Originally Posted by
DaveReidUK
But your proposition requires that
...
b) simultaneously there was an unrelated software/processor issue that prevented the pilots' trim inputs from being recorded on the FDR
I'm short on time to find the post, but there was compelling circumstantial evidence presented in this thread a couple of days ago that pilot trim inputs are sent to the FDR from the stab trim motor (whereas mcas/speed trim inputs are sent from the trim computer). In such a case, it is in fact very probable that failed pilot trim inputs will not be recorded by the FDR.