Problem is that they appear not to have kept them there and in order to apply full nose down stick I suspect the TC (or HP) took his hand off the throttles to use both hands - and they closed.
When I said "
all they had to do", that's what I meant. That is, they didn't need to "apply full nose down stick".
Are you saying you flew 4 stick shake recoveries with full power applied - and the A/P coped? You never got more that 25 deg nose up?
I'm saying exactly that. Set up on the ILS, autopilot following the glide path, autothrottle disconnected and throttle at idle. Full flap and gear, autopilot trims aft as the aircraft slows to stick shake, wait 2 seconds to make it more "realistic" then simply advance the thrust.
Speed increases slowly at first, with the high drag, autopilot maintains the descent on the glide path. Speed increases back to Vref, as the autopilot re-trims. If you wish , you could simply reduce the thrust and continue the approach from there.
Obviously you are guarding the controls, in case the autopilot disconnects under the trim load.