Ethiopian Pilots Followed Boeing’s Required Steps to Disable 737 Max System

https://www.wsj.com/articles/ethiopian-airlines-pilots-initially-followed-boeings-required-emergency-steps-to-disable-737-max-system-11554263276

by radicaldreamer • 7 years ago

12 5 7 years ago

wsj.com

themark• 7 years ago

I am not surprised. When do we start to consider the possibility that the software was compromised?

js22• 7 years ago

Something is not adding up:

The pilots on Ethiopian Airlines Flight 302 initially reacted to the emergency by shutting off power to electric motors driven by the automated system, these people said, but then appear to have re-engaged the system to cope with a persistent steep nose-down angle. It wasn’t immediately clear why the pilots turned the automated system back on instead of continuing to follow Boeing’s standard emergency checklist, but government and industry officials said the likely reason would have been because manual controls to raise the nose didn’t achieve the desired results.

After first cranking a manual wheel in the cockpit that controls the same movable surfaces on the plane’s tail that MCAS had affected, the pilots turned electric power back on, one of these people said. They began to use electric switches to try to raise the plane’s nose, according to these people. But the electric power also reactivated MCAS, allowing it to continue its strong downward commands, the people said.

Did they just not crank the wheels enough? The motor operates quickly so it would take a lot of hand cranking to return the trim to neutral. Maybe they hadn't practiced the manual procedure before and were unaware of how many turns were needed?

LoSboccacc• 7 years ago

well is there an indication on how long does it takes to come out of full trim manually? because if it's 30 seconds of cranking the aircraft might very well be descending too fast or too fast in general by the time control is regained.

js22• 7 years ago

It’s a lot of cranking to do by hand[1]. You could use the electric trim to reset back to zero and then disable electric trim. (But, that isn’t the procedure.)

1. https://youtu.be/xixM_cwSLcQ

Ethiopian Pilots Followed Boeing’s Required Steps to Disable 737 Max System

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