Pilot error after a simple tech failure, this has been done to death.
What is far more interesting is why two supposedly competent pilots were unable to recognise that 10 degrees nose up and 10000ft per min descent rate is a stall. The Captain realised as soon as he entered the flight deck but by then there was insufficient height to recover, hence his comment “we’re dead”.
If only they’d initiated the airspeed unreliable checklist, or performed an FNC or simply set 2.5 degrees pitch and 90% N1.
Ultimately pilots don’t make mistakes on purpose which begs questions of their training and attitude.
LD