Engine Stall or Not?
takata & sensor_validation
Relative to your questions regarding engine stalling, an engine in a test cell or on the ground without any forward motion behaves in a normal manner as it is sucking air in through the nacelle inlet in a normal manner. However, an engine in the air at high altitude dropping in a somewhat flat plane at some point will stall due to significant inlet distortion, blocking normal airflow. I would think there is a reasonable probability that some of the descent from 35k feet would be recorded, but the total descent (near the end) may not be. There is a possibility the descent had two vertical velocities, a lesser velocity to begin with and a much higher velocity at some point nearer to the sea.
There has be little information at this point about the engines other than what the BEA stated, "The engines were operating normally." However, there is much more information available, real time transmission of engine data back to the airline and probably GE.
There has been mention of searching for the engine electronic controls, but as they are typically mounted on the side of the fan casing and given the catastrophic damage observed on the one photographed engine, it is doubtful they survived.
I have wondered what the shape of the other engine might be in that the plane apparently hit the water with one wing lower than the other according to the BEA. Have we seen the worst damaged engine or are they both the same?