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Most people would find it reasonable to expect a pilot to have experienced flight conditions in the area outside the certification limits, if it is reasonably probable that the aircraft will be in this condition. |
In response to this:
Most people would find it reasonable to expect a pilot to have experienced flight conditions in the area outside the certification limits, if it is reasonably probable that the aircraft will be in this condition.
Originally Posted by Fortissimo
(Post 10453927)
I don't find it reasonable at all. Unless you are a qualified test pilot, you should not be going outside the certification envelope.
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fizz,
It's very easy to sort these things out with hindsight and when sitting comfortably in an armchair! |
Originally Posted by Bergerie1
(Post 10453658)
How many of us would have diagnosed the problem correctly in the time available? |
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Originally Posted by FullWings
(Post 10453869)
What it screams to me is that the pilot(s) were so overloaded by control forces / stick shake / aural and visual warnings / general confusion that they had reverted to “pull back to make the houses look smaller” and had fixated on this due to saturation of their input channels. The trim running could well be the gorilla in the room, if you’ve seen the video.
I used to do basic flight instruction, and I’ve seen many types of students. I would often tell them that flying an aircraft on a nice day really wasn’t that difficult once you had a little time under your belt, not too unlike learning to drive an automobile. The huge difference between a car and a plane, of course, is that you just can’t pull an aircraft over on the shoulder when things go wrong. You have to take whatever comes, work with whatever you have, and do your damnedest to get the aircraft safely back on the ground. I would tell my students that if they could not deal with that reality, then they should not become a pilot. As professional pilots, we ought to meet an even much higher standard. When things started to go wrong, at least one of these pilots needed to look past the noise, place their hands firmly on the yoke and throttles, set the proper attitude and power settings, keep the aircraft in trim, and stay away from the rocks. That was all that was required. Everything else could have waited. The plane wasn’t on fire, the wing didn’t fall off, there were no bombs on board. This plane was flyable. Yes, Boeing fracked up. Yes, the FAA and the airlines were culpable of going along with the fiction that the MAX wasn’t really that much different from the NG. But you know what? On any given day someone else could screw up and give us an aircraft that will malfunction in a unique and potentially dangerous way. And as always, the pilots are the last line of defense. We need to be mentally prepared for that reality or find another line of work. |
Originally Posted by GordonR_Cape
(Post 10451495)
Many pages back, in another thread LEOCh posted a schematic chart showing a nasty inflection between 10 and 15 degrees AOA, which is when MCAS kicks in. Once AOA is below 10 degrees, MCAS unwinds the nose-down trim (unless the pilots intervene with electrical trim inputs
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Originally Posted by Water pilot
(Post 10454043)
This seems like rather complex behavior for the pilots not to be informed about or trained on, especially in a plane that is not advertised as a fly by wire plane. When exactly does MCAS start to unwind the trim and in the worst case scenario how much uncommanded nose down trim does the pilot have to unwind if they happen to have blipped the trim switch at the wrong point in the unwind scenario?
The assumption must be that the pilot would not "porpoise" the aircraft with the elevator, alternately crossing the MCAS 10 degree AOA threshold. This criterion requires time-smoothing, to avoid random fluctuations of the AOA values (as per the new specification). Blipping the electric trim (either up or down) during the unwind process, could theoretically put the aircraft in a semi-unstable situation, since MCAS would be disabled, and cannot reactivate again (as per the new specification). Again we must assume that the pilot intentionally wants to keep the nose high for specific reasons (such as high-altitude terrain proximity avoidance). In this scenario MCAS should not try to second guess the flight situation, but rather wait for the pilot to release the elevator yoke (and sort out any trim issues later). Presumably the MCAS system will be clearly documented to the point where pilots are assured that: - MCAS will not inhibit the necessary elevator yoke authority during escape maneuvers - The overall flight system will not produce an out of trim condition when exiting from a maneuver I seems obvious that Boeing and the FAA will flight test all of this in great detail. Whether an average pilot needs to experience this in a simulator, is an entirely different question (conditions outside the normal flight envelope). The time-delay feedback process is indeed new, and somewhat uncharted territory. |
Originally Posted by 737 Driver
(Post 10454038)
- Yes, I’ve seen the video, and yes I agree that it appears the Captain had achieved cognitive overload. Where I differ is that I feel the circumstances were not so extreme that cognitive overload would have been a reasonable expectation of a 737 type-rated Captain. I used to do basic flight instruction, and I’ve seen many types of students. I would often tell them that flying an aircraft on a nice day really wasn’t that difficult once you had a little time under your belt, not too unlike learning to drive an automobile. The huge difference between a car and a plane, of course, is that you just can’t pull an aircraft over on the shoulder when things go wrong. You have to take whatever comes, work with whatever you have, and do your damnedest to get the aircraft safely back on the ground. I would tell my students that if they could not deal with that reality, then they should not become a pilot. As professional pilots, we ought to meet an even much higher standard. When things started to go wrong, at least one of these pilots needed to look past the noise, place their hands firmly on the yoke and throttles, set the proper attitude and power settings, keep the aircraft in trim, and stay away from the rocks. That was all that was required. Everything else could have waited. The plane wasn’t on fire, the wing didn’t fall off, there were no bombs on board. This plane was flyable. Yes, Boeing fracked up. Yes, the FAA and the airlines were culpable of going along with the fiction that the MAX wasn’t really that much different from the NG. But you know what? On any given day someone else could screw up and give us an aircraft that will malfunction in a unique and potentially dangerous way. And as always, the pilots are the last line of defense. We need to be mentally prepared for that reality or find another line of work. |
Originally Posted by Chronus
(Post 10454095)
I couldn`t disagree more. To fly the modern airliners you fly the automatics. If for whatever reason you cannot do that then its very much up to the avionics to do whatever they have been setup to do. These guys did not have a cats in hell chance of persuading the automatics to allow them to interfere. They simply lost the very short argument with the machine. What sort of last line of defense is that, is it a bit like the Maginot Line, invincible until proven otherwise and how many times does it need to be demonstrated before someone realises it aint working. Give me human error any day, I can understand that, computers, electronics and all that wizardry that goes with them, let the kids addicted to them play with it all, that would be a whole load safer.
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Originally Posted by 737 Driver
(Post 10454038)
As professional pilots, we ought to meet an even much higher standard. When things started to go wrong, at least one of these pilots needed to look past the noise, place their hands firmly on the yoke and throttles, set the proper attitude and power settings, keep the aircraft in trim, and stay away from the rocks. That was all that was required. Everything else could have waited. The plane wasn’t on fire, the wing didn’t fall off, there were no bombs on board. This plane was flyable. Yes, Boeing fracked up. Yes, the FAA and the airlines were culpable of going along with the fiction that the MAX wasn’t really that much different from the NG. But you know what? On any given day someone else could screw up and give us an aircraft that will malfunction in a unique and potentially dangerous way. And as always, the pilots are the last line of defense. We need to be mentally prepared for that reality or find another line of work.
Originally Posted by Chronus
(Post 10454095)
I couldn`t disagree more. To fly the modern airliners you fly the automatics. If for whatever reason you cannot do that then its very much up to the avionics to do whatever they have been setup to do. These guys did not have a cats in hell chance of persuading the automatics to allow them to interfere. They simply lost the very short argument with the machine. What sort of last line of defense is that, is it a bit like the Maginot Line, invincible until proven otherwise and how many times does it need to be demonstrated before someone realises it aint working. Give me human error any day, I can understand that, computers, electronics and all that wizardry that goes with them, let the kids addicted to them play with it all, that would be a whole load safer.
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Originally Posted by formulaben
(Post 10454103)
And I couldn't disagree any more with this. You're basically endorsing no airmanship.
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Originally Posted by 737 Driver
(Post 10454038)
- When things started to go wrong, at least one of these pilots needed to look past the noise, place their hands firmly on the yoke and throttles, set the proper attitude and power settings, keep the aircraft in trim, and stay away from the rocks. That was all that was required. Everything else could have waited. The plane wasn’t on fire, the wing didn’t fall off, there were no bombs on board. This plane was flyable. On any given day someone else could screw up and give us an aircraft that will malfunction in a unique and potentially dangerous way. And as always, the pilots are the last line of defense. We need to be mentally prepared for that reality or find another line of work. |
I am amazed at the continued "any real airman could have handled this... obvious trim runaway... follow the procedures" drumbeat from people who identify as US- or Euro-based pilots. (I say "identify" because at least one such got outed as a sim player.)
People! So far we know of only three occurrences of the basic failure (AoA sensor is bad from the start of roll, falsely high reading, high enough for stall warning, and it's the one driving MCAS today). Two resulted in total loss. The third was saved by a jumpseat rider who had attention to spare and a better view of the trim wheels. That is stark evidence that this failure sequence is dangerous in the extreme. Moreover, airlines all over the world have, in recent years, contributed to the industry's excellent safety record. Not too many signs that (not to put too fine a point on it) the ethnicity of the pilots or management is a big deal. |
Quote: Originally Posted by GordonR_Cape https://www.pprune.org/images/buttons/viewpost.gif Many pages back, in another thread LEOCh posted a schematic chart showing a nasty inflection between 10 and 15 degrees AOA, which is when MCAS kicks in. Once AOA is below 10 degrees, MCAS unwinds the nose-down trim (unless the pilots intervene with electrical trim inputs Water pilot: #4242 My bold. This seems like rather complex behavior for the pilots not to be informed about or trained on, especially in a plane that is not advertised as a fly by wire plane. When exactly does MCAS start to unwind the trim and in the worst case scenario how much uncommanded nose down trim does the pilot have to unwind if they happen to have blipped the trim switch at the wrong point in the unwind scenario? GordonR carries the logic forward in the next thread. |
Originally Posted by LowObservable
(Post 10454230)
I am amazed at the continued "any real airman could have handled this... obvious trim runaway... follow the procedures" drumbeat from people who identify as US- or Euro-based pilots. (I say "identify" because at least one such got outed as a sim player.)
People! So far we know of only three occurrences of the basic failure (AoA sensor is bad from the start of roll, falsely high reading, high enough for stall warning, and it's the one driving MCAS today). Two resulted in total loss. The third was saved by a jumpseat rider who had attention to spare and a better view of the trim wheels. That is stark evidence that this failure sequence is dangerous in the extreme. Moreover, airlines all over the world have, in recent years, contributed to the industry's excellent safety record. Not too many signs that (not to put too fine a point on it) the ethnicity of the pilots or management is a big deal. As a side note, I have invested a fair amount of personal time researching issues related to these accidents to include sifting through available aviation safety and accident databases. There have been plenty of other cases of commercial airline instrument failures leading to unexpected system responses and confusion among the crew. You just don’t hear about them because these events had a successful conclusion. 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. |
Originally Posted by Loose rivets
(Post 10454237)
Quote: Water pilot continues below, but a point I've been wondering about for ages. MCAS winds back after it's done its thing? So little has been made of this - apart from me - that I wondered if I'd misunderstood. However, it seems that if the PF uses the electric trim, this will not happen. Since there was extensive use of the thumb switch trim, I guess this is why MCAS at no stage put things back where it found them. Erm, did it? What a vital observation. GordonR carries the logic forward in the next thread. |
Originally Posted by Water pilot
(Post 10454043)
When exactly does MCAS start to unwind the trim and in the worst case scenario how much uncommanded nose down trim does the pilot have to unwind if they happen to have blipped the trim switch at the wrong point in the unwind scenario? |
Well at some stage waaaaaaaay back I read the unequivocal statement that it does. As mentioned, I couldn't understand why I wasn't hearing more about that.
Now, Squinty makes this vital point as well as the thumb switch factor. Doesn't there need to be a *working* AOA sensor that actually provides decreased AOA with the application of stabilizer by MCAS before MCAS will unwind? Why would unwind if it still thinks the AOA is too high? |
Originally Posted by 737 Driver
(Post 10454038)
- You have to take whatever comes, work with whatever you have, and do your damnedest to get the aircraft safely back on the ground. I would tell my students that if they could not deal with that reality, then they should not become a pilot. It is manufactures, authorities and airlines obligation to cater for this reality. Once again, unfortunately. |
As professional pilots, we ought to meet an even much higher standard. When things started to go wrong, at least one of these pilots needed to look past the noise, place their hands firmly on the yoke and throttles, set the proper attitude and power settings, keep the aircraft in trim, and stay away from the rocks. That was all that was required. Everything else could have waited. The plane wasn’t on fire, the wing didn’t fall off, there were no bombs on board. This plane was flyable. Yes, Boeing fracked up. Yes, the FAA and the airlines were culpable of going along with the fiction that the MAX wasn’t really that much different from the NG. But you know what? On any given day someone else could screw up and give us an aircraft that will malfunction in a unique and potentially dangerous way. And as always, the pilots are the last line of defense. We need to be mentally prepared for that reality or find another line of work. |
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