Hi,
rudderrudderrat
Because they didn't keep the ND input in for long enough.
They had not diagnosed their problem correctly, and attempted to arrest their ROD with NU side stick inputs.
I'm in complete disagreement with your statement.
This is no need of long ND input fot change the THS deflection.
Any input (up or down) is followed (a response) by a movement of the THS ..up or down (in the flight law they were)
But the BEA note .. tell that the "
THS remained in a
full up position to the end of the event" ...
So despite nose down inputs ..
BEA again:
"At 2 h 12 min 02, the PF said "I don’t have any more indications", and the PNF said "we have no valid indications". At that moment, the thrust levers were in the IDLE detent and the engines’ N1’s were at 55%. Around fifteen seconds later, the PF made pitch-down inputs. In the following moments, the angle of attack decreased, the speeds became valid again and the stall warning sounded again."
So the aircraft was responding to the nose down inputs orders .. but the THS not !
It's something not right there !