Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive'

Re:Ethiopian Airlines Boeing 737 pilots 'could not stop nose... by sokoloff on Thursday April 04, 2019 @01:28PM (#19574887)

Ah. They'd have had to "roller coaster" the airplane (pitch up, then move the elevator surface towards neutral [so a net nose down]) to get the trim to move manually [the last step on the checklist]. Repeat as needed until the stab is trimmed within a range where it can move manually in unaccelerated flight.

That's an interesting possibility, which if they didn't know about it (I don't blame them), they may have felt they had no choice but to go "off checklist" and re-engage the electric trim system. I'd expect that would be in the context of "PF commands nose up pitch trim continuously while PNF engages the trim cutout to normal and monitors."

That's a tougher hand dealt the crew than I previously contemplated and if that's what they did, it's one for which I will owe them a retraction.

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Re:Ethiopian Airlines Boeing 737 pilots 'could not stop nose... by gomijacogeo on Friday April 05, 2019 @04:32AM (#19580769)

It's a shame that MCAS behavior wasn't fully explained after the first crash. If it had, they might have remembered that flaps disable MCAS. If I had to go "off checklist", I'd go: stab trim off -> flaps 1st detent -> stab trim on -> trim to neutral -> stab trim off for duration of flight -> flaps up -> manual flight for the duration. Still, that's all while you're pulling on the column like mad, all the indicators are lit, all the annunciations are going on, the stick shaker is going, you're going like a bat out of hell, and the ground is coming up at you. In the final seconds of flight, there was so much nose-down that they were pulling -2g.

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Re:Ethiopian Airlines Boeing 737 pilots 'could not stop nose... by gomijacogeo on Friday April 05, 2019 @04:37AM (#19580790)

Another thing we know now about MCAS is that it's locked out for 5 seconds after each trim switch operation. So, if you never have stab trim engaged for longer than 5 seconds a shot, you should be able to trim up the plane.

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Re:Ethiopian Airlines Boeing 737 pilots 'could not stop nose... by JshWright on Thursday April 04, 2019 @03:36PM (#19576270)

They never had the altitude to do that...

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