The copilots had received no high altitude training for the "Unreliable IAS" procedure and manual aircraft handling
BEA
I am only repeating what has already been discussed but the thread is so long,its hard to find the fundamentals and keep your bearings.AeroCaraibe suffered an almost identical incident(s) just prior to AF447 and a lengthy report was issued.Same Aircraft,same pitots,same icing encounter,same language.Why then was it not disseminated,digested and trained on?
The key line in the AeroCaraibe report(French language only) says:
"En effet,le 'PF' est intimement persuade que les deux alarmes 'STALL' sont inappropriees.C'est volontairement qu'il ne tient pas compte de la phrase 'RESPECT STALL WARNING AND DISREGARD RISK OF UNDUE STALL WARNING STATUS MESSAGE IF DISPLAYED ON ECAM."
The AeroCaraibe pilot used a KNOWLEDGE-BASED response to loss of airpseed and spurious STALL warning associated with pitot icing.Fly pitch and power,2.5 deg ANU and 82% N1.My question is that even if the AF PF was unable to disbelieve his instruments and ignore any spurious warning,why did he pitch the aircraft to 10deg+ ANU?At FL350???Would not the instinct be to fly TOGA and 0-2.5 ANU pitch?And then find himself in overspeed after the icing clears(only 50 seconds)?This is very confusing.Someone said that FBW pilots apply TOGA and full ANU on the stick in response to stall.Now he acknowledges ALT LAW(ie.a/c can stall unprotected..is that right?) yet goes for 10+ANU pitch at 35000 feet?
Pitot-static anomalies are not easy for pilots;you have to ignore your instruments affected by the blocked sensor and maintain concentration on pitch/power through a cacophony of aural/visual alerts,some valid,some not.Experienced crews have been flummoxed by conflicting information as seen in Aeroperu and Birgenair.Use a rule-based response at your own peril.But those crews did exactly that.And there was a Captain sitting in the left seat on both flights,although an umbrella of suspicion is certainly cast over the quality of the Birgenair crew(he continued the takeoff with an AS disagree).
The two Airbus anomalies here(THS stuck at 13ANU and stall inhibited below 60),although contentious,should never ever have come into play.Lets assume that we cant expect two co-pilots to apply a KNOWLEDGE-BASED response to a high altitude unreliable airspeed event at night over the Atlantic.They are fooled by the conflicting information despite the fact that they knew they were flying at M.8 just moments prior.They now believe they're in a stall.They believe whats presented in front of them.Then there should not have been any ANU pitch command and hence no auto trim to 13 degrees,no speed(real) decay and no possibility whatsoever of stall inhibit.They should have found themsleves in an overspeed condition after the pitot unblocked which may/may not have led to inflight break-up.This would have been plausible,even forgiveable.All they had to do was do what the AeroCaraibe crew did.Set 81% N1 and put the nose just above the horizon.It was flying before with those settings,it will continue to do so.