Originally Posted by
wheelsright
safeteepee #5039
Do not disagree with anything in your post.
But do you think that it is possible to use electric trim to counteract MCAS before using the cut-out switches? I feel there is something being missed here. Clearly, it is intended by Boeing that you can, and that is the information that has been provided. Given, two crews appear to have failed to apply sufficient nose-up trim, I have a niggling doubt it is the whole story. I want a reason they failed to apply sufficient nose-up other than they were stupid. I realise there may not be a reason...
It has pretty well been established on this thread that pilot electric trim will work in all conditions (does not stall under load) and interrupts MCAS if active as shown by ET trace at ~05:40:27. This pilot trim input was possibly then interrupted by cutout switches.
Other than 'deer in headlights' loosing it I see a few possible factors:
1: Pilot accustomed to short blips not comprehending amount truly needed, this fits Lion Air when the FO was ineffective at the end when PIC handed over control while the Captain was mostly successful.
2: Trimming by column feel not position: May seem that AC is closer to trimmed than it is. In other words if you have been pulling really hard then just slightly hard may feel like close to trimmed, I am sure the pilot did not want to over trim given all the alarms.
This might explain ET first retrim at 05:4-:15. Unfortunately we don't have the column force graph, just position.
3: Some as yet to be revealed flaw that interferes with pilot trim inputs; one possibility is biomechanical factors related to actuation switches after prolonged pulling.
This is unlikely but could explain the final seconds of both accidents.
Hopefully the final reports will fully address this question.