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> and underscores the importance of pilots understanding severe runaway trim recovery procedures. So we're back to blaming the pilots?

by tus87 7y ago

d1str0 7y ago
Nobody is saying that. That’s not even what this out of context quote is saying.
jfk13 7y ago
Sounds more like we're blaming the manufacturer for concealing the fact that pilots needed to be specifically (re-)trained for this plane if they were to have a chance of handling it successfully.
- blunte 7y ago
  Exactly. But such training should not be necessary because this problem was created by Boeing. Pilots really should have extensive emergency training, but that doesn't mean it's ok for the manufacturer to Add a new failure case to a previously fine aircraft.
  - olliej 7y ago
    [edit: leaving this here because I wrote so much :D I totally misread/interpreted the comment I was replying to, and am entirely in agreement :D ] In this case the "fix" is called the "roller coaster", but Boeing has removed the documentation regarding this from the manuals - specifically the Pilots could have 100% perfect recall of the entire 737-MAX documentation and it wouldn't have helped. This is 100% Boeing's responsibility: * They designed a system that overrode pilot control so that they could avoid a requirement to retrain pilots. MCAS existed specifically to maintain the perception of identical flight behaviour entirely to avoid the need for recertification and training. That is the only reason MCAS existed. * They had minimal (no?) documentation indicating it existed * They made a warning system to report that the system was faulty - literally they shipped a broken safety system: the warning was intended to be freely available, but it was incorrectly tied to a costly system, so even though it was meant to be a standard feature, it was not present. * The recommended recovery technique from their documentation was not physically possible, even when you knew exactly what you were meant to do. * The only technique to recover - the roller coaster - had been deliberately removed from the training and flight manuals. The pilots who managed to recover were only able to recover because they knew of the "solution" from old manuals that were published online after both crashes had occurred, by some non-Boeing website. Even then the pilots in the article said that they didn't believe it would be possible to recover once you got below 5000 feet. Now, exactly how was this in any way the pilot's fault? They were fully trained, they had clearly read the manuals provided by Boeing (they knew they were mean to be using the manual wheel thing), the warning system was non-functional due to a construction/software error in Boeing's control software, etc.
    - secabeen 7y ago
      Do we know how much the speed was a factor? Would slowing down have reduced the forces to make cranking the manual trip possible?
      - olliej 7y ago
        No, the only way to recover as far as I can tell is to do the roller coaster thing. From what I can make out MCAS points the plane at the ground, so it accelerates - I don’t know if it also increases thrust but if it’s meant to be anti-stall maybe it does? The only way to reduce load once you’re at those speeds with a faulty plane (as far as I can understand it) is to keep pointing to the ground and move the trim control a bit, pull up again (which reintroduces the load) to gain altitude, then point down again and repeat until you’ve defeated the unsafe aircraft.
pageandrew 7y ago
There were pilot crews that were able to successfully fend off MCAS's murderous tendencies, and there were pilot crews that were not. Ignoring this learning opportunity for better general pilot education would be a mistake. Pilots being better trained is always a good thing.
- jfk13 7y ago
  IIUC, those who did overcome the problem in the simulator lost around 8,000 feet of altitude in the process (despite presumably going into the simulator already knowing what they were going to be facing). It's not clear to me that the Ethiopian plane ever had enough altitude (above the ground) to allow for such a recovery.
  - cjbprime 7y ago
    If I recall, it did stay at around 12k altitude for a stable period of flight where MCAS was being successfully neutralized. It's in the Ethiopian report. The airspeed was way above limit, though, which would make everything harder, including the manual retrimming.
    - bronson 7y ago
      Remember that they left an airport about 7000 feet up and headed over mountains. It's unlikely the plane was ever more than a few thousand feet above ground level. Page 26 in Ethiopia's report: https://fearoflanding.com/files/2019/04/Preliminary-Report-B737-800MAX-ET-AVJ.pdf https://fearoflanding.com/files/2019/04/Preliminary-Report-B...
      - cjbprime 7y ago
        Thanks, I'd forgotten the numbers. They aren't quite as bad as you say. The Ethiopian report shows their radar elevation around 14k feet before the descent, so it seems they made it to around 7k feet AGL for a few minutes. Not enough to be able to give up 8k feet during a recovery, I agree.
daveguy 7y ago
That's pretty much the opposite, right? That the pilots would need to know an extreme emergency procedure. In other words you'd need a Sully level pilot to survive (and unsurvivable below a certain speed and height). If you ask me that's a damning indictment when a flawed autopilot results in a state like that.
- namirez 7y ago
  Except Sully actually screwed up and put the passengers life in danger by trying to land on water and rather than returning to the airport. https://www.cbsnews.com/news/ntsb-sully-could-have-made-it-back-to-laguardia/ https://www.cbsnews.com/news/ntsb-sully-could-have-made-it-b...
  - cjbprime 7y ago
    I don't know how you could read the article you linked and come away with that conclusion.
  - YokoZar 7y ago
    The link you included says the opposite of what you're implying. > under the circumstances the captain's decision to ditch into the Hudson River was the better choice, documents released Tuesday by a federal safety panel said > He also would have had no way of knowing that he would be successful, and therefore would have been risking the possibility of a catastrophic crash in a densely populated area.
  - Someone1234 7y ago
    This was disproven. And is a major plot point in the movie about Flight 1549 (Sully). From Wikipedia: > The NTSB used flight simulators to test the possibility that the flight could have returned safely to LaGuardia or diverted to Teterboro; only seven of the thirteen simulated returns to La Guardia succeeded, and only one of the two to Teterboro. > Furthermore, the NTSB report called these simulations unrealistic: "The immediate turn made by the pilots during the simulations did not reflect or account for real-world considerations, such as the time delay required to recognize the bird strike and decide on a course of action." A further simulation, in which a 35-second delay was inserted to allow for those, crashed.
salawat 7y ago
No, we're back to, "why the heck didn't Boeing honor the regulatory requirement for simulator training, and tell American it was the best you could do?" Clearly, the condition is recoverable, with simulator training. Throw in a triple redundant AoA sensor on top of the training, plus the inclusion of MCAS implementation details in the training material, and things would likely have had a much higher chance of being dealt with without loss of life. Would Boeing have had a harder sell? Yes. Would there have been a non-zero chance of losing out on the order? Yes. Would 300+ people currently be pulp? I think not. I have a great deal of respect for the skill pilots develop. They are only human however, and are therefore subject to the same weakness of not being omniscient. If MCAS was the bullet, Boeing's opaque communication, and refusal to not game aviation certification regulations was the gun. Of that, I'm fairly certain. What plays the trigger pull in this sordid affair is the last thing that remains to be declared, but there are some seriously bright neon signs pointing at either somewhere in Chicago, or at the culture as a whole at Boeing. Let the digging continue. Let's see how deep the rabbit hole goes.
- blunte 7y ago
  TFA said it was likely not recoverable under 5000 AGL.
  - deleted 7y ago
    [deleted]
  - salawat 7y ago
    Didn't read the entire thing. Going to register later. I actually wonder whether anyone with access to the simulator has tried pulsing the trim switches in sub 4 second intervals. Which depending on how the trim switches work, (I.e. are they continuously coupled, or do they act by moving around a discrete set-point) might be able to fend off MCAS by constantly resetting the time until reactivation long enough to give the trim system time to neutralize. If something like that were done, a recovery below 5000AGL may be possible. It's not by a long shot the most intuitive approach out there, and it doesn't generalize well, but for the specific MCAS behavior that's been revealed it may work. (If there's any 737 pilots out there with insight, I'd be giddy if you'd offer some perspective.)

> and underscores the importance of pilots understanding severe runaway trim recovery procedures. So we're back to blaming the pilots?

by tus87 7y ago

> and underscores the importance of pilots understanding severe runaway trim recovery procedures. So we're back to blaming the pilots?

d1str0 7y ago

Nobody is saying that. That’s not even what this out of context quote is saying.

jfk13 7y ago

Sounds more like we're blaming the manufacturer for concealing the fact that pilots needed to be specifically (re-)trained for this plane if they were to have a chance of handling it successfully.

blunte 7y ago
Exactly. But such training should not be necessary because this problem was created by Boeing. Pilots really should have extensive emergency training, but that doesn't mean it's ok for the manufacturer to Add a new failure case to a previously fine aircraft.
- olliej 7y ago
  [edit: leaving this here because I wrote so much :D I totally misread/interpreted the comment I was replying to, and am entirely in agreement :D ] In this case the "fix" is called the "roller coaster", but Boeing has removed the documentation regarding this from the manuals - specifically the Pilots could have 100% perfect recall of the entire 737-MAX documentation and it wouldn't have helped. This is 100% Boeing's responsibility: * They designed a system that overrode pilot control so that they could avoid a requirement to retrain pilots. MCAS existed specifically to maintain the perception of identical flight behaviour entirely to avoid the need for recertification and training. That is the only reason MCAS existed. * They had minimal (no?) documentation indicating it existed * They made a warning system to report that the system was faulty - literally they shipped a broken safety system: the warning was intended to be freely available, but it was incorrectly tied to a costly system, so even though it was meant to be a standard feature, it was not present. * The recommended recovery technique from their documentation was not physically possible, even when you knew exactly what you were meant to do. * The only technique to recover - the roller coaster - had been deliberately removed from the training and flight manuals. The pilots who managed to recover were only able to recover because they knew of the "solution" from old manuals that were published online after both crashes had occurred, by some non-Boeing website. Even then the pilots in the article said that they didn't believe it would be possible to recover once you got below 5000 feet. Now, exactly how was this in any way the pilot's fault? They were fully trained, they had clearly read the manuals provided by Boeing (they knew they were mean to be using the manual wheel thing), the warning system was non-functional due to a construction/software error in Boeing's control software, etc.
  - secabeen 7y ago
    Do we know how much the speed was a factor? Would slowing down have reduced the forces to make cranking the manual trip possible?
    - olliej 7y ago
      No, the only way to recover as far as I can tell is to do the roller coaster thing. From what I can make out MCAS points the plane at the ground, so it accelerates - I don’t know if it also increases thrust but if it’s meant to be anti-stall maybe it does? The only way to reduce load once you’re at those speeds with a faulty plane (as far as I can understand it) is to keep pointing to the ground and move the trim control a bit, pull up again (which reintroduces the load) to gain altitude, then point down again and repeat until you’ve defeated the unsafe aircraft.

pageandrew 7y ago

There were pilot crews that were able to successfully fend off MCAS's murderous tendencies, and there were pilot crews that were not. Ignoring this learning opportunity for better general pilot education would be a mistake. Pilots being better trained is always a good thing.

jfk13 7y ago
IIUC, those who did overcome the problem in the simulator lost around 8,000 feet of altitude in the process (despite presumably going into the simulator already knowing what they were going to be facing). It's not clear to me that the Ethiopian plane ever had enough altitude (above the ground) to allow for such a recovery.
- cjbprime 7y ago
  If I recall, it did stay at around 12k altitude for a stable period of flight where MCAS was being successfully neutralized. It's in the Ethiopian report. The airspeed was way above limit, though, which would make everything harder, including the manual retrimming.
  - bronson 7y ago
    Remember that they left an airport about 7000 feet up and headed over mountains. It's unlikely the plane was ever more than a few thousand feet above ground level. Page 26 in Ethiopia's report: https://fearoflanding.com/files/2019/04/Preliminary-Report-B737-800MAX-ET-AVJ.pdf https://fearoflanding.com/files/2019/04/Preliminary-Report-B...
    - cjbprime 7y ago
      Thanks, I'd forgotten the numbers. They aren't quite as bad as you say. The Ethiopian report shows their radar elevation around 14k feet before the descent, so it seems they made it to around 7k feet AGL for a few minutes. Not enough to be able to give up 8k feet during a recovery, I agree.

daveguy 7y ago

That's pretty much the opposite, right? That the pilots would need to know an extreme emergency procedure. In other words you'd need a Sully level pilot to survive (and unsurvivable below a certain speed and height). If you ask me that's a damning indictment when a flawed autopilot results in a state like that.

namirez 7y ago
Except Sully actually screwed up and put the passengers life in danger by trying to land on water and rather than returning to the airport. https://www.cbsnews.com/news/ntsb-sully-could-have-made-it-back-to-laguardia/ https://www.cbsnews.com/news/ntsb-sully-could-have-made-it-b...
- cjbprime 7y ago
  I don't know how you could read the article you linked and come away with that conclusion.
- YokoZar 7y ago
  The link you included says the opposite of what you're implying. > under the circumstances the captain's decision to ditch into the Hudson River was the better choice, documents released Tuesday by a federal safety panel said > He also would have had no way of knowing that he would be successful, and therefore would have been risking the possibility of a catastrophic crash in a densely populated area.
- Someone1234 7y ago
  This was disproven. And is a major plot point in the movie about Flight 1549 (Sully). From Wikipedia: > The NTSB used flight simulators to test the possibility that the flight could have returned safely to LaGuardia or diverted to Teterboro; only seven of the thirteen simulated returns to La Guardia succeeded, and only one of the two to Teterboro. > Furthermore, the NTSB report called these simulations unrealistic: "The immediate turn made by the pilots during the simulations did not reflect or account for real-world considerations, such as the time delay required to recognize the bird strike and decide on a course of action." A further simulation, in which a 35-second delay was inserted to allow for those, crashed.

salawat 7y ago

No, we're back to, "why the heck didn't Boeing honor the regulatory requirement for simulator training, and tell American it was the best you could do?" Clearly, the condition is recoverable, with simulator training. Throw in a triple redundant AoA sensor on top of the training, plus the inclusion of MCAS implementation details in the training material, and things would likely have had a much higher chance of being dealt with without loss of life. Would Boeing have had a harder sell? Yes. Would there have been a non-zero chance of losing out on the order? Yes. Would 300+ people currently be pulp? I think not. I have a great deal of respect for the skill pilots develop. They are only human however, and are therefore subject to the same weakness of not being omniscient. If MCAS was the bullet, Boeing's opaque communication, and refusal to not game aviation certification regulations was the gun. Of that, I'm fairly certain. What plays the trigger pull in this sordid affair is the last thing that remains to be declared, but there are some seriously bright neon signs pointing at either somewhere in Chicago, or at the culture as a whole at Boeing. Let the digging continue. Let's see how deep the rabbit hole goes.

blunte 7y ago
TFA said it was likely not recoverable under 5000 AGL.
- deleted 7y ago
  [deleted]
- salawat 7y ago
  Didn't read the entire thing. Going to register later. I actually wonder whether anyone with access to the simulator has tried pulsing the trim switches in sub 4 second intervals. Which depending on how the trim switches work, (I.e. are they continuously coupled, or do they act by moving around a discrete set-point) might be able to fend off MCAS by constantly resetting the time until reactivation long enough to give the trim system time to neutralize. If something like that were done, a recovery below 5000AGL may be possible. It's not by a long shot the most intuitive approach out there, and it doesn't generalize well, but for the specific MCAS behavior that's been revealed it may work. (If there's any 737 pilots out there with insight, I'd be giddy if you'd offer some perspective.)