6 ms·

I was honestly under the impression that the provided checklist did not work, as it included elements that did not work in the 737-MAX as expected when coming f

by onli 7y ago

I was honestly under the impression that the provided checklist did not work, as it included elements that did not work in the 737-MAX as expected when coming from earlier models. Plus the fact that the forces were to strong, the pilot could not manually correct the course. Besides, did the pilots have opportunity to read and implement the new checklist?

sokoloff 7y ago
There was no new checklist. (Arguably, this may be a problem.) The existing checklist was unchanged from other 737s and the required actions were all "memory items" (items which must be recalled and implemented by the crew from memory, prior to referencing and completing the written checklist in the QRH). Any 737 crewmember would have had to have demonstrated those checklist items, from memory, prior to receiving their type-rating to fly the jet. Runaway trim is a "no joke" event in nearly any type and is a memory item in any type I'm familiar with. The Ethiopian Air crew seemed to correctly diagnose the issue, got the aircraft somewhat under control and then, in an attempt to fix the trim issue, undid the corrective checklist item, ran the trim aircraft-nose-up using the thumb switch (so far, excellent!!) and then, inexplicably, left the stab trim power enabled without commanding further aircraft-nose-up. So, they diagnosed the issue, initially did all the right things, then undid them [with good reason], then failed to re-do them. (I agree that Boeing still wears a lot of blame here. It's just not the case that the crews were helpless and unaware passengers.)
- onli 7y ago
  Well, okay. https://www.theverge.com/2019/5/2/18518176/boeing-737-max-crash-problems-human-error-mcas-faa https://www.theverge.com/2019/5/2/18518176/boeing-737-max-cr... agrees (though I vehemently disagree with its title when interpreting it as referring to pilot errors! But that might be the point). Problem seems to be that it was basically impossible to realize which checklist to follow and to identify the problem. I think my sentence when interpreted with that in mind still works (and you are still right as well): Pilots had no opportunity (several reasons, like not being informed about system changes) to save the plane, but not it was 100% impossible during the whole incident to save the plane (it was probably impossible after they deactivated the electric trim system).
- mannykannot 7y ago
  It's not just the checklist: the experience of MCAS-induced trim runaway is significantly different from that which NG pilots are trained for, to the point where additional training seems necessary. Boeing set up the conditions for an accident by first hiding, and then downplaying, those differences, apparently to avoid additional training being required. I have seen some suggestions that this was also the reason for not having MCAS compare the two AofA sources to detect a fault, as the fault would have to be reported, and the documentation of that indicator would reveal the existence of MCAS.
  - sokoloff 7y ago
    I agree with you, hence the "arguably, this may be a problem" parenthetical. Nevertheless, the provided checklist did work as evidenced by Lion Air 043.
    - mannykannot 7y ago
      So the checklist worked sometimes, but the question is, could it have been improved if we put aside the issue of whether doing so would make a case for additional training? It is quite possible that it would have been an adequate checklist when backed up with sufficient training that emphasized the differences between MCAS-induced trim runaway and that which might have been experienced in other variants. Simulator practice of manually trimming might help as well, though there is some doubt whether current simulators can adequately model the difficulties that may be experienced. https://www.youtube.com/watch?v=n4qDLR4s45U&t=296s https://www.youtube.com/watch?v=n4qDLR4s45U&t=296s
    - salawat 7y ago
      Note: the penultimate flight had the luxury of a third pilot in the cockpit with nothing else to do than to pay attention to anything the other two pilots couldn't. Also, that "checklist", and he existence of MCAS, was not even commonly known until after Lion Air went down. The secrecy behind this is largely attributed to Boeing trying to keep MCAS from intense scrutiny by the FAA, based on whistleblower testimony reported in the 60 Minutes Expose. https://m.youtube.com/watch%3Fv%3DaO7_indbfME&ved=2ahUKEwiPp72Ar57jAhXBK80KHQrCCZ4QwqsBMAB6BAgHEAU&usg=AOvVaw2APCLXMqKKxa5mxQOnsmvo https://m.youtube.com/watch%3Fv%3DaO7_indbfME&ved=2ahUKEwiPp...

by onli 7y ago

sokoloff 7y ago

There was no new checklist. (Arguably, this may be a problem.) The existing checklist was unchanged from other 737s and the required actions were all "memory items" (items which must be recalled and implemented by the crew from memory, prior to referencing and completing the written checklist in the QRH). Any 737 crewmember would have had to have demonstrated those checklist items, from memory, prior to receiving their type-rating to fly the jet. Runaway trim is a "no joke" event in nearly any type and is a memory item in any type I'm familiar with. The Ethiopian Air crew seemed to correctly diagnose the issue, got the aircraft somewhat under control and then, in an attempt to fix the trim issue, undid the corrective checklist item, ran the trim aircraft-nose-up using the thumb switch (so far, excellent!!) and then, inexplicably, left the stab trim power enabled without commanding further aircraft-nose-up. So, they diagnosed the issue, initially did all the right things, then undid them [with good reason], then failed to re-do them. (I agree that Boeing still wears a lot of blame here. It's just not the case that the crews were helpless and unaware passengers.)

onli 7y ago
Well, okay. https://www.theverge.com/2019/5/2/18518176/boeing-737-max-crash-problems-human-error-mcas-faa https://www.theverge.com/2019/5/2/18518176/boeing-737-max-cr... agrees (though I vehemently disagree with its title when interpreting it as referring to pilot errors! But that might be the point). Problem seems to be that it was basically impossible to realize which checklist to follow and to identify the problem. I think my sentence when interpreted with that in mind still works (and you are still right as well): Pilots had no opportunity (several reasons, like not being informed about system changes) to save the plane, but not it was 100% impossible during the whole incident to save the plane (it was probably impossible after they deactivated the electric trim system).
mannykannot 7y ago
It's not just the checklist: the experience of MCAS-induced trim runaway is significantly different from that which NG pilots are trained for, to the point where additional training seems necessary. Boeing set up the conditions for an accident by first hiding, and then downplaying, those differences, apparently to avoid additional training being required. I have seen some suggestions that this was also the reason for not having MCAS compare the two AofA sources to detect a fault, as the fault would have to be reported, and the documentation of that indicator would reveal the existence of MCAS.
- sokoloff 7y ago
  I agree with you, hence the "arguably, this may be a problem" parenthetical. Nevertheless, the provided checklist did work as evidenced by Lion Air 043.
  - mannykannot 7y ago
    So the checklist worked sometimes, but the question is, could it have been improved if we put aside the issue of whether doing so would make a case for additional training? It is quite possible that it would have been an adequate checklist when backed up with sufficient training that emphasized the differences between MCAS-induced trim runaway and that which might have been experienced in other variants. Simulator practice of manually trimming might help as well, though there is some doubt whether current simulators can adequately model the difficulties that may be experienced. https://www.youtube.com/watch?v=n4qDLR4s45U&t=296s https://www.youtube.com/watch?v=n4qDLR4s45U&t=296s
  - salawat 7y ago
    Note: the penultimate flight had the luxury of a third pilot in the cockpit with nothing else to do than to pay attention to anything the other two pilots couldn't. Also, that "checklist", and he existence of MCAS, was not even commonly known until after Lion Air went down. The secrecy behind this is largely attributed to Boeing trying to keep MCAS from intense scrutiny by the FAA, based on whistleblower testimony reported in the 60 Minutes Expose. https://m.youtube.com/watch%3Fv%3DaO7_indbfME&ved=2ahUKEwiPp72Ar57jAhXBK80KHQrCCZ4QwqsBMAB6BAgHEAU&usg=AOvVaw2APCLXMqKKxa5mxQOnsmvo https://m.youtube.com/watch%3Fv%3DaO7_indbfME&ved=2ahUKEwiPp...