yoko1, # 676
The FDR printout suggests that the electric trim was operable at that time, however there is no evidence that the tail moved - possibly too short a time scale. Thus probability enters the debate; more accurately we don’t know.
Reconsider the EASA question about lack of electric trim throughout the flight envelope (NG). The Boeing response indicated that this was a design intention to minimise the risk of trim runaway, thus use manual wheel. This has not been confirmed or refuted; again we don’t know.
Thus either the elect switch indication on the FDR remains operable, but by design not the trim motor; or whether the inhibition applies in both tail directions. Alternatively if the trim was operable, then the motor was unable to move the tail due to an accumulation of adverse forces, not identified in certification or in the EASA query due to extreme tail position, e.g. large tail nose-down plus elevator nose-up, which as referenced in Borns blog as hydraulic jack stall; and an indication of the magnitude of forces involved.
A further speculative view is of an adverse interaction between manual trim wheel from one pilot and elect trim from the other; what is the priority re clutching mechanism; does manual input de-clutch the electric motor ?