Originally Posted by
ST Dog
The captain didn't do it because of fatigue, it was to look for answers, thinking he's find something the F/O missed. But he wrongly assumed the F/O would continue to counter MCAS like he had been doing. 20-25 seconds later he's pulling harder than the F/O ever did.
(There are still some oddities in the last 40-50 seconds if the trace. Why the split when the F/O took over? Why did the F/O's force drop so much when the captain rejoined him?)
Wasn't aware of this version of the document - or had forgotten it - on Leeham News.
Even without clear units, control column forces seem no trifle, as expected with mistrim, hence the notion of fatigue.
The split between the yokes occurs when one pilots pulls (or push) harder than the other. Posted a drawing of the mechanism long ago.
F/O pull drop : with the aircraft finally doing a bunt, the acceleration goes negative and the pilots are thrown from their seats. If not very tightly restrained, keeping pulling on the yoke might be difficult.