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> In both cases, the pilots didn't strictly follow procedure But would "the procedure" actually have saved the plane? I don't believe so. WalterBright is arg

by 3JPLW 7y ago

> In both cases, the pilots didn't strictly follow procedure But would "the procedure" actually have saved the plane? I don't believe so. WalterBright is arguing that the pilots should have known better than "the procedure" and done something different from what the checklists and memory items proscribed. I can't comment on doing so — as I'm not an airline pilot — but to put blame on pilots in this sort of situation without acknowledging Boeing's actions is beyond tasteless. IMHO Boeing is 100% responsible for the deaths.

gok 7y ago
Responsibility is a tricky thing in tragedies like this. In hindsight, yeah, Boeing undoubtedly should have made more noise about this possible failure condition, and/or tested the system better, and/or designed the stall-prevention system to deal with sensor failures more gracefully, and/or redesigned the wing, and/or spent more time on their simulators, and/or designed a whole new plane. But none of those options are risk-free in terms of safety. Making MCAS more complicated might have made it riskier and harder to test. A new airplane could have come with new problems (like the 787, which has nearly exploded in flight due to battery problems). I said "pick on" the pilots, not "blame" them. There were a lot of bad things that added up. In the case of the Lion Air flight, the maintenance staff signed off on the plane even though they were aware the angle-of-attack sensors were completely broken, which had nearly caused a crash on the previous flight. The previous flights' pilots also either didn't report this incident, or their report was disregarded. Then when the emergency occurred, the pilots didn't know what to do. There are many reasons that that any plane's trim system could have malfunctioned, and the black box data suggests the pilots would have been unable to manage any of them. So the plane was taking off in an non-airworthy state with pilots who didn't know how to deal with a common system failure and weren't told that a system had just malfunctioned hours previously on this exact aircraft. The MCAS failure was a match thrown into a kindling box of bad circumstances.
- 3JPLW 7y ago
  Ok, sure, but you're picking on the pilots for not following Boeing's procedure exactly. And at the same time, WalterBright is picking on them for attempting to follow the procedure. And at the same time, I'm arguing that it's unclear if Boeing's procedure would have saved them at all. The LionAir crash was a tragedy. The Ethiopian Airlines crash was not just a tragedy; it was a complete systemic failure to appropriately react.
WalterBright 7y ago
I specifically wrote "There's plenty of failure that needs to be dealt with all around with those accidents." That means Boeing, the airline, the FAA, and the pilots. To say that any one action is 100% of the cause is incorrect. Every point of failure needs to be corrected in the chain of events leading to the crash. > tasteless When you're trying to make airplanes safe, matters of taste, politics, emotions and legal culpability have nothing to do with it. The NTSB has a very good track record of dispassionately sticking to the facts, and I am looking forward to reading their report.
- 3JPLW 7y ago
  I completely agree. Here's the deal, though: this wasn't just one crash. It was two. The failure mode of the second was indeed different than the first: it was a failure of Boeing and the aviation authorities to appropriately respond to the first disaster. To propose that pilots should have willy-nilly flipped MCAS on and off based on your reading of the news is just staggering. What if there was another bug where turning on MCAS when there was an AoA disagree led to an instant plunge, regardless of etrim inputs? I'd bet you'd be critiquing those dead pilots for not following the checklist — and keeping MCAS off — in such a case.
  - WalterBright 7y ago
    Turning it back on is indeed what the EA pilots did after being unable to use the manual trim, if I read the account correctly, the MCAS re-engaged and caused the final plunge. That wasn't on the checklist. But if they'd also engaged the manual trim switches, it would have corrected the nose down. It's not willy-nilly nor staggering. The EAD (referenced in another post here) indeed talks about using the electric trim to fix the nose down problem, and then cutting off power to the system.
    - 3JPLW 7y ago
      Yes, indeed. It doesn't talk about turning STAB TRIM back on, though, nor does it talk about turning STAB TRIM on with etrim inputs already applied — that's what I was calling your homegrown protocol. My point is that it's easy to armchair quarterback the pilots whether they followed the checklist or went off checklist to do something better or worse. The problem started long before they got in the cockpit, though, and had been made evident once before at the cost of 189 lives. To continue to focus on pilots' actions at this point is missing the elephant for the flea.

by 3JPLW 7y ago

gok 7y ago

Responsibility is a tricky thing in tragedies like this. In hindsight, yeah, Boeing undoubtedly should have made more noise about this possible failure condition, and/or tested the system better, and/or designed the stall-prevention system to deal with sensor failures more gracefully, and/or redesigned the wing, and/or spent more time on their simulators, and/or designed a whole new plane. But none of those options are risk-free in terms of safety. Making MCAS more complicated might have made it riskier and harder to test. A new airplane could have come with new problems (like the 787, which has nearly exploded in flight due to battery problems). I said "pick on" the pilots, not "blame" them. There were a lot of bad things that added up. In the case of the Lion Air flight, the maintenance staff signed off on the plane even though they were aware the angle-of-attack sensors were completely broken, which had nearly caused a crash on the previous flight. The previous flights' pilots also either didn't report this incident, or their report was disregarded. Then when the emergency occurred, the pilots didn't know what to do. There are many reasons that that any plane's trim system could have malfunctioned, and the black box data suggests the pilots would have been unable to manage any of them. So the plane was taking off in an non-airworthy state with pilots who didn't know how to deal with a common system failure and weren't told that a system had just malfunctioned hours previously on this exact aircraft. The MCAS failure was a match thrown into a kindling box of bad circumstances.

3JPLW 7y ago
Ok, sure, but you're picking on the pilots for not following Boeing's procedure exactly. And at the same time, WalterBright is picking on them for attempting to follow the procedure. And at the same time, I'm arguing that it's unclear if Boeing's procedure would have saved them at all. The LionAir crash was a tragedy. The Ethiopian Airlines crash was not just a tragedy; it was a complete systemic failure to appropriately react.

WalterBright 7y ago

I specifically wrote "There's plenty of failure that needs to be dealt with all around with those accidents." That means Boeing, the airline, the FAA, and the pilots. To say that any one action is 100% of the cause is incorrect. Every point of failure needs to be corrected in the chain of events leading to the crash. > tasteless When you're trying to make airplanes safe, matters of taste, politics, emotions and legal culpability have nothing to do with it. The NTSB has a very good track record of dispassionately sticking to the facts, and I am looking forward to reading their report.

3JPLW 7y ago
I completely agree. Here's the deal, though: this wasn't just one crash. It was two. The failure mode of the second was indeed different than the first: it was a failure of Boeing and the aviation authorities to appropriately respond to the first disaster. To propose that pilots should have willy-nilly flipped MCAS on and off based on your reading of the news is just staggering. What if there was another bug where turning on MCAS when there was an AoA disagree led to an instant plunge, regardless of etrim inputs? I'd bet you'd be critiquing those dead pilots for not following the checklist — and keeping MCAS off — in such a case.
- WalterBright 7y ago
  Turning it back on is indeed what the EA pilots did after being unable to use the manual trim, if I read the account correctly, the MCAS re-engaged and caused the final plunge. That wasn't on the checklist. But if they'd also engaged the manual trim switches, it would have corrected the nose down. It's not willy-nilly nor staggering. The EAD (referenced in another post here) indeed talks about using the electric trim to fix the nose down problem, and then cutting off power to the system.
  - 3JPLW 7y ago
    Yes, indeed. It doesn't talk about turning STAB TRIM back on, though, nor does it talk about turning STAB TRIM on with etrim inputs already applied — that's what I was calling your homegrown protocol. My point is that it's easy to armchair quarterback the pilots whether they followed the checklist or went off checklist to do something better or worse. The problem started long before they got in the cockpit, though, and had been made evident once before at the cost of 189 lives. To continue to focus on pilots' actions at this point is missing the elephant for the flea.