From 2 h 10 min 05 , the autopilot then auto-thrust disengaged and the PF said "I have the controls". The airplane began to roll to the right and the PF made a left nose-up input. The stall warning sounded twice in a row. The recorded parameters show a sharp fall from about 275 kt to 60 kt in the speed displayed on the left primary flight display (PFD), then a few moments later in the speed displayed on the integrated standby instrument system (ISIS).
...
Note 2: Autopilot and auto-thrust remained disengaged for the rest of the flight.
At 2 h 10 min 16, the PNF said "so, we’ve lost the speeds" then "alternate law […]".
All of this is consistent with loss of speed information to the computers (and the flight deck instruments) due to iced-up pitot tubes, and it would appear that the PNF correctly diagnosed this in a little over 10 seconds. The plethora of warnings came after whatever caused the pitch-up and stall condition.
Wouldn't a "left nose up" command without any change in thrust cause airspeed to decrease?
For a stall warning to sound wouldn't the airspeed signal still need to be valid?
If with no increase in thrust and a nose up input after a stall warning sound along with a climb rate of up to 7000 ft/m cause the airspeed to rapidly fall?
I believe the correct position for the horse is in front of the cart not behind it.