Originally Posted by
CONF iture
I would go further than that :
Even releasing the stick would have brought the THS further nose up.
It depends how long for, and what attitude the aircraft was at when the hypothetical stick release happens.
It went all the way back in this case because the elevators were no longer sufficient to maintain the requested attitude as the speed bled off. The THS had moved approximately 5 degrees nose-up at the apogee of the climb. From that point onwards, the stick is held halfway back by the PF for a further 15 seconds, released for about 4 seconds with a small "blip" forward and then slammed against the back stop for an eye-watering 34 seconds. In short, the THS went where it was told to go by the PF. If he'd released the stick prior to the apogee, it would likely have stayed at a max of 5 degrees NU.
Put another way, the pitch command ratio (NU:NEUTRAL:ND) over the 53 seconds following apogee/stall is approximately 49:3:1 in seconds - which is an overwhelming trend towards nose-up.
Now - an interesting sim test would be to try stick-neutral just prior to the apogee, at the apogee and after the apogee (at the point where the PF slams the sick against the back stop) and see what the autotrim system makes of it. I'd be very surprised if the BEA haven't done precisely that, but a second opinion is always useful.