If the airspeed data was erroneous/unavailable for 50 seconds or so and then became available why the aural "STALL" warning was not continuous since? I think an audible "STALL" and "SINK RATE" would be more than enough to get the crew aware. The question is: why there were no such alarms? Or why it sounded only when the sidestick was pushed forward, supposedly breaking away from the stall, or at least relieving it? Maybe I'm missing something...