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Ethiopian airliner down in Africa

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Ethiopian airliner down in Africa

Old 29th Apr 2019, 07:10
  #4561 (permalink)  
 
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Originally Posted by formulaben View Post
but I still believe that advanced airmanship (e.g. ATP level) should have prevented a complete loss.
I wouldnt really like to make a judgement on that before the final report comes out, but it is of course a possibility.
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Old 29th Apr 2019, 07:21
  #4562 (permalink)  
 
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Originally Posted by formulaben View Post
I agree. And if I wasn't clear previously, Boeing clearly screwed the pooch, but I still believe that advanced airmanship (e.g. ATP level) should have prevented a complete loss.
The question has to be the following. From 1000 randomly selected 737 crews, how many stuff it into the ground. Mind we are starting from 2 out of 3.
Had the planes been NGs with the same failure, AOA failed high on PF side on rotation), how many would have stuffed it into the ground? (I hope the answer is 0.)
Is the increase in this number acceptable and why was it allowed to increase?
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Old 29th Apr 2019, 09:43
  #4563 (permalink)  
 
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Originally Posted by 737 Driver View Post
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
737 driver
you are saying what Iíve said since the beginning. Someone just said we need a plane that donít go wrong. Dream on.
This ref QF72 is interesting. 65 complex faults. ALL aural warnings going off at once. Crippled (clearly not) aircraft.
Safe landing. FLY THE PLANE. PITCH POWER. TREAT WARNINGS WITH CAUTION IF THEY DONT APPEAR VALID Use excellent training and CRM to overcome the unexpected.
on takeoff with correct pitch/power/rate of climb/ groundspeed you are safe even if every aural and visual computer generated warning is sounding simultaneously. Youíve got to be trained to cope with that.
AF477 wasnít. Many more. My concern is not the avionics although clearly MCAS Needs a Mk2 version without the glitches we know about. It is that we may have literally thousands of younger pilots already out there and in the pipeline untrained for the totally unexpected.
https://www.abc.net.au/radio/program...pigny/10337426
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Old 29th Apr 2019, 09:56
  #4564 (permalink)  
 
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Originally Posted by Cows getting bigger View Post
The pilot bit is only one element of the issue. Whichever way you look at this, MCAS was a fix to a problem generated by the manufacturer trying to squeeze the last drop out of an airframe designed before I was born. The fix was, at best, a second rate solution which transferred an additional element of hazard management to the pilots; the expectation was that pilots would be good enough to handle the event. Shuffling risk down the line - hmmmm.

An uninformed question (sorry, only 36 years and 22,000 non-Boeing hrs) - how often has the 737 flavour of aircraft had a trim runaway event, how is it manifested (other warnings/cautions) and at what rate does the trim runaway?
Just my wild speculation, but there are several orders of risk:
1. How many times has runaway trim actually pushed a B737 into the ground? Zero.
2. Electromechanical switches are the most likely component to get stuck in the on position. Given that there are two adjacent thumb switches on the B737, and both have to be active, this seems like an extremely low flight risk.
3. Autopilot software malfunction? Turn off autopilot.
4. Electrical wiring and other faults? Unknown.
5. MCAS? 2 out of 3.
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Old 29th Apr 2019, 10:46
  #4565 (permalink)  
 
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If

If the Lion Air crew and the Ethiopean crew had saved their days as recommended, would MCAS still be flying now?
If so, would that be a happy state?
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Old 29th Apr 2019, 10:51
  #4566 (permalink)  
 
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CowsShuffling risk down the line -’
Cows, Gordon,
Conventional risk is judged on past outcome, probability vs severity.
‘Future’ risk (certification) has to be judged on the likely-hood of a failure (system safety analysis). If trim can runaway however unlikely, then experts judge of the severity of outcome - manufacturer and certification.

Historically, the mitigation for trim runaway in the 737 appears to have been based on pilot recognition and intervention - inhibit then use manual wheel trim, thus reducing the outcome severity (ex 707 procedure?)
It also appears that the possibility extreme out of trim conditions was recognised, where the tail forces exceed those which allow manual trim. Thus there was an additional procedure requiring large, high stick force elevator inputs to raise the nose, then releasing the elevator input (adverse load), thence the reduced tail load enables manual trim. (To what extent was this flight tested)

The assumptions and procedure appear to have been carried forward for later 737 variants; assuming that certification validated these against aircraft aerodynamic and engine changes (and smaller trim wheel - NG).
This process appears to have further extrapolated for the MAX, but again the extent of certification checks on the effect of (significant) changes is not known.

The outcome of recent accidents suggest that the assumptions relating to large out of trim conditions in the MAX are inappropriate - recognition and intervention (were these aspects considered, checked, or flight tested in the MAX).
Thus the risk associated with trim runway in the MAX appear to be significantly higher that originally judged.
Reviewing the MAX trim system might conclude that runaway is an unacceptable failure mode where recover depends on human intervention; these aspects are independent of MCAS malfunction or modification.
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Old 29th Apr 2019, 11:20
  #4567 (permalink)  
 
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Originally Posted by L39 Guy View Post
Wonkazoo,

737 Driver is doing an exceptional job of articulating what a lot of us professional pilots both on this forum and elsewhere think about this whole MAX affair: MCAS needs to be tweaked (although fundamentally there is nothing wrong with a single sensor device that prevents a stall but intervening in the flight controls like numerous other aircraft)
Rubbish. I have 21 years in safety related systems including design and certification and you NEVER, NEVER use a single fallible input to drive a safety critical system. And then to give it full authority driving a critical control surface, allowing it to trim full down? Breathtaking incompetence. Also, you ALWAYS design to fail-safe. This doesn't mean what most people think. It doesn't mean it will never fail. It means it will fail in a safe state. AOA disagree is an absolute obvious failure and yet MCAS failed in the most unsafe state that it could possibly have.

A 16 year old electronics student with a week's training in safety related systems design would have done a better job.

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Old 29th Apr 2019, 11:45
  #4568 (permalink)  
 
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Originally Posted by L39 Guy View Post
these accidents scream "pilot error" for not fulfilling their role as the last line of defense in the Swiss Cheese model.
Just like a goalkeeper who dives the wrong way during a penalty shoot out. Last line of defence and he failed. Clearly should have trained better.

Any pilot who looks at the FDR tapes in detail and doesn't get a shiver going down their spine, and a feeling in the back of their mind "yep, on a bad day, that could have been me" is either genuinely a superhero or has an overestimation of their own abilities. Which is just as dangerous as low abilities.
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Old 29th Apr 2019, 12:10
  #4569 (permalink)  
 
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Pilots - last line of defence and Swiss Cheese.

L39 et al, I’m a couple of hours/years short of your experience but my personal experience is that we are not an exceptional line of defence; there are a number of holes in our particular slice of cheese. So, whilst I get paid to be the goalkeeper, there is huge amounts of evidence to prove that I will never keep a clean sheet.

Yep, Lion Air guys could have gotten lucky, and the Ethiopian guys may have done better. But by introducing a half-baked solution like MCAS, Boeing made a pretty shocking back-pass to the goalkeeper. Personally, I’ll be quite happy if in my remaining 10 years or so, all I ever have to do is encourage the defence and mid-field such that I never have to make another save.

Dare I say it, but the differences between A & B philosophy really show here. In the early days of A, I was like many pilots - dubious and wary of automation. Over a generation of flying later we seem to have got our head around they fact that HAL(A) has matured, is now rather good at his job and, generally speaking, our side of the house only gets into trouble when we ignore HAL(A). Meanwhile, HAL(B) appears to still be at school and capable of having hissy-fits, just like my teenage daughter.

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Old 29th Apr 2019, 12:17
  #4570 (permalink)  
 
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If...

Originally Posted by jan99 View Post
If the Lion Air crew and the Ethiopean crew had saved their days as recommended, would MCAS still be flying now?
If so, would that be a happy state?
Yes.
No.

From the response of all involved, the system "requires" at least one crash to get substantive action. In this case, it took 2.

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Old 29th Apr 2019, 12:46
  #4571 (permalink)  
 
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Originally Posted by 20driver View Post
Because the airplane ended up in a smoking hole?
Based on everything I’ve read, I would say that these pilots were frantically trying to fly their aircraft, but MCAS had other ideas!
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Old 29th Apr 2019, 13:29
  #4572 (permalink)  
 
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Coverage released on Apr 16th:

On Apr 11th 2019 The Aviation Herald received a full copy of the Flight Operations Manual (FOM), Revision 18B released on Nov 30th 2018, which is currently being used by Ethiopian Airlines (verified in April 2019 to be current). Although Boeing had issued an operator's bulletin on Nov 6th 2018, which was put into Emergency Airworthiness Directive 2018-23-51 dated Nov 7th 2018 requiring the stab trim runaway procedure to be incorporated into the FOM ahead of the sign off of this version of the FOM (the entire document is on file but not available for publishing), there is no trace of such an addition in the entire 699 pages of the FOM.

...
...
It turned out, that only very cursory knowledge about the stab trim runaway procedure exists amongst the flight crew of Ethiopian Airlines even 5 months after the EAD was distributed.
...
...
Leaving aside for now the vexed question of Boeing's engineering solutions, something few of us as pilots are really well versed in, it seems to me that the crux of the Ethiopian accident is going to centre on the chilling lines in bold above.

The Indonesian accident was in a way more understandable because of the startle factor despite the unbelieveable precursors to it on previous flights and the standards involved there (which are a completely seperate can of worms) but they should have caused global awareness of the problem very quickly. And did. Mostly.

Focus on operating procedures at Bishoftu will eventually coalesce arond the matters highlited above (if indeed they prove true) but Avherald has a pretty good reputation for sound info.
As I've asked before how can it be possible for two professional pilots on a type with a known and highly public failure mode to appear not to be aware of it's symptoms when it occurs to them? Are these guys hermits with no exposure to global media, internet or crewroom discussions? What the heck else was their 737 crewroom discussing in the months after LionAir? It doesn't seem possible pilots could be so out of such an important and contemporary loop. Or does Ethiopian really exist virtually isolated in a world of it's own?

Worse - the failure of the airline to publish Boeing's amendments and advice. That is a FUBAR of truly epic proportions - unless that sort of thing isn't regarded locally as a FUBAR, but just the way Ethiopian does things...

Worse still, if true, the apparent lack of awareness appears not restricted to the accident crew alone but is shared by many of their colleagues. Is this a cultural thing perhaps?

What this all seems to boil down to is chronic and unrecognisably bad procedures in Ops standards in not one but two airlines. The Human Factors people are going to have a field day over these 'cultural' issues here - be they company or national, which is increasingly looking like one of, if not the major player in both accidents.
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Old 29th Apr 2019, 15:19
  #4573 (permalink)  
 
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.

Okay, a lot of ink got spilt yesterday, and I'll also offer my apologies to anyone offended by my admittedly passionate approach. But is has been passion with a purpose. In the interest of moving the conversation along, I would like to more explicitly address a subject that I've only touched on so far.

There are those among us who believe that, when presented with sufficient novelty and distraction, it is completely understandable for an aviator to misdiagnosis a problem and not apply the proper corrective action. After all, we are only human, and all humans are fallible. I really don't have a problem with this general concept, but I strongly disagree that it is a problem beyond remediation.

Let me start with an observation. When the stick shaker went off, the Ethiopian Captain did not turn into a formless lump of clay. He actually did fly the aircraft after a fashion. He manipulated certain controls and he provided directions to the First Officer. I think it is worth looking carefully at what he actually did - rotate, climb to 400', engage the autopilot, continue climb to 1000', retract the flaps, contact ATC, request a vector. If I presented this sequence of actions to you without any preamble as to place or time or aircraft condition, what does this look like? If you said a normal takeoff profile, go to the head of the class. I humbly submit that, when all was going to shit and the Captain was uncertain as to what was going on, he defaulted to his training. Unfortunately, he defaulted to the wrong training.

Let's consider for a moment aircraft reject procedures. Everything is fine up to V1, continue the takeoff. Certain things happen prior to V1, not only reject the takeoff, but reject the takeoff with a set of aircraft-specific actions that must be accomplished in a timely manner. Please read that sentence again. There are at least two "default modes" of operation present in any takeoff (more if you wish to count emergency specific actions like Engine Failure). Which default mode the pilot selects makes all the difference in the outcome.

Just as the "continue the takeoff" mode would be inappropriate with an Engine Fire light prior to V1, the "reject the takeoff" mode would be inappropriate with a Master Caution/Anti-ice light once above 80 KIAS (at least it would be on the 737). For a pilot transitioning from single-engine to multi-engine operations, this is a whole new realm of experience that does not come naturally. (Those of you who have screwed this up in the sim, please raise your hands. ) The key to successfully training for this maneuver depends on repetitive practice (procedural memory) with a particular focus on the appropriate triggers.

What I am suggesting is that one of the ways out of the conundrum presented by the Ethiopian and Lion Air accidents is to first acknowledge that there really was a "default mode", a set of aircraft-specific set of actions that if accomplished in a timely manner, would have changed the outcome. Please read that sentence again. The default mode to which I refer is the simply the one that I have been repeating ad nauseam: Turn off the magic, set the pitch, set the power, monitor the performance, trim the aircraft, move to a safe altitude.

Perhaps some of our gentle readers are starting to clue in why I keep repeating this phrase. It is because when you go to bed at night, I want you to be thinking the words, "Turn off the magic, set the pitch, set the power, monitor the performance, trim the aircraft, move to a safe altitude." I want you to be thinking about these words when you get up in the morning, when you have a cup of coffee, when you are taking a dump, when you are driving your automobile. I want you to think about these words when you are in the sim or when you are "chair flying" a scenario. I want these words to become your mantra. Most importantly, I want you to be thinking these words for every takeoff, every landing, and truly, for every flight operation. Turn off the magic, set the pitch, set the power, monitor the performance, trim the aircraft, move to a safe altitude. Repetition, repetition, repetition.

Once we've committed these actions to procedural memory, then all we need to do is work out the trigger. We have triggers for rejects, we have triggers for engine failures, we have triggers for emergency descents, we have triggers for all sorts of emergencies. When that trigger presents itself, then a certain set of default actions follow.

Let me suggest an appropriate trigger here. When presented with an unexpected warning, an undesired aircraft state, or a loss of situational awareness and you are unclear as to what you should do next: Turn off the magic, set the pitch, set the power, monitor the performance, trim the aircraft, move to a safe altitude.

Keep repeating this set of actions until you arrive at a stabilized condition where you can better assess what is going on. This procedure is basically the Swiss Army Knife of our non-normals. When you have no clue as to what to do next, Turn off the magic, set the pitch, set the power, monitor the performance, trim the aircraft, move to a safe altitude. Given what we know of Ethiopian 302, Lion Air 610, Air France 447, and a host of other aircraft accidents, I think it is reasonable to say if the crews had applied this procedure, then there would be a few hundred more people alive today.

Easy to say, hard to do you might respond. Yes, you're right. Hard to do, but not impossible to do.

There was a time in my aviation career when one would be subjected to the whims of a sadistic simulator instructor whose only job was to present you with a host of malfunctions and upsets for which there was only one correct initial response: Turn off the magic, set the pitch, set the power, monitor the performance, trim the aircraft, move to a safe altitude. You did this again and again and again until it was impressed upon you that there will come a time when you really have no clue what is going on and that the only safe harbor was, Turn off the magic, set the pitch, set the power, monitor the performance, trim the aircraft, move to a safe altitude. After some passage of time without sufficient evidence that this was a "cost-effective" use of sim time, this type of relatively unstructured training was replaced with what has largely become a set of scripts consisting of known problems and known answers.

I am suggesting that in the aftermath of these accidents there should be a strong reemphasis at every level of training and operations that, despite all efforts to the contrary, the professional pilot can still be faced with novel and potentially hazardous circumstances that exceed all malfunction-specific training. In those circumstances, when there is no other obvious solution, Turn off the magic, set the pitch, set the power, monitor the performance, trim the aircraft, move to a safe altitude.

Specifically, our training needs to intentionally incorporate surprise, uncertainty, and ambiguity because that is one of the hazards we are likely to face. Some of us have had the opportunity to train in an altitude chamber where we learned first-hand our hypoxia symptoms so that we could better respond to those symptoms in a timely manner. In the same vein, what is needed is a type of training that repetitively introduces us to our startle reflex so we can better recognize it and respond appropriately. And what is that appropriate response? In the absence of any other clear guidance, Turn off the magic, set the pitch, set the power, monitor the performance, trim the aircraft, move to a safe altitude. I humbly submit if that if the Ethiopian and Lion Air crews had been offered this type of training, then we would not be having this conversation today.

I fully realize that some of us are at airlines that are not going to take this message to heart and will not substantially change their training regimen. In those cases, it falls to the individual pilot to do whatever he can to train himself. Repeat the mantra, chair fly some scenarios, and know that at some future point, you may be presented with the unknown and have no clue what to do. In those cases,Turn off the magic, set the pitch, set the power, monitor the performance, trim the aircraft, move to a safe altitude. This will not fix every possible set of malfunctions, and there will be situations which are truly unrecoverable. Fate is Still the Hunter, but I am hoping we may have learned a thing or two since Ernie Gann penned those words. You can only do what you can do with what you have. However, as long as you have an aircraft that is flyable, you will rarely be wrong if you:
.
Turn off the magic, set the pitch, set the power, monitor the performance, trim the aircraft, move to a safe altitude.

Last edited by 737 Driver; 29th Apr 2019 at 18:59.
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Old 29th Apr 2019, 15:25
  #4574 (permalink)  
 
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Originally Posted by Droop Snoot View Post
Yes.
No.

From the response of all involved, the system "requires" at least one crash to get substantive action. In this case, it took 2.
In which case the exact quality of maintenance and training at the specific airlines is of limited relevance to the greater scheme.
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Old 29th Apr 2019, 15:34
  #4575 (permalink)  
 
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On Apr 11th 2019 The Aviation Herald received a full copy of the Flight Operations Manual (FOM), Revision 18B released on Nov 30th 2018, which is currently being used by Ethiopian Airlines (verified in April 2019 to be current). Although Boeing had issued an operator's bulletin on Nov 6th 2018, which was put into Emergency Airworthiness Directive 2018-23-51 dated Nov 7th 2018 requiring the stab trim runaway procedure to be incorporated into the FOM ahead of the sign off of this version of the FOM (the entire document is on file but not available for publishing), there is no trace of such an addition in the entire 699 pages of the FOM.
Boeing's Emergency AD says nothing of the sort.

It's not up to Boeing what an airline does or doesn't put in its FOM - the AD refers instead to the Airplane Flight Manual (AFM), where Boeing does have the ability to require changes as the AFM forms part of the aircraft certification.

One might have hoped that Avherald would understand the difference between the two publications.
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Old 29th Apr 2019, 15:35
  #4576 (permalink)  
 
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Not sure where you are getting those numbers as they don't match what's in my FCOM.
Not about inflight feel, was simply looking at the TO range shown. The range difference says alot about CG.
When it comes down to it, is the average TO set the same on the 738 and 737-800?

Last edited by Smythe; 29th Apr 2019 at 17:05.
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Old 29th Apr 2019, 15:45
  #4577 (permalink)  
 
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Originally Posted by Smythe View Post
Was simply looking at the TO range shown. When it comes down to it, is the TO set the same on the 738 and 737-800?
Looking at the illustrations (again, no specific numbers provided), they appear slightly different but not so much that I would be concerned about it. With the new engines, one should expect a difference. The 737 is not the first, nor will be the last, airframe that has been re-engined, and changes to accommodate the new powerplants are inevitable. As long as one keeps the aircraft within its authorized c.g. limits, then there really isn't a problem.
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Old 29th Apr 2019, 15:53
  #4578 (permalink)  
 
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Boeing Didnít Advise Airlines
Boeing Co. didnít tell Southwest Airlines Co. and other carriers when they began flying its 737 MAX jets that a safety feature found on earlier models that warns pilots about malfunctioning sensors had been deactivated, according to government and industry officials.
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Old 29th Apr 2019, 16:18
  #4579 (permalink)  
 
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Originally Posted by PerPurumTonantes View Post
Rubbish. I have 21 years in safety related systems including design and certification and you NEVER, NEVER use a single fallible input to drive a safety critical system. And then to give it full authority driving a critical control surface, allowing it to trim full down? Breathtaking incompetence. Also, you ALWAYS design to fail-safe. This doesn't mean what most people think. It doesn't mean it will never fail. It means it will fail in a safe state. AOA disagree is an absolute obvious failure and yet MCAS failed in the most unsafe state that it could possibly have.

A 16 year old electronics student with a week's training in safety related systems design would have done a better job.
Newsflash: the entire stabilizer trim system in the B737 is a single point of failure system - there is only one electric motor, there is only one screw jack and any of these can (and have failed) and that is why there is and has been for the past 50 years a Stab Trim Runaway checklist that disables this single point of failure system and the pilot intervenes and trims the aircraft manually. And, a stab trim runaway Aircraft Nose Down (AND) exhibits the same characteristics as an MCAS failure and send the aircraft hurtling toward terra firma; a stab trim runaway Aircraft Nose Up (ANU) will send an aircraft towards the heavens and a stall combined with gravity will quickly bring it back to terra firma.

There are numerous other systems in aircraft which are single point of failure which require pilot intervention: engine failures, for whatever reason, are one. Pressurization where the motors controlling the outflow valves can fail and human intervention is required, hydraulic systems where if the main system fails certain services are not available (Centre system in the large Boeings as an example).

I can go on and on with other examples of systems in aircraft which are not a "single fallible input to drive a safety critical system". In some cases like an engine failure, there is no possible solution to get around this due to physics so that is why we have trained, professional pilots flying airliners and why there is a separate endorsement to fly multi-engine aircraft. We do not live in a utopian world in aviation so we manage it by education and training.
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Old 29th Apr 2019, 16:21
  #4580 (permalink)  
 
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Originally Posted by DaveReidUK View Post
Boeing's Emergency AD says nothing of the sort.

It's not up to Boeing what an airline does or doesn't put in its FOM - the AD refers instead to the Airplane Flight Manual (AFM), where Boeing does have the ability to require changes as the AFM forms part of the aircraft certification.

One might have hoped that Avherald would understand the difference between the two publications.
In any case it does seem the pilots were not as informed as they should have been.

It turned out, that only very cursory knowledge about the stab trim runaway procedure exists amongst the flight crew of Ethiopian Airlines even 5 months after the EAD was distributed. In particular, none of the conditions suggesting an MCAS related stab trim runaway was known with any degree of certainty. In that context the recommendation by the accident flight's first officer to use the TRIM CUTOUT switches suggests, that he was partially aware of the contents of the EAD and reproduced some but not all of the provisions and not all of the procedure, which may or may not explain some of the obvious omissions in following the procedure in full
The entire article is well worth reading also has thoughts on ability to manual trim etc

Crash: Ethiopian B38M near Bishoftu on Mar 10th 2019, impacted terrain after departure
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