[cmurf]

I'd say the improper input was the most direct factor, as it was responsible for the stall condition all the way into the ocean.

But there are multiple major factors leading up to that, including the lack of high altitude training in direct law, and that the simulator didn't exactly simulate high altitude stalls, and that the stall warning stopped when the angle of attack was beyond the sensor limit. All of these things are major and the final report really sank a lot of blame on Airbus and Air France as well as pilot startle effect basically stopping their brains from working the problem. The senior pilot who arrived didn't have that, and quickly figured out the source of the problem but by then it was too late, not enough altitude to recover.