in the other thread) are exactly those I would be concerned about the in the revised MCAS implementation. See: https://www.pprune.org/rumours-news/618252-boeing-737-max-software-fixes-due-lion-air-crash-delayed-40.html#post10457935

Any flight control system that relies on an "unreliable" input (AOA disagree threshold of 5.5 degrees), and a 10 second delay lag in implementing nose-down trim, is asking for trouble.

They (collectively) have a much lower probability of killing anyone than the original MCAS, but IMO should never be present on an aircraft that relies on manual flight controls, where precise and direct authority is expected, and pilot/machine induced oscillations could be a killer.

P.S. I have already made the same point several times in this thread (as have some others), and am not going to repeat the whole argument.

[Zeffy]

https://www.wsj.com/articles/boeings-enduring-puzzle-why-certain-safety-features-on-737-max-jets-were-turned-off-11556456400

Boeing’s Enduring Puzzle: Why Certain Safety Features on 737 MAX Jets Were Turned Off

Some midlevel FAA officials contemplated, but then quickly dropped, idea of grounding Boeing 737 MAX jets last year

By Andy Pasztor
April 28, 2019 9:00 a.m. ET

Plane maker Boeing Co. didn’t tell Southwest Airlines Co. when the carrier began flying 737 MAX jets in 2017 that a standard safety feature, found on earlier models and designed to warn pilots about malfunctioning sensors, had been deactivated.

Federal Aviation Administration safety inspectors and supervisors responsible for monitoring Southwest, the largest MAX customer, were also unaware of the change, according to government and industry officials.

Boeing had turned off the alerts which, in previous versions of the 737, informed pilots if a sensor known as an “angle-of-attack vane” was transmitting errant data about the pitch of a plane’s nose. In the MAX, which featured a new automated stall-prevention system called MCAS, Boeing made those alerts optional; they would be operative only if carriers bought additional safety features.

Southwest’s cockpit crews and management didn’t know about the change for more than a year after the planes went into service. They and most other airlines operating the MAX globally learned about it only after the fatal Lion Air crash last year led to scrutiny of the plane’s revised design. The FAA office’s lack of knowledge about Boeing’s move hasn’t been previously reported.

“Southwest’s own manuals were wrong” about the status of the alerts, said Southwest pilots union president, Jon Weaks. Since Boeing hadn’t communicated the modification to the carrier, the manuals still reflected incorrect information.

Following the Lion Air crash, Southwest asked Boeing to reactivate the alerts on planes already in its fleet. This move, along with questions about why they had been turned off, prompted FAA inspectors overseeing Southwest to consider recommending that the airline’s MAX fleet be grounded while they assessed whether pilots needed additional training about the alerts. Those internal FAA discussions, however, were brief and didn’t go up the chain, according to documents reviewed by The Wall Street Journal.

Boeing hasn’t specifically addressed why it turned off the feature, called “AOA disagree alerts,” without informing customers. Questions surrounding that move have remained unanswered since October, when the Lion Air accident killed 189 people, followed by an Ethiopian Airlines crash in March of the same model that took 157 lives. MAX planes remain grounded. Boeing recently said it would book $1 billion in expenses tied to the groundings and related business disruptions.

In previous 737 models, the computer-generated alerts appear as colored lights in the cockpit when a plane’s twin angle-of-attack sensors provide significantly different data from each other. In the MAX, they serve the same purpose but additionally are intended to warn pilots that MCAS, the new automated system implicated in both accidents, could misfire because of faulty sensor data.

MCAS commands that automatically push down the nose of a plane can overpower a pilot’s efforts to get out of a dive. In the Ethiopian jet, which lacked the disagree alerts, it took four minutes for the pilots to realize that incorrect data was coming from one of the sensors, according to investigators’ preliminary report.

A Boeing spokesman said that from now on, “customers will have the AOA disagree alerts as standard” on all MAX aircraft, including those coming out of the factory and already delivered to airlines. Boeing is currently devising a new software package that aims to fix MCAS by making it less powerful, while also restoring the alerts. The moves are among the safeguards the plane maker and FAA have embraced to make MCAS less hazardous if it misfires, and to get the fleet back in the air.

A Southwest spokeswoman said that before the loss of Lion Air Flight 610, the carrier had assumed the alerts “as operable on all MAX aircraft.” Boeing “did not indicate an intentional deactivation,” she said. Today, the reinstated feature offers “an added cross-check on all MAX aircraft,” even though none are flying.

Although the alerts were reactivated, some midlevel FAA officials who oversaw Southwest briefly considered the possibility of grounding its fleet of roughly 30 of the 737 MAX aircraft until the agency established whether pilots needed to receive new training, according to documents reviewed by the Journal.

Less than a month after the Lion Air jet went down, one FAA official wrote that AOA-related issues on 737 MAX jetliners “may be masking a larger systems problem that could recreate a Lion Air-type scenario.”

Roughly two weeks later, other internal emails referred to a “hypothetical question” of restricting MAX operations with one message explicitly stating: “It would be irresponsible to have MAX aircraft operating with the AOA Disagree Warning system inoperative.” The same message alluded to the FAA’s power: “We need to discuss grounding [Southwest’s] MAX fleet until the AOA Warning System is fixed and pilots have been trained” on it and related displays.

The email discussions, previously unreported, were fleeting red flags raised by a small group of front-line FAA inspectors months before the Ethiopian jet nose-dived last month. The concerns raised by the FAA inspectors never progressed up the agency. Within days, they were dismissed by some involved in the discussions who concluded that the alerts provided supplemental pilot aids rather than primary safety information, and therefore no additional training was necessary. During that stretch and beyond, Boeing and the FAA continued to publicly vouch for the aircraft’s safety.

These very concerns, however—ranging from potential training lapses to confusion by many aviators about the specifics of angle-of-attack alerts—have now emerged as high-priority items as Boeing’s design decisions face scrutiny. The issues are among those being pursued by various congressional, criminal and Transportation Department investigators, say people with knowledge of their lines of inquiry.

On Wednesday, a Boeing spokesman said that while the internal FAA discussions were under way last year, “there was no data that indicated the fleet should be grounded.”

An FAA spokesman said the agency expects to mandate that all 737 MAX aircraft include working disagree alerts. But government and industry officials said questions about why the alerts were turned off in the first place remain central to uncovering the history and safety problems surrounding the MAX fleet.

Testifying before a Senate panel last month, acting FAA chief Daniel Elwell said one important factor is prioritizing data pilots receive. “Every piece of real estate in a cockpit is precious,” he said. “You put one gauge up there, you are sacrificing another.”


At American Airlines Group Inc., one of the few carriers that initially had working angle-of-attack alerts as part of a broader array of optional MAX safety features for which it paid extra, pilots are still anxious to see Boeing and the FAA get all the steps right to end the grounding.

In a meeting about a month after the first crash, a Boeing executive told American Airlines pilot union officials that American’s MAX cockpit warning lights would have helped them avoid problems like those encountered by the Lion Air pilots, union officials who attended the meeting said. A Boeing spokesman has previously said the executive didn’t recall making that statement.

“Our minds are not at ease on this,” said Dennis Tajer, the pilot union spokesman.

—Andrew Tangel, Robert Wall and Alison Sider contributed to this article.

Write to Andy Pasztor at [email protected]

[HundredPercentPlease]

Because the airplane ended up in a smoking hole?

No.

My question is: WHY did the "flying of the aircraft" not actually happen? Not "prove that it didn't happen".

The crew at some point did not keep the fundamental parameters in check. I'll give you some examples as to why this may happen:

Didn't know that you had to fly the DAMN aircraft (737 Driver style)
Misdiagnosis
Distraction - both pilots
Volume of failure information leading to cognitive overload
Conflicting information leading to cognitive overload
Insufficient training, resulting in difficulty diagnosing, leading to cognitive overload
Lack of systems knowledge, resulting in difficulty diagnosing, leading to cognitive overload
Multiple failures, some not able to be cancelled, resulting in cognitive overload.
etc (looking for 737 Drivers viewpoint)

If I asked WHY the crew just did not "fly the aircraft" in the Eastern 401 accident, everyone knows the answer. So WHY did it happen here?

[Water pilot]

Wonkazoo,
In all of the discussion of these accidents, there has not been a single shred of evidence that the primary flight controls or trim were not responding to pilot inputs. There has been no credible argument that if the pilot flying had simply set a reasonable pitch attitude, set a reasonable power setting, and trimmed out the control pressures, that the plane would not have been flyable. The fact remains that in the heat of the moment, these crews forgot or disregarded the first commandment of aviation - FLY THE AIRCRAFT, first, last, and always. WHY they forgot and what corrective measures can be taken to train future crews should certainly be part of a serious post mortem, but we cannot remain in a state of denial regarding what happened....

FLY THE AIRCRAFT, FLY THE AIRCRAFT, FLY THE DAMN AIRCRAFT

There is evidence from the voice recorder (of the second accident) that the co-pilot was unable to move the stabilizer. Now if you are convinced that the accident was the pilot's fault then you may disregard it as insufficient knowledge of how to move the backup manual wheel connected to a cable connected to the stabilizer (what year was this plane built, anyway?) but there it is. Now perhaps the definition of "primary flight control" does not include the stabilizer, but as a creature of the water rather than a dragon rider, I'd consider anything that has the ability to put the bow of the flying ship into the ground to be a "primary flight control".

Perhaps to bridge the gap between us engineer types and the dragon riders, I have a question. I have seen some very well thought out responses to the accident scenario. This is good, it helps safety to imagine what should have been done (even if it turns out not to be relevant young dragon riders can learn something more about their craft from reading it.) Now can somebody working out this scenario give me an estimate of how many feet of altitude they think that they would have lost in the accident scenario? And then, for us poor fish men down on the water, how much altitude can you afford to lose in the worst case scenario at the worst case airport? And then, how much altitude would they have lost when they were a young dragon rider and had just been qualified?

Murphy's law is actually a serious engineering proposition, not a cynical joke. Humans have a hard time understanding scale and probability. Our brains just can't comprehend tens of millions of flight hours a year, so when we judge the probability of "x AND y" happening we tend to vastly understimate the probablity of "x AND y" EVER happening. Science shows us that the new plane has a fatal flaw, it nearly killed one set of pilots and did actually kill two other sets of pilots. Was it a coincidence that it happened on a new instance of a new model of plane? Statistics can be used to model this, but intuition says that in this social media age, we would know if it was a fairly common occurence for airplanes to suddenly pitch down at takeoff. Heck, we get front page CNN coverage when there is an emergency landing because of a little bit of smoke in an aircraft cabin, and even the best dragon riders probably would have to admit that in the MCAS scenario the pasengers might have felt a bit of discomfort.

A large number of ship accidents are caused by not knowing where you are. A friend tells me that one of his captains had a habit of walking up to the most junior officer and asking "where are we, mister?" Damn good advice, and we could say that every time somebody hits (charted) rocks it was their fault and what they really needed was a guy behind them saying "WHERE ARE WE, MISTER?" Or, after a few ships have hit the rocks and caused massive oil spills, we could put a lighted bouy on the rocks to warn them.

[meleagertoo]

meleagertoo

Any flight control system that relies on an "unreliable" input (AOA disagree threshold of 5.5 degrees), and a 10 second delay lag in implementing nose-down trim, is asking for trouble.

They (collectively) have a much lower probability of killing anyone than the original MCAS, but IMO should never be present on an aircraft that relies on manual flight controls, where precise and direct authority is expected, and pilot/machine induced oscillations could be a killer.


Perhaps you'd add your aviation-based criticism of the Speed Trim system, the Elevator Feel system, and the Rudder pressure limiting system to name just three - that already exist, unremarked, on this manual flight control aircraft?

And explain why/how it is unacceptable to have safety augmentation devices in a manual control aeroplane yet you appear to believe it is perfectly OK for an entire aeroplane's control systems to be electronic? That doesn't seem rational.

How does the mechanical method of controlling the aeroplane ('manual' cable controls or fly-by-wire) have any bearing on the matter?

[boofhead]

Almost every accident is caused by or contributed to by pilot error. This accident is no different. Apart from the failure to pull the throttles back, which alone would have caused the airplane to be lost due to the excess speed, the pilot could have followed the checklist for the trim failure. He did not, or did not do it as per the checklist. The loss of the aircraft was not due to the failure of the MCAS, it was due to the failure of the crew to follow the correct emergency checklist procedures. It matters not what caused the trim to run away; in this case it was the MCAS but next time it could be a stuck trim switch, or a broken wire: are we supposed to accept that it is OK for a professional pilot to simply fly the aircraft into the ground because he was unaware of the cause of the runaway trim?

I cannot follow the logic that because Boeing did not give enough information on the MCAS to the crews (who obviously would not have understood it anyway) it is OK for a pilot to kill everyone on board his aircraft. There is no excuse for not knowing how to fly your aircraft, especially when the procedure that would have allowed the crew to safely land was in the QRH and undoubtedly had been trained, was ignored or not followed.

And more so in this case, when the Lion Air guys had already demonstrated the wrong way to handle this emergency.

Don't gang up on Boeing, sure they could have handled the introduction of the MCAS on the 737 better, but it is patently obvious that if they had done a better job, this crew would not have understood or changed anything in the way they flew and would have flown into the ground anyway. Or are we all lawyers now, going after the deep pockets? If so, how are we as pilots or the airlines or customers supposed to benefit? If we don't face up to the fact that pilots are not being trained properly and fix that, this type of accident will continue to happen.

[GordonR_Cape]

Perhaps you'd add your aviation-based criticism of the Speed Trim system, the Elevator Feel system, and the Rudder pressure limiting system to name just three - that already exist, unremarked, on this manual flight control aircraft?

And explain why/how it is unacceptable to have safety augmentation devices in a manual control aeroplane yet you appear to believe it is perfectly OK for an entire aeroplane's control systems to be electronic? That doesn't seem rational.

How does the mechanical method of controlling the aeroplane ('manual' cable controls or fly-by-wire) have any bearing on the matter?

The systems you mention were all well documented, and have been proven and tested over decades of use. I don't think the same applies to MCAS (yet), and to describe it as a "safety" system is laughable.

My concern is not about whether MCAS is manual or electronic, nor whether the flight controls are manual or not. My concern is the introduction a system with a known delay lag. And secondly one which relies on a pair of AOA sensors, with a known inability to produce consistent and reliable readings.

[meleagertoo]

Melleagertoo

you do see the contradiction in these two statements of yours don't you? If not, just to clarify - where is the LEGAL evidence behind you allegations as opposed to the kangaroo court of your "professional" colleagues who wish to act as judge and jury on the basis of a very preliminary report?


No, of course I don't.

Who ramped this up to "LEGAL", this isn't a court of law. Or are you changing the rules midstream?

No kangaroo court - back to hysterical overstatement again! The evidence for pilot's actions? The preliminary reports and the data traces are all we have to go on but they're enough to tell a great deal. Or do you hold them discredited due to some hitherto unsuggested collusion or corruption?

I'm surprised you even need to ask that question...
There is evidence from the voice recorder (of the second accident) that the co-pilot was unable to move the stabilizer.

Until we hear the unredacted CVR I think we should be a bit circumspect about what was actually said or meant. Do we even know that he was talking about the stab(control column) itself or the trim system, and if so whether the electric or manual one? I'm not sure we do. Do we know if the pilots were talking in English or Amharic? There may well be translation interpretations in there or the chap's English might not have been quite up to saying exactly what he meant. There's probably precious little to choose between "pitch jam", "it won't move on the cc trim switches", "It isn't moving, shouldnt it be?" or "I can't make it trim" but I didn't get the handle out might all be possible yet quite different interpretations of the words we've been given.
The complete CVR recording (better in the raw but accredited in translation if necessary) will tell us a great deal more I expect.

[meleagertoo]

The systems you mention were all well documented, and have been proven and tested over decades of use. I don't think the same applies to MCAS (yet), and to describe it as a "safety" system is laughable.

My concern is not about whether MCAS is manual or electronic, nor whether the flight controls are manual or not. My concern is the introduction a system with a known delay lag. And secondly one which relies on a pair of
The systems you mention were all well documented, and have been proven and tested over decades of use. I don't think the same applies to MCAS (yet), and to describe it as a "safety" system is laughable.

My concern is not about whether MCAS is manual or electronic, nor whether the flight controls are manual or not. My concern is the introduction a system with a known delay lag. And secondly one which relies on a pair of AOA sensors, with a known inability to produce consistent and reliable readings.


They weren't well documented once upon a time. They started out as new systems once, you appear to be saying its bad just because it is new. I don't follow that 'logic' because there is none.

You stated you distrusted the use of augmentation systems on mechanically controlled aircraft so clearly you thought the control operating method central to your argument. Now you've changed your mind?

Speed trim system operates on a known delay lag. What's so awful about a known delay lag? Pilots operate on a known delay lag...

How/why is MCAS not a safety system - what is stall awareness/avoidance if not safety? And why laughable? Here goes the baseless hyperbole again.

AOA sensors suffer from a known inability to produce consistent and reliable readings do they? This is news to the industry which has been using them for decades. AOA sensors cannot produce consistent readings?????? Do you want to re-consider that extraordinary statement? I sure hope so, but the substance of your post entire is nonetheless reduced to about zero, line by line.

I shudder to think of what it is you engineer with logic and rationale of that standard!

[Water pilot]

Testifying before a Senate panel last month, acting FAA chief Daniel Elwell said one important factor is prioritizing data pilots receive. “Every piece of real estate in a cockpit is precious,” he said. “You put one gauge up there, you are sacrificing another.”
Again, what year is this? The MAX has computer display screens. Is a pop-up message a novel concept to the airline industry?

The one thing I learned in my career was how to recognize management/government BS, and this is not even good BS. The quality of BS produced by Amercians has declined markedly over the years. They need to bring back us old guys who really know how to do it.

[737 Driver]

There is evidence from the voice recorder (of the second accident) that the co-pilot was unable to move the stabilizer. Now if you are convinced that the accident was the pilot's fault then you may disregard it as insufficient knowledge of how to move the backup manual wheel connected to a cable connected to the stabilizer (what year was this plane built, anyway?) but there it is. Now perhaps the definition of "primary flight control" does not include the stabilizer, but as a creature of the water rather than a dragon rider, I'd consider anything that has the ability to put the bow of the flying ship into the ground to be a "primary flight control".

You are confusing cause and effect here. It is entirely possible to fly any aircraft into a zone where some of the controls are ineffective or unresponsive (for example, a full stall). Yes, if you let the 737 (or a number of other Boeing's for that matter) get into a severe out-of-trim situation, the manual trim wheel may be difficult, if not impossible, to use without some special techniques previously discussed.

There is no evidence from the DFDR that the manual electric trim was inoperable. That is, every time the pilot made a stab trim input with the yoke switch, the stab moved as expected. The accident aircraft arrived at a severe out-of-trim state because the flying pilot did not use a sufficient amount of electric trim. When the electric trim was then cutout in this state, the manual trim was effectively unavailable.

[gearlever]

When I started flying jets (B727) one training captain covered the scale of the trim wheel with his right hand during various phases of flight and asked me about the appropriate setting.

Try it.....

[Mac the Knife]

Something potentially fatal happened at the end of a procedure in the theatre next to mine last Thursday.
Nothing unforeseeable, more in the nature of losing an engine at V2, which you chaps endlessly train for.
Much fright, alarms going off and folks running around looking worried (as well they might).
By chance I was walking by, knew exactly what to do and did it. All ended well and the kid was fine.

All I can say is never underestimate the startle factor. 50 seconds is a very short time indeed
for those unfortunate pilots to have worked out what was happening and taken remedial action.

Only my grey hairs and 20,000 hours avoided a possibly fatal mishap.
There is no substitute for having experienced and dealt with the real thing.

Old Mac

[737 Driver]

Your mic may be stuck.

I will keep repeating the first commandment of aviation - FLY THE AIRCRAFT, first, last, and always - as long as there is a single aviator out there who denies that this was not the crew's primary responsibility and does not make a credible argument that the tools to do so were unavailable to them.

​​​​​​If I asked WHY the crew just did not "fly the aircraft" in the Eastern 401 accident, everyone knows the answer. So WHY did it happen here?

And this is precisely the direction that I believe the conversation should go.

I find several things unacceptable about these accidents (your list may be different):

1. It is unacceptable that Boeing designed MCAS in such a way that it produced such a hazardous failure mode,
2. It is unacceptable that the FAA and various certification authorities delegated so much of the oversight,
3. It is unacceptable that the airlines, in conjunction with Boeing and the certificate authorities, were too focused on minimizing the training rather than maximizing the safe introduction of the MAX, and
4. It is unacceptable that the flight crews, given everything we know about the malfunction, were ultimately unable to FLY THEIR AIRCRAFT into a stabilized state and land safely.

Now, of these four items, which one does the professional pilot corps have the most power to address?

Rightly done, the goal of a post mortem into the crew response is not an exercise in assigning blame. It is an exercise in determining what went wrong and what can be done so that future crews do not meet such an ill-fated end.

Germane inquiries would look at the background and experience of the crews, training policies and standards, hiring standards, and corporate policies and culture. While it may be a delicate subject, the individual backgrounds of the accident pilots should be looked at to see if they had any history indicating problems with airmanship skills or discipline.

We can also hold up a mirror and look at our own experiences. Have we become too complacent? After all, aviation is very, very safe. Most of the time, the manufactures get it right, the regulators get it right, the dispatchers get it right, the weather forecasters get it right, the maintenance folks get it right, Air Traffic Control gets it right, and the trainers get it right. Most of the time. Checking, re-checking and employing a high degree of vigilance is a lot of work. Turning off the magic and hand-flying is work. Insisting on a high standard for yourself and your flying partner is work.

Engaging the automation and letting HAL do all the work is seductive. How many of us know someone who bids the easy wide-body flying because they want to sit back, chill and not really fly? How many of us spend most of our sim prep time trying to learn the script (and the answers) rather than digging into some aspect of our aircraft or operation that we've become a bit rusty on? How many of us spend more effort on planning our layovers than planning our flights? Are we becoming handmaidens to some future accident/incident that should have seen coming?

I've been guilty of all these sins and more at one time or another. Fortunately, some external event will usually come along and remind me of my obligations. The MAX/MCAS debacle has been one of those events.

I don't think anyone of us ever wants to see another accident like Lion Air or Ethiopian. So yes, Boeing needs to build better aircraft, the certificate authorities needs to exercise better oversight, and the airlines need to stop trying to get by with minimum training at a minimum cost. And we need to do everything in our power to become better aviators.

[HundredPercentPlease]

I think I agree with nearly all of that.

However... why (do you think) on this occasion, were the ET crew unable to continue stabilised flight? You have stated that it is unacceptable (which is obvious)... but why couldn't they? Nice simple question!

Also, as an aside:

It is unacceptable that the flight crews, given everything we know about the malfunction

You have to consider what they knew.

[gums]

Salute!

Thanks, 737, a great list

I find several things unacceptable about these accidents (your list may be different):

1. It is unacceptable that Boeing designed MCAS in such a way that it produced such a hazardous failure mode.
2. It is unacceptable that the FAA and various certification authorities delegated so much of the oversight.
3. It is unacceptable that the airlines, in conjunction with Boeing and the certificate authorities, were too focused on minimizing the training rather than maximizing the safe introduction of the MAX.
4. It is unacceptable that the flight crews, given everything we know about the malfunction, were ultimately unable to FLY THEIR AIRCRAFT into a stabilized state and land safely.


And then
of these four items, which one does the professional pilot corps have the most power to address?

As Richard Bach posted long ago in "Flying" or maybe the EAA magazine, all crashes are "loss of control".
- pilot/crew is negligent - CFIT, poor pre-flight and elevator locks are not removed, etc
- pilot/crew is completely unprepared for even the smallest problem - incompetent
- pilot/crew performs incorrect procedure for an emergency, e.g.shuts down the wrong engine ( one good thing for we single-seat, single engine types)
- mechanical/computer failures that cannot be overcome by pilot/crew, e.g. Wonk's problem 20 years ago,
- catastrophic failure of major parts of the plane, e.g. TWA800, terrorist bomb, SAM over Crimea

737 is correct: This is the best forum to deal with the rhetorical question - Pprune aircrew. And although I am inactive, I had a super career as a "professional pilot" and faced/overcame more than a few hairy episodes. Only came close to the nylon letdown two or three times. I didn't fly passengers or have a crewmember except for VIP joy rides in the family model and a few hundred hours in an interceptor early on.

So imagine, if you will........How many successful resolutions to problems or prevention of same have resulted from a pilot peeking at these forums between flights? Huh?

Gums sends...

[MurphyWasRight]

...
That being said, except for your initial takeoff setting, you don't operate the trim by reference to the index. You operate by feel. If you are holding in any sustained control pressures around any axis (pitch, roll, yaw), you would normally trim away those pressures until the controls were neutral. I say "normally" because there are some flying techniques that involve leaving in some control pressures in certain situations, but that is beyond the scope of this discussion. So in reality, you could tape over the index, and as long as you trimmed out the control pressures, then maintaining aircraft control should pose no problem. Again, this is assuming that you do not have an aircraft that is loaded outside its C.G. envelope.
...
.
Thanks for confirming my impression that the crew would not be referencing the absolute trim numbers.
One puzzling feature of the ET (and to some extent LionAir) traces is the failure to fully trim after MCAS inputs.

I wonder if part of this could be due to a 'muscle memory" illusion that after having to pull with a lot of force to counteract the ND trim the relaxed force after the partial re-trim felt less out of trim than actual situation.

The report does not have a collum force trace, just position. Can anyone hazard a guess as to what force might have been required.

[Cows getting bigger]

I find the following text very interesting, a safety report written in Nov 18 by a captain who cleary was on his game and wary of a potential MCAS trap:

It was day three of six for me and day three with very good FO (First Officer). Well rested, great rapport and above average Crew coordination. Knew we had a MAX. It was my leg, normal Ops Brief, plus I briefed our concerns with the MAX issues, bulletin, MCAS, stab trim cutout response etc. I mentioned I would engage autopilot sooner than usual (I generally hand fly to at least above 10,000 ft.) to remove the possible MCAS threat.

So, he had the post-Lion Air FCOM and had clearly thought about it. His solution was to minimise exposure to MCAS territory in order to reduce risk. Great airmanship but not exactly the answer to the problem.

[737 Driver]

However... why (do you think) on this occasion, were the ET crew unable to continue stabilised flight? You have stated that it is unacceptable (which is obvious)... but why couldn't they? Nice simple question!

Also, as an aside:

You have to consider what they knew.

As long as we agree this is speculation, based on the limited evidence presented in the accident report, I'll be happy too.

First, let's look at the First Officer. He had 361 hours total, and 207 hour in the 737 of all types. Most notable, those 207 hours had all occurred in the previous 90 days. He had 56 hours in the MAX. I do not know how much switching around between the MAX and the NG he did, so it is not possible to say from the data provided how much recent currency he had in the MAX. Taken as a whole, you have a pilot who was given about 150 hours of total time before he was put into commercial airliner, and he had been on the job for about three months prior to the accident. This simply boggles my mind that this is even possible. The First Officer could have been the best stick alive, but there simply is no substitute for experience, both in time and years, particular as it relates to aircraft emergencies. As a result, the Captain was handicapped from the start. When things start going south, and the pilot flying has his hands full of airplane, having an experience and trusty partner who can feed you information, prompt you on actions, and help you maintain situational awareness is worth its weight in gold. This wasn't exactly a single-pilot operation, but it was pretty close.

Looking at the Captain's background (and I'll say right here some of this is second hand), it appears he went from the Ethiopian Training Academy into the right seat of the wide-body pretty quickly. His 737 time as an FO is not split out, but doing some triangulating it appears that much of his 8122 hours was gained as a wide-body First Officer. As you probably know, lots of wide-body time does not necessarily translate into lots of flying in critical phases, and even less with the automation turned off. Looking to the Captain's immediate attempts to engage the automation when it was inappropriate to do so combined with some poor aircraft handling skills points to a case of significant automation dependency. Forced to hand-fly an aircraft when he was uncomfortable with doing so and facing a significant distraction in the form of the stick shaker, he appears to have fallen back on default behaviors like trying to fly a "normal" takeoff profile (A/P @ 400', climb to 1000', retract the flaps) when it was not appropriate (particularly retracting the flaps given what was known about MCAS). The aircraft was never really stabilized when MCAS kicked in, and by that time it appears the Captain had achieved cognitive overload making the remainder of his attempts to control the situation ineffectual. I think the FO did the best that he could, but I really don't know how assertive a three-month 360 hour First Officer could be in this situation.

To go deeper into the question of WHY this crew was so unprepared would require additional specifics regarding the training environment, airline policies and procedures (particularly in regards to the use of automation), and crew management issues that I do not currently possess. Maybe some others can chime in here.

Again, this is just speculation. I'm sure the accident investigators will be looking into all of these issues and will hopefully shed some light in subsequent installments on their findings.

[Smythe]

You can be forgiven your unfamiliarity with the 737 cockpit layout, so let me help here. There is a direct reading of the stab position right next to the trim wheel:


https://cimg9.ibsrv.net/gimg/pprune.org-vbulletin/448x601/trim_wheel_d0099ed5db5414de3f1a33d4c1eac6a9a32371fa.jpeg

This is the view from the First Officer side, but there is an identical trim wheel and index on the Captain's side. You can also see the stab trim cutout switches just aft of the trim index.

.



737 driver, looking at the TO greenband, on the 738, (and all other NG that I can remember)it is 1.5 to 6.5, while on the MAX it is 3 to 8...this is a significant difference. Thoughts?

[formulaben]

There is evidence from the voice recorder (of the second accident) that the co-pilot was unable to move the stabilizer.

...still not clear that was the case as meleagertoo alluded to earlier, but even if so this is with the other pilot hauling back on the yoke with airspeed well above Vmo. Not exactly within the realm of normal certified operation.

Anyone else here have an instructor that would demand you "let go of the controls" when it was obvious you were using the elevator instead of trimming out to maintain a flightpath?

[wonkazoo]

I will keep repeating the first commandment of aviation - FLY THE AIRCRAFT, first, last, and always - as long as there is a single aviator out there who denies that this was not the crew's primary responsibility and does not make a credible argument that the tools to do so were unavailable to them.

And this is precisely the direction that I believe the conversation should go.

I think in the attempt to be artful the other night one of the main reasons I wrote what I wrote wasn't communicated clearly enough. (I am referring to my post about bailing out of the Goshawk in 1996...) It occurs to me now that in that failure lies a lot of the disconnect between me and 737 Driver on this one issue, and many others as well.

What I was trying to convey that night was the complete and total disconnect that happens when a very real, very lethal emergency is presented to someone who just seconds before was sitting comfortably doing the same thing they had done hundreds or thousands of times before with predictable outcomes every time. So for those who fall back on the tried and true mantra of FTFA (I'm from New York, you can't say anything without at least one eff being in there...) to fault the crews I hope you can begin to understand that in order to FTFA you have to have a functioning intellect able to process complex and copious inputs and in the short time that each crew had they almost certainly never got past the startle-factor and confusion (I hate to use this word, but let's say paralysis) that the events inflicted on them.

For those of you who think you are super-human and will never flinch when the bullet heads your way I am here to tell you that you will, and the only thing that will determine whether or not you survive is partly luck and partly how quickly you are able to return to a quasi-functional state- if in fact you are able to do so before the clock runs out on your life experiences. 40 seconds (as reported by media) is a stupidly short period of time to be startled, shocked, scared, and thence to recover and take decisive action. I would argue it is a nearly impossible window to react effectively.

Perhaps the most frustrating thing for professional pilots (because it implies that you are not in fact in control of your entire domain...) is that you cannot train this away, you cannot tell which pilots will be totally paralyzed and incapacitated vs. those who will shrug and go on piloting vs. those who will recover quickly and get about their business. I smile when I read the pilots who write here in obscene terms about how the crews should have done this and that (specifically not referring to 737D here) because I know full well, and from experience, that they are as likely as anyone to be incapacitated if one day things really do go far south.

If your hands are shaking so hard you can barely hold on to something like a yoke from all the adrenaline pumping through your system FTFA becomes not a mantra but an unattainable goal. THAT'S WHY THEY CRASHED. THEY RAN OUT OF TIME BEFORE THEIR BRAINS COULD NORMALIZE TO THE POINT THAT THEY COULD FTFA.

One more quickie- to 737 Driver's point about no control failures- I would argue that a horizontal stab that cannot be moved due to overpowering control forces (while still in the envelope BTW) is a totally incapacitating failure and will be a significant part of the finding on why ET crashed. In other words: It was far from a perfectly flyable airplane. The crew did what they were supposed to do- they stopped MCAS from trimming down any longer. But they could not rewind the trim to an operable setting.

Warm regards,
dce

[MurphyWasRight]

Forced to hand-fly an aircraft when he was uncomfortable with doing so and facing a significant distraction in the form of the stick shaker, he appears to have fallen back on default behaviors like trying to fly a "normal" takeoff profile (A/P @ 400', climb to 1000', retract the flaps) when it was not appropriate (particularly retracting the flaps given what was known about MCAS). The aircraft was never really stabilized when MCAS kicked in, and by that time it appears the Captain had achieved cognitive overload making the remainder of his attempts to control the situation ineffectual. I think the FO did the best that he could, but I really don't know how assertive a three-month 360 hour First Officer could be in this situation.
.
The report does state that the FO called trim runaway so he was not totally inert.
There is a saying in medicine that rare conditions are most likely to be diagnosed by bright interns or very experienced doctors. The intern does not have the experience to reject improble diagnoses while the very experienced are more likely to pick up on the "something does not fit" observations. From your description one would have to say the Captain was in the moderately (at best) experienced category.

The other possible trap is that the since Captain was able to engage the autopilot before he selected flaps up he may have thought things were better than they were, false stick shaker only moderate airspeed disagree.
Does anyone know the likely reading of the backup (uncorrected for AoA) air speed indicator in these conditions?

[HundredPercentPlease]

Thank you for having a stab at answering.

retract the flaps) when it was not appropriate (particularly retracting the flaps given what was known about MCAS).

How did he know he was going to have an MCAS event? He was dealing with a stall warner that shouldn't have been warning.

I would advocate asking "why" to every conclusion. And writing "because..."

There are two lines of thinking here: it was a poor aircraft and they were poor pilots. Let me explore both, using the "why" system:
1. The aircraft had hidden killer behaviour because it was a financial requirement to have a common TR because the regulator allowed this because the regulator is weak.
2. The crew performed poorly because they were inadequately trained because it was a common TR which was allowed because the regulator is weak.

If we boil this down, it doesn't really matter whether you subscribe to pilot error or Boeing error or both. Ultimately this has arisen through inadequate regulation. The regulator should have stepped in with the whole instability issue, the MCAS fix, the lack of documentation and the lack of training.

This month it's the FAA, but it so easily could have been any other national authority. The industry is in a mess due to inadequate regulation - and it's Boeing, the airlines, the pilots and the passengers are suffering.

I would avoid making assumptions about the skills of the crews. In Europe it's easy to do too - we hear incompetent sounding fat cigar chewing fools who don't know that you can have a flight level of 90, but we try to remember that judging ability by nationality or assumed education is very, very wrong.