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Why? What I've heard is that if the pilots know how to disable the pitch correction, the plane won't fight them in the event of a sensor failure and they can la

Why? What I've heard is that if the pilots know how to disable the pitch correction, the plane won't fight them in the event of a sensor failure and they can land safely.

ghayes 7y ago
From what I've heard, trimming a large jet engine plane by hand is physically difficult, even if you manage to disable the MCAS system. Additionally, I believe the core issue is that pilots were meant to fly these plans without additional retraining, which is why MCAS was added in the first place.
underwater 7y ago
Isn't that exactly what happened with Ethiopian Airlines? The pilots knew about the MCAS, knew what was happening, disabled the system, but were unable to physically adjust the trim to prevent the crash?
- theclaw 7y ago
  I’ve not read anything that suggested they knew about MCAS. They knew about automatic stabiliser trim, which is a different system also present on the older 737 NG. The way MCAS monitors angle of attack, and the way it is temporarily disabled by pilot trim inputs was not known to them.
  - kevin_thibedeau 7y ago
    They followed the recovery checklist. Step 1: Use the trim cut-out switches to stop MCAS. After the first crash, any MAX pilot would have to be a moron to not be informed about the issue and Boeing's (useless) guidance to resolve it.
    - theclaw 7y ago
      Yes I agree, they knew about the possibility of runaway stabiliser and they were not morons. Boeing’s guidance was useless to them because it left out a description of how MCAS operates, and I’m not sure it even mentioned it by name but I may be wrong on that. If they had known that MCAS is disabled for 15 seconds by pilot trim inputs, they could have saved the plane. Toward the end of the flight they went off-book and re-enabled auto trim, blipped the trim a few times and 15 seconds later MCAS jumps on and dives them into the ground. All they needed to do was keep making small trims.
      - acqq 7y ago
        > If they had known that MCAS is disabled for 15 seconds by pilot trim inputs, they could have saved the plane. I understand it as "if they were able to consistently, all the time, until they land, fight the plane which was trying to kill them every 15 seconds turning the nose to the ground, resulting all the time in even harder position (due to the forces involved) they would..." Flying death trap indeed.

Why? What I've heard is that if the pilots know how to disable the pitch correction, the plane won't fight them in the event of a sensor failure and they can land safely.

ghayes 7y ago

From what I've heard, trimming a large jet engine plane by hand is physically difficult, even if you manage to disable the MCAS system. Additionally, I believe the core issue is that pilots were meant to fly these plans without additional retraining, which is why MCAS was added in the first place.

underwater 7y ago

Isn't that exactly what happened with Ethiopian Airlines? The pilots knew about the MCAS, knew what was happening, disabled the system, but were unable to physically adjust the trim to prevent the crash?

theclaw 7y ago
I’ve not read anything that suggested they knew about MCAS. They knew about automatic stabiliser trim, which is a different system also present on the older 737 NG. The way MCAS monitors angle of attack, and the way it is temporarily disabled by pilot trim inputs was not known to them.
- kevin_thibedeau 7y ago
  They followed the recovery checklist. Step 1: Use the trim cut-out switches to stop MCAS. After the first crash, any MAX pilot would have to be a moron to not be informed about the issue and Boeing's (useless) guidance to resolve it.
  - theclaw 7y ago
    Yes I agree, they knew about the possibility of runaway stabiliser and they were not morons. Boeing’s guidance was useless to them because it left out a description of how MCAS operates, and I’m not sure it even mentioned it by name but I may be wrong on that. If they had known that MCAS is disabled for 15 seconds by pilot trim inputs, they could have saved the plane. Toward the end of the flight they went off-book and re-enabled auto trim, blipped the trim a few times and 15 seconds later MCAS jumps on and dives them into the ground. All they needed to do was keep making small trims.
    - acqq 7y ago
      > If they had known that MCAS is disabled for 15 seconds by pilot trim inputs, they could have saved the plane. I understand it as "if they were able to consistently, all the time, until they land, fight the plane which was trying to kill them every 15 seconds turning the nose to the ground, resulting all the time in even harder position (due to the forces involved) they would..." Flying death trap indeed.