Boeing Resisted Pilots Calls for Steps On MAX
I believe the notion that an AOA Disagree alert would have helped pilots deal with the accident scenarios is not valid. Pilots were unaware of the MCAS, therefore unaware of what causes it to trigger, or even that it had triggered. Making such a cognitive connection between AoA and the failure mode is highly unlikely.
I also believe that the notion of solving the problem with a software fix does not pass muster. The consequences of this failure mode are clearly catastrophic, and requires the type design to make its occurance extremely improbable. Of course using a single AoA sensor as input is insufficient because the probability of malfunction is on the order of 10E-5. Even using two sensors is hardly sufficient and could software fill the gap? Hardly. Considering that such a failure was not foreseen for the initial MAX certification, I wonder if it’s design assurance level is better than B, when it really needs to be A. If not, a lot more than coding changes is needed to make it so.
I also believe that the notion of solving the problem with a software fix does not pass muster. The consequences of this failure mode are clearly catastrophic, and requires the type design to make its occurance extremely improbable. Of course using a single AoA sensor as input is insufficient because the probability of malfunction is on the order of 10E-5. Even using two sensors is hardly sufficient and could software fill the gap? Hardly. Considering that such a failure was not foreseen for the initial MAX certification, I wonder if it’s design assurance level is better than B, when it really needs to be A. If not, a lot more than coding changes is needed to make it so.
Boeing have been using a simulator (at least one) and also have done over 200 flights and more than 360 hours on those flights to test MCAS.
If you have the simulator and you are doing a software fix, that is a lot of flying to confirm the fix.
B787 certification took 1,700 flights and almost 5,000 hours for a complete new type, not a sub system that was already certified.
If you have the simulator and you are doing a software fix, that is a lot of flying to confirm the fix.
B787 certification took 1,700 flights and almost 5,000 hours for a complete new type, not a sub system that was already certified.
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The following questions appear to be unanswered, by Boeing or anyone else.
1. Where did giving MCAS authority for such a large tailplane deflection come from? Flight test? The WSJ article hints at no. Wind tunnel data? If so, reducing the MCAS authority doesn't change the underlying data of why MCAS was allowed to do what it has been doing. How can we trust the "fix" if we don't know how the pre-fix condition came to be?
2. Why is such a simple yet important sensor as the AoA failing at such a high rate? Even without the MCAS, the AoA failure activates the stick shaker, not a simple "buzz" simulating buffeting but a rattle like a hardware store paint sticker -- a serious crew distraction. For all of the talk about AoA disagree lights being optional and the need for 3 AoAs, shouldn't the failure of even a single AoA be exceedingly rare? Are people seriously thinking of bird-strike damage? Is there lax quality control as suggested by the Air Force rejecting delivery of Boeing tankers? Some defect in the wiring?
1. Where did giving MCAS authority for such a large tailplane deflection come from? Flight test? The WSJ article hints at no. Wind tunnel data? If so, reducing the MCAS authority doesn't change the underlying data of why MCAS was allowed to do what it has been doing. How can we trust the "fix" if we don't know how the pre-fix condition came to be?
2. Why is such a simple yet important sensor as the AoA failing at such a high rate? Even without the MCAS, the AoA failure activates the stick shaker, not a simple "buzz" simulating buffeting but a rattle like a hardware store paint sticker -- a serious crew distraction. For all of the talk about AoA disagree lights being optional and the need for 3 AoAs, shouldn't the failure of even a single AoA be exceedingly rare? Are people seriously thinking of bird-strike damage? Is there lax quality control as suggested by the Air Force rejecting delivery of Boeing tankers? Some defect in the wiring?
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If I'm not mistaken, even the update to the Stab Trim Runaway wasn't the best example of communication. The last version just suppressed a word (the "continous" was cut off), the whole document didn't put any emphasis on it. Anyone reading it would have to compare with previous version, see that a word was supressed, would have to think "Humm, seems that it doesn't need to be continous anymore". And when the beast showed off slightly above ground, the last crew was expected to think "This shaking is active, it says I'm stalling, yes, surely this is related to the removal of the 'continous' from that checklist, let's do that!".
All threads were closed regarding "lack of new information, let's wait for substatial news". All threads hit a dead end with pages and pages of discussion on it was just necessary to "fly the aircraft", as if nothing else should be learned on why any crew would be doing something while heading to the ground that isn't trying to fly the aircraft...
If these details from newspapers aren't "news", I don't know what else would be. If all those details aren't enough to be considered on why the plane acted in unexpected ways for 3/3 crews, and just 1 one them could survive (and logged the problem with words clearly stating that they didn't consider to be MCAS problem... perhaps because MACS wa unknown until them)... if these details don't impact, at least, on how a crew should proced to recover from the problem... I don't know what else should be discussed.
Anyway, be it a big problem with many factors or be it just a matter that pilots should have done better, I don't think public is reliefed knowing that "you, travelling worldwide, do you know that certified pilots don't know how to deal with an easy problem that they just need to keep flying the plane?".
All threads were closed regarding "lack of new information, let's wait for substatial news". All threads hit a dead end with pages and pages of discussion on it was just necessary to "fly the aircraft", as if nothing else should be learned on why any crew would be doing something while heading to the ground that isn't trying to fly the aircraft...
If these details from newspapers aren't "news", I don't know what else would be. If all those details aren't enough to be considered on why the plane acted in unexpected ways for 3/3 crews, and just 1 one them could survive (and logged the problem with words clearly stating that they didn't consider to be MCAS problem... perhaps because MACS wa unknown until them)... if these details don't impact, at least, on how a crew should proced to recover from the problem... I don't know what else should be discussed.
Anyway, be it a big problem with many factors or be it just a matter that pilots should have done better, I don't think public is reliefed knowing that "you, travelling worldwide, do you know that certified pilots don't know how to deal with an easy problem that they just need to keep flying the plane?".
I have flown classic, NG & MAX over the last 14 years and have never experienced a stab runaway other than in the sim and my expectation would be that it was running continuously, we are aware of the STS trimming the aircraft as it accelerates or decelerates, so I wouldn’t initially at least have given a second thought to the first inputs by the MCAS and with most being new on type would probably put any difference down to the type.
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I believe the notion that an AOA Disagree alert would have helped pilots deal with the accident scenarios is not valid. Pilots were unaware of the MCAS, therefore unaware of what causes it to trigger, or even that it had triggered. Making such a cognitive connection between AoA and the failure mode is highly unlikely.
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I say hopefully since I am not impressed with troubleshooting flow that "followed the steps" but did not actually identify a root cause.
Psychophysiological entity
The Lion Air crew that flew the same airplane the day prior to the accident also encountered the MCAS-induced antistall system, and simply disengaged the system and completed the flight.
The software changes that are now being implemented by Boeing eliminate the need for the crew to recognize and correctly respond to a failure of an angle-of-attack sensor. This is done in recognition that there are airline pilots that are not capable of recognizing and mitigating certain system failures. It is a shame that it took two accidents with many fatalities to understand this, but it is not fair or reasonable to assert that Boeing and the FAA should have known the exact point when systems would become too complex for certain pilots. That said, Boeing was remiss in disabling the AOA “Disagree” message, which would have given pilots a clear prompt to override a system failure. Yet given that the trim wheel was spinning madly and the stick shaker was activated, it is doubtful that a small, yellow advisory message would have made a difference.
Roger H. Hoh
Society of Experimental Test Pilots Grass Valley, Calif.
The software changes that are now being implemented by Boeing eliminate the need for the crew to recognize and correctly respond to a failure of an angle-of-attack sensor. This is done in recognition that there are airline pilots that are not capable of recognizing and mitigating certain system failures. It is a shame that it took two accidents with many fatalities to understand this, but it is not fair or reasonable to assert that Boeing and the FAA should have known the exact point when systems would become too complex for certain pilots. That said, Boeing was remiss in disabling the AOA “Disagree” message, which would have given pilots a clear prompt to override a system failure. Yet given that the trim wheel was spinning madly and the stick shaker was activated, it is doubtful that a small, yellow advisory message would have made a difference.
Roger H. Hoh
Society of Experimental Test Pilots Grass Valley, Calif.
This would be laughable if it wasn't so damned offensive. Possibly the first time since joining PPRuNe in the early 2000's that something has made my blood boil.
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I believe the notion that an AOA Disagree alert would have helped pilots deal with the accident scenarios is not valid. Pilots were unaware of the MCAS, therefore unaware of what causes it to trigger, or even that it had triggered. Making such a cognitive connection between AoA and the failure mode is highly unlikely.
I also believe that the notion of solving the problem with a software fix does not pass muster. The consequences of this failure mode are clearly catastrophic, and requires the type design to make its occurance extremely improbable. Of course using a single AoA sensor as input is insufficient because the probability of malfunction is on the order of 10E-5. Even using two sensors is hardly sufficient and could software fill the gap? Hardly. Considering that such a failure was not foreseen for the initial MAX certification, I wonder if it’s design assurance level is better than B, when it really needs to be A. If not, a lot more than coding changes is needed to make it so.
I also believe that the notion of solving the problem with a software fix does not pass muster. The consequences of this failure mode are clearly catastrophic, and requires the type design to make its occurance extremely improbable. Of course using a single AoA sensor as input is insufficient because the probability of malfunction is on the order of 10E-5. Even using two sensors is hardly sufficient and could software fill the gap? Hardly. Considering that such a failure was not foreseen for the initial MAX certification, I wonder if it’s design assurance level is better than B, when it really needs to be A. If not, a lot more than coding changes is needed to make it so.
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Well I have both the current NG & MAX QRH in front of me and both state “continuously” and that is at the root cause here.
I have flown classic, NG & MAX over the last 14 years and have never experienced a stab runaway other than in the sim and my expectation would be that it was running continuously, we are aware of the STS trimming the aircraft as it accelerates or decelerates, so I wouldn’t initially at least have given a second thought to the first inputs by the MCAS and with most being new on type would probably put any difference down to the type.
In other words do you only respond to aircraft faults if you have NNC for them? Is this your company trained approach to problems - ignore them unless there's an NNC which fits precisely?
https://www.wsj.com/articles/flight-...b1d10cb08f8eca
OPINION | LETTERS
Flight Systems Have Become Too Complicated
There are airline pilots that are not capable of recognizing and mitigating certain system failures.
May 15, 2019 401 p.m. ET
Regarding Holman W. Jenkins, Jr.’s column “GM and Boeing Show How Safety Miscues Happen” (Business World, May 11): Most media reports portray Boeing as incompetent and inappropriately close with the Federal Aviation Administration. As Mr. Jenkins notes, any attempt by Boeing to defend its design is met with derision and contempt. This exaggerated portrayal increases the risk that the public will never recognize the real problem: Many current airline pilots are simply not up to the standard necessary to operate current systems. With that in mind, the airline industry—not just Boeing—needs to lower expectations related to pilot competency in designing systems and dealing with failures.
OPINION | LETTERS
Flight Systems Have Become Too Complicated
There are airline pilots that are not capable of recognizing and mitigating certain system failures.
May 15, 2019 401 p.m. ET
Regarding Holman W. Jenkins, Jr.’s column “GM and Boeing Show How Safety Miscues Happen” (Business World, May 11): Most media reports portray Boeing as incompetent and inappropriately close with the Federal Aviation Administration. As Mr. Jenkins notes, any attempt by Boeing to defend its design is met with derision and contempt. This exaggerated portrayal increases the risk that the public will never recognize the real problem: Many current airline pilots are simply not up to the standard necessary to operate current systems. With that in mind, the airline industry—not just Boeing—needs to lower expectations related to pilot competency in designing systems and dealing with failures.
The problem is going cheap and lazy on training, training, training. These are not complicated systems for the average airline pilot of average ability but with some experience and some keeness to comprehend and handle.
You just have to tell people how the airplane works and what the controls and indicators do. Boeing's stated assumption that the "runaway atabilizer drill" would cover the MCAS failure is completely off base and out of touch with pilots. Tell them how it all works and they will learn; don't assume knowledge that isn't covered in the manuals and NNC's.
We don't have to know enough to build it, we have to know enough to operate it, especially when it isn't working. Remember: one Lion Air guy did get it, got the crew to use the stab cut-out switches and he saved the airplane and all on board. Damned if he didn't tell the next crew though...It's a community of sharing, just like here.
In my view, after eight full aircraft courses in thirty-five years and hundreds of simulator sessions in Douglas, Boeing, Lockheed and Airbus types I know it takes some hard work, some memory work, some background, some experience and time in the books with regular recurrent work on one's own time thrown in. That's one's job as an airline pilot and that's one's profession - just like doctors, engineers, lawyers keep current, keep up and keep informed as best as one can.
Systems are too complicated? Nonsense. Sounds like the, "...too many notes" comment in a movie about Mozart.
Just because it uses both doesn't mean it is a hardware fix. Both AOA signals were going into the flight computer already, it just was looking at one at a time, taking turns per flight. Now it takes both simultaneously, compares them against each other and disables MCAS if the disagree is too big. All software AFAICT.
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I am a little confused. If you find that the trim is regularly winding nose down then stopping then more nose down then stopping - do you check that no NNCs apply (Runaway Trim says _continuous_ and what is happening is _repeated_ see the thesaurus) so just let it continue until you and PM are both pulling hard with feet on the instrument panel. Or do you like the captain of the penultimate Lion Air Flight trim back repeatedly and when it seems that there is a trim problem switch off stab trim (even if prompted from the jump seat)? Indeed even the final Lion AIr flight the captain was doing the same it was only when control was handed to the first officer that control column trim was not used to return the aircraft to trimmed flight.
Y
In other words do you only respond to aircraft faults if you have NNC for them? Is this your company trained approach to problems - ignore them unless there's an NNC which fits precisely?
Y
In other words do you only respond to aircraft faults if you have NNC for them? Is this your company trained approach to problems - ignore them unless there's an NNC which fits precisely?
“ my wife nags me continuously “. She presumably stops to draw breath? But it’s still continuous. Indeed continuous enough to kill you if you don’t stop it. It goes beyond the language in NNC though. You have to have systems knowledge to know that a STAB trimming forward ND over and over is continuous enough to kill you. It’s extremely basic knowledge. And you can’t let it get away from you. So you counter trim nose up continuously until back to neutral trim and switches off. That’s it. Now that the poor guys flying these two didn’t know this maybe, is a training issue.vlearly the one that got away did know. From the 707
to the 737-800 NG we were all taught that stab trim is a killer.
Quick glance.
This notion of needing to be an Oxford scholar of English semantic grammar is absurd. Continuously means “it keeps doing it. “ Whether it stops for a second and then does it again - it’s still continuous.
“ my wife nags me continuously “. She presumably stops to draw breath? But it’s still continuous. Indeed continuous enough to kill you if you don’t stop it. It goes beyond the language in NNC though. You have to have systems knowledge to know that a STAB trimming forward ND over and over is continuous enough to kill you. It’s extremely basic knowledge. And you can’t let it get away from you. So you counter trim nose up continuously until back to neutral trim and switches off. That’s it. Now that the poor guys flying these two didn’t know this maybe, is a training issue.vlearly the one that got away did know. From the 707
to the 737-800 NG we were all taught that stab trim is a killer.
Systems are too complicated? Nonsense
https://www.atsb.gov.au/media/3532398/ao2008070.pdf
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360+ hours, 207+ flights to test. Ok. I really would like to know how many of those flights included removing one AoA probe at a random time (physically, not software disable), how many were done in the dark during rain, how many were done with some kind of heavy turbulence, how many were done acting like AF447, how many was done going nose down at high speed.
I know, test flights are there to collect parameters that you can analyze, replicate in the sim, and so on.
But given that MCAS was (not) really tested before and nobody even knew it was a new thing, I hope that Boing has gone to the limits to prove that it is fixed and that all those "undertrained, third world, below average, slow procedure followers" will be able to "just keep flying" if MCAS is active again. Or, even worst, it doesn't activate anymore when it was necessary (since I consider it existed to do something important and wasn't created just to keep engineers doing something in the spare time).
I know, test flights are there to collect parameters that you can analyze, replicate in the sim, and so on.
But given that MCAS was (not) really tested before and nobody even knew it was a new thing, I hope that Boing has gone to the limits to prove that it is fixed and that all those "undertrained, third world, below average, slow procedure followers" will be able to "just keep flying" if MCAS is active again. Or, even worst, it doesn't activate anymore when it was necessary (since I consider it existed to do something important and wasn't created just to keep engineers doing something in the spare time).
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Well, everyone knows that "pilots of a certain colour" are inferior to American pilots.
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I suspect the unfortunate comments were regarding pilots background and exposure to training, as opposed to any racial implications, but of course, when one wants to criticize another, instead of an intelligent discussion, it's always easier to cry "racist", quite a popular approach in the USA these days
I always thought Canadian and American pilots were interchangeable anyways, I've known many Canadians flying for US carriers, think one I knew was a former Snowbird team member as well...never saw much difference except maybe the use of the expression "eh"...
I always thought Canadian and American pilots were interchangeable anyways, I've known many Canadians flying for US carriers, think one I knew was a former Snowbird team member as well...never saw much difference except maybe the use of the expression "eh"...
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I suspect the unfortunate comments were regarding pilots background and exposure to training, as opposed to any racial implications, but of course, when one wants to criticize another, instead of an intelligent discussion, it's always easier to cry "racist", quite a popular approach in the USA these days
I always thought Canadian and American pilots were interchangeable anyways, I've known many Canadians flying for US carriers, think one I knew was a former Snowbird team member as well...never saw much difference except maybe the use of the expression "eh"...
I always thought Canadian and American pilots were interchangeable anyways, I've known many Canadians flying for US carriers, think one I knew was a former Snowbird team member as well...never saw much difference except maybe the use of the expression "eh"...
"This is done in recognition that there are airline pilots that are not capable of recognizing and mitigating certain system failures. It is a shame that it took two accidents with many fatalities to understand this, but it is not fair or reasonable to assert that Boeing and the FAA should have known the exact point when systems would become too complex for certain pilots."
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http://hoh-aero.com/home.htm
http://hoh-aero.com/FAA%20Rudder/AIA...er%20Paper.pdf
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[QUOTE=ironbutt57;10473997
I always thought Canadian and American pilots were interchangeable anyways, I've known many Canadians flying for US carriers, think one I knew was a former Snowbird team member as well...never saw much difference except maybe the use of the expression "eh"...[/QUOTE]
Well I am a US citizen, living in Vermont who flew for a Canadian carrier , out of Montreal for 32 years. The pilots I flew with said I had developed a New England accent..At least I could understand the Boston and New York controllers. as in., "You got the GW?..follow the Hudson".
As far as Canadian competency goes, I flew with highly trained pilots. One, a Canadian F/O, who on an exchange program with the US Navy, was carrier qualified, on the Hornet. Another F/O I flew with, did an exchange program with the USAF, was qualified on the F-15, and served with a Squadron in Alaska.
I always thought Canadian and American pilots were interchangeable anyways, I've known many Canadians flying for US carriers, think one I knew was a former Snowbird team member as well...never saw much difference except maybe the use of the expression "eh"...
[/QUOTE]Well I am a US citizen, living in Vermont who flew for a Canadian carrier , out of Montreal for 32 years. The pilots I flew with said I had developed a New England accent..At least I could understand the Boston and New York controllers. as in., "You got the GW?..follow the Hudson".
As far as Canadian competency goes, I flew with highly trained pilots. One, a Canadian F/O, who on an exchange program with the US Navy, was carrier qualified, on the Hornet. Another F/O I flew with, did an exchange program with the USAF, was qualified on the F-15, and served with a Squadron in Alaska.
Last edited by Retired DC9 driver; 19th May 2019 at 19:17.
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I fly for an airline which has a world renowned safety record which was even once mentioned in a Hollywood movie. I’ve flown with some highly competent pilots here, but also a small handful who make me openly wonder how they got where they are.
The point is that none of us are perfect (though we traditionally like to think we are) even in modern western airlines with excellent records, and before we throw rocks at the deceased pilots here, maybe we should ascertain the facts and whether any average competent pilot, faced with the same situation at the same time, would truly have done any better (and at this point I’m far from convinced they could’ve).
The point is that none of us are perfect (though we traditionally like to think we are) even in modern western airlines with excellent records, and before we throw rocks at the deceased pilots here, maybe we should ascertain the facts and whether any average competent pilot, faced with the same situation at the same time, would truly have done any better (and at this point I’m far from convinced they could’ve).