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392 points cjr | 4 comments | | HN request time: 1.148s | source
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fsckboy ◴[] No.44537714[source]
it makes sense to me that the pilot who said "I did not do it" actually did do it without realizing it, was supposed to be putting the landing gear up when he committed a muscle memory mistake. it happened around the time the landing gear should be up, and this explanation matches what was said in the cockpit, and the fact that the landing gear wasn't retracted. I think this idea was even floated initially by the youtube pilot/analysts I watch but dismissed as unlikely.
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dyauspitr ◴[] No.44538361[source]
If you shut off the engines a couple of dozen meters above ground shouldn’t every alarm be blaring or there should be some sort of additional lever you have to pull way out of the way to enable shutting off the engine that close to the ground.
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WalterBright ◴[] No.44538978[source]
Consider a case where the engine starts to violently vibrate. This can tear the structure apart. Delaying shutting off the engine can be catastrophic.

It's very hard to solve one problem without creating another. At some point, you just gotta trust the pilot.

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russdill ◴[] No.44540677[source]
If you read through the boeing procedures, if an engine fails just after take off you delay cutting throttle or hitting the cutoff until you have positive climb and pass a certain altitude. Specifically because a mistake here would be so incredibly catastrophic. The following number of steps and verbal cross checks for then shutting down the engine are quite daunting. Not something applicable here, but still interesting to learn about
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interestica ◴[] No.44541999[source]
That’s absolutely applicable here. It means that an engine cutoff shouldn’t be allowed at all during certain parts of flight. It’s not crazy to think that a design fix would be to prevent those engagements during certain parts of takeoff (a certain window). It’s fly by wire anyway so it could presumably be done programmatically.

MCAS was basically made to prevent user input that would send the plane into a dangerous angle. The computer overrode the inputs. So there’s precedent for something like it.

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WalterBright ◴[] No.44542716[source]
> The computer overrode the inputs.

This is incorrect. The manual stabilizer trim thumb switches override MCAS.

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interestica ◴[] No.44543370[source]
Are we not in agreement? MCAS overrode the inputs and the thumb switches could override MCAS?
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WalterBright ◴[] No.44546086[source]
The pilot's inputs are the thumb switches, and they override MCAS.

Additionally, the stab trim cutoff switch overrode both MCAS and the thumb switches.

Using both easily and successfully averts MCAS crashes, as proven in the first incident (there were three, but only two are reported on).

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1. throwaway48476 ◴[] No.44547325[source]
There were also a lot of MCAS near misses.
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2. WalterBright ◴[] No.44547882[source]
I only heard of one. I'm interested in others, if you have references.
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3. throwaway48476 ◴[] No.44548041[source]
https://www.dallasnews.com/business/airlines/2019/03/12/seve...

I just remember that it happened commonly enough to US pilots. American pilots always recovered quickly enough that it didn't make the news before the fatal crashes.

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4. WalterBright ◴[] No.44548431{3}[source]
Thank you, but it's behind a paywall. I did find this:

https://www.nytimes.com/2019/09/18/magazine/boeing-737-max-c...

which has detailed information, but I don't trust the NYT. The article also erroneously reports that the MCAS trim rate is twice the speed of manual trim. The trim rate for both is 0.27 degrees per second.