Originally Posted by
MurphyWasRight
Why would pilots in a severe AND trim crisis merely blip the switches?
Is there any possibility that the extreme column forces could have interfered with the switches, either mechanically (including wiring etc) or biomechanically.?
By biomechanically I mean could the hand position and forces make the pilot believe he was pressing the switches when in fact he was not?
The FDR shows a 'bunt' with significant g-force due to the final MCAS stabiliser nose down trim. Until that point the trim was
stable nose low but unvarying, so they may not have
seen the need for (or possibility of) nose up trim. They may have severely underestimated the force of the nose down trim at high airspeed, compared to the earlier MCAS activation. Within 10 seconds they were experiencing negative 2g and 40 degrees nose down pitch on the FDR, so moving arms may have been impossible. During that time the aft forces on the yoke reached extreme values, and it is probably impossible to pull and trim at the same time. Hope that makes sense.
Originally Posted by
threemiles
The cut-out switches are not on the FDR plot. Whether they turned them back ON is pure speculation.
Not true at all. There is a long period where the trim is stable, and the cutoff switches have clearly been disabled, inhibiting MCAS. This is shown on the FDR. Later there is a sudden uncommanded nose down trim, consistent with MCAS. The only logical way this could have happened is for the switches to have been been enabled. To suggest that this is pure speculation, flies in the facts shown on the FDR.