Hmm so is the answer more automation ? should the GPS be added to the logic with airspeed disagree ?
Could the RAT be deployed as another possible speed indicator(assuming it has some sort of RPM display)? or would if just turn into a large block of ice, in this case with the freezing rain etc.
Unlike the Boeing, the FMC on the 330 gives you (solely) GPS derived Altitude and groundspeed, Boeing only gives Altitude (777). In amongst all the goings on, why didn't they look at the GPS derived figures on the FMC? The Alt would have been counting down rapidly and the groundspeed would have shown 80ish knots.
Would have solved the 'are we climbing or descending?' questions the PF was asking........................