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A comment on Ethiopian Airlines 737 MAX Investigation Preliminary Report. Parent comment

Re:Ethiopian Airlines 737 MAX Investigation Preliminary Report by paulmd on Thursday April 04, 2019 @05:02PM (#19577079)
Because right after takeoff is the single most common point at which you might stall the aircraft. What's more, at that point it is likely to be a power-on stall, which is the specific situation that MCAS is intended to fix (because the 737 MAX has a tendency to pitch upwards in power-on scenarios).

Really there should just have been a separate cutout for MCAS itself, but that would have triggered retraining requirements, so Boeing wanted to avoid that. But very simply, there should just be an 'off' switch to disable this system if it starts to run away, distinct from the whole runaway trim procedure.

(as well as 2-of-3 redundancy on the sensors, the lack of redundancy is seriously exacerbating the rate of incorrect MCAS system activations)

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Re:Ethiopian Airlines 737 MAX Investigation Preliminary Report by cjbprime on Thursday April 04, 2019 @07:12PM (#19578044)
> is the specific situation that MCAS is intended to fix

Well, not quite: if they wanted it to protect against stalls at very low altitude, it would be operational with flaps extended.

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Re:Ethiopian Airlines 737 MAX Investigation Preliminary Report by kalleboo on Friday April 05, 2019 @12:53AM (#19579808)
And the AoA disagree needs to be actually used and not just an "option feature pilot warning". AoA disagree on ground = plane doesn't take off. In flight = MCAS cuts out.
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Re:Ethiopian Airlines 737 MAX Investigation Preliminary Report by cjbprime on Friday April 05, 2019 @01:28AM (#19579965)
You can't have an AoA disagreement when stationary on the ground. It is a wind vane.
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Re:Ethiopian Airlines 737 MAX Investigation Preliminary Report by djmips on Friday April 05, 2019 @02:07AM (#19580113)
You don't know that. If it's malfunctioning it could be in the electronics and nothing to do with how it operates.
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Re:Ethiopian Airlines 737 MAX Investigation Preliminary Report by cjbprime on Friday April 05, 2019 @01:55PM (#19585285)
And if it's reporting a difference, it could just be because there's no airflow and the vanes aren't at identical positions. You can't rely on the difference meaning anything.
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