IIRC, the pitot-static system failed due to icing. The computer saw a speed mismatch and shut down.
With a plugged pitot port, the static was still open, and caused the altimeter to show a climb.
The (relatively low time ) flight crew raised the nose and reduced power settings. Plane started to descend, but altimeter and ROC indicators indicated it was still climbing. Further reduction in power.....etc....till splash. Went into a falling leaf deep stall.
The AF pilots are trained that the computer can take care of everything. They aren’t taught analog flying (like when you should break the glass on one of your instruments).
It has been about 6 months since seeing this stuff in detail, but basically the flight crew were flying by erroneous flight instruments when they should have set power and pitch at the settings called for in the manual when computer and AS indicators are lost, a known problem in this aircraft.
“With a plugged pitot port, the static was still open, and caused the altimeter to show a climb.”
Altimeters don’t use the pitot. Airspeed indicators do.