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Unfortunately, the Ethiopian crash did pretty much everything they were told to do (disable electric stabilizer trim) for the alleged 'memory checklist' procedu

Unfortunately, the Ethiopian crash did pretty much everything they were told to do (disable electric stabilizer trim) for the alleged 'memory checklist' procedure and it still wasn't enough. "Crappy sensor failure, crappy software failure, crappy aerodynamic failure" would be the chain of events, because the pilots did everything right.

theclaw 8y ago
Not everyone agrees. There is some argument over why they did not throttle back and ended up overspeeding, which meant they could not manually trim, and why they re-engaged automatic stabiliser trim when the memory items explicitly state not to do so. The throttles were at maximum during the entire episode. My understanding is somewhat limited but I’ve read that the stick shaker activation might have made them leave the throttles alone, and that they may have re-enabled automatic trim because the manual trim wheels were impossible to move at such high velocity. Re-enabling auto trim is what ultimately allowed MCAS to push the nose down for the last time, but it’s not clear to me as a layman whether they could have saved the plane given their situation prior to re-enabling it anyway.
acqq 8y ago
Reading a lot of detailed reports, I concluded that nobody at Boeing ever properly tested the conditions that happened by both Lion Air and Ethiopian, until much after the second crash. Boeing didn't do enough steps to reconstruct what happened by Lion Air, otherwise they would have never published totally useless procedure which was then followed by the pilots of Ethiopian. The actual testing in the proper simulator would have shown that the emergency procedure, as written by Boeing after Lion Air crash, just can't work. The pilots in Ethiopian and all the passengers paid with their lives for a whole world to learn that. The world knows because one pilot tried to partially reconstruct the conditions on his own in an older simulator, as there were effectively almost no new simulators because the Boeing's selling point was that the new model of the plane is same as an old one model, just to avoid the recertification and pilot retraining. So the said pilot did the test for youtube, showed that what the pilots probably did matched the emergency procedure, and that exactly that following the procedure most probably results in the crash, but had to remove the video once his employer became aware of what he did. I've posted the link to that original source then, but HN moderators marked it then as a "dupe": https://leehamnews.com/2019/04/03/et302-used-the-cut-out-switches-to-stop-mcas/ https://leehamnews.com/2019/04/03/et302-used-the-cut-out-swi...

theclaw 8y ago

Not everyone agrees. There is some argument over why they did not throttle back and ended up overspeeding, which meant they could not manually trim, and why they re-engaged automatic stabiliser trim when the memory items explicitly state not to do so. The throttles were at maximum during the entire episode. My understanding is somewhat limited but I’ve read that the stick shaker activation might have made them leave the throttles alone, and that they may have re-enabled automatic trim because the manual trim wheels were impossible to move at such high velocity. Re-enabling auto trim is what ultimately allowed MCAS to push the nose down for the last time, but it’s not clear to me as a layman whether they could have saved the plane given their situation prior to re-enabling it anyway.

acqq 8y ago

Reading a lot of detailed reports, I concluded that nobody at Boeing ever properly tested the conditions that happened by both Lion Air and Ethiopian, until much after the second crash. Boeing didn't do enough steps to reconstruct what happened by Lion Air, otherwise they would have never published totally useless procedure which was then followed by the pilots of Ethiopian. The actual testing in the proper simulator would have shown that the emergency procedure, as written by Boeing after Lion Air crash, just can't work. The pilots in Ethiopian and all the passengers paid with their lives for a whole world to learn that. The world knows because one pilot tried to partially reconstruct the conditions on his own in an older simulator, as there were effectively almost no new simulators because the Boeing's selling point was that the new model of the plane is same as an old one model, just to avoid the recertification and pilot retraining. So the said pilot did the test for youtube, showed that what the pilots probably did matched the emergency procedure, and that exactly that following the procedure most probably results in the crash, but had to remove the video once his employer became aware of what he did. I've posted the link to that original source then, but HN moderators marked it then as a "dupe": https://leehamnews.com/2019/04/03/et302-used-the-cut-out-switches-to-stop-mcas/ https://leehamnews.com/2019/04/03/et302-used-the-cut-out-swi...