I agree in spirit, 'Hooker, that hers was the final mistake in the chain of events with yanking the flaps. However, at the end of the day, I don't think that's what killed them. I'm pretty sure they were done when he got the pusher, sadly enough.
It almost sounds like if they had just added power, left the configuration alone and let the pusher shove the nose down that the plane would have kept flying. I haven't looked at the specifics all that closely so my opinion could be incorrect.
The problem was their low altitude. At 2,500 AGL I don't think I'd have let the pusher shove the nose FULL over, either. Probably would have mashed the disconnect about the time I was passing through nose-level, rather than let the thing start descending at 4,000-6,000 fpm with 10-12 degrees nose-down (which is about what the pusher will push to - seen it in the sim on other Bombardier products doing high altitude stall recovery after 3701 at PCL).
Once he got the pusher, he had a very narrow window of recovery. If you let the pusher activate fully and wait for it to stop pushing, you hit the ground in 20 seconds unless you override it sometime before you hit and pull it out, hopefully with enough airspeed to fly out,,, or,,,
You override the pusher at 2-3 degrees nose-up (not 20) and hope it flies out of the stall as you're losing 1,500-2,000 fpm and have about 40-50 seconds before impact for the plane to get enough airspeed to level out.
At that altitude, you'd better be Chuck Yeager when the pusher actuates. What was that someone posted earlier about "experience hopefully keeps us out of situations where we are called upon to demonstrate exceptional flying skills"...?
