Originally Posted by
PickyPerkins
Can someone please explain to me how to following can be possible:
The report says that during the flight previous to the accident flight, "The PIC moved the STAB TRIM switches to CUT OUT and the SIC continued the flight with manual trim without auto-pilot until the end of the flight." That’s clear enough.
Now look at the FDR record for the manual and automatic trim input, and the actual trim position.
The actual trim position increases without any manual or automatic trim increase (in the upward direction) with the CUT OUT in operation. The only automatic and manual inputs are down, but the trim position moves up. Or am I reading everything backwards?
The FDR doesn't record manual trim input if its you moving the trim wheel by hand. What it records are trim switch inputs.
What I think you are seeing is the stab moving in response to the wheel, not the "manual trim" switch.
It's down to the exact meaning of "manual" trim - a human manually commanding the trim motor through a switch, or a human manually applying physical effort himself to the trim wheel to move the stab.