Look at the graph in the post #104. I think there is some answer. They lost an
engine, but managed to climb to 1300 feet in one minute. That seem to be an excessive climb rate. It seems some quite excessive pitch for being on one engine. It seems the speed for single engine was not taken care off. I am not sure, what is the single engine climb rate in an ATR. But 1300 fpm seem to be high. They went below the safe speed and it goes downhill from there. Of course it is just a theory. Who knows, what else could cause all this. But if it was not a control difficulty problem, than it seems to be overcontrolled.
Sad day.