Originally Posted by
DaveReidUK
You are assuming that "The First-Officer has replied that the trim was not working" means that he attempted unsuccessfully to use the electric trim switches.
It could equally have been him just confirming that (as you rightly say) just over a minute previously both pilots had agreed to disable the stab trim (05:40:35), given that it was followed immediately by asking "if he could try it manually". In other words, the electric trim switches obviously weren't going to work, and there wouldn't have been any point in trying them.
Dave, I am ready to bet that the captain question came after he unsuccessfully tried to operate his trim thumb switches and that he actually asked the FO to check if the switches on his side were also not working.
Further, I can't imagine that the FO answers "the trim is not working" without giving it a try.
Besides, the electric wiring schematics are plain and clear ; the pedestal cutout switches disconnect the trim thumb switches from the 28V DC coming from the CB panel and the probe line running from the switches to the DFDAU can no longer record a variation of potential.
So, any attempt to operate these trim rockers after switching off the cutout could not have been recorded, as per the schematics.