Lots of discussion about pitot tubes instantly icing up as an explanation for the airspeed disparities/anomalies? There's a much simpler (Occam's razor) explanation - if you go back to first principles.
” New information provided by sources within Air France suggests, that the ACARS messages of system failures started to arrive at 02:10Z indicating, that the autopilot had disengaged and the fly by wire system had changed to alternate law. Between 02:11Z and 02:13Z a flurry of messages regarding ADIRU and ISIS faults arrived, at 02:13Z PRIM 1 and SEC 1 faults were indicated, at 02:14Z the last message received was an advisory regarding cabin vertical speed. That sequence of messages could not be independently verified.”
On basics it means: the AP disconnects when gets to the limit but the aircraft is already in an unusual attitude, then it reverts to alternative flight control, then this is followed by ISIS and Inertial failures, then PRIM1 + SEC1 computer failures and finally a sudden decrease in cabin pressure (when the aircraft is already divided in parts), multiple electronics failures as the aircraft is disintegrating.
All this happens between 2:10Z and 2:14Z
Looking at the incident described in post 316, we can imagine what would have happened to AF447, upon entering such a "warm pool", if the autopilot had remained engaged - and the incident allowed to develop. Quite simply, wing and nose drop plus yaw (aka autorotation) at a high power setting as the autopilot and autothrust tried to maintain the flight level - despite, due to the warm pool, suddenly being overweight for the environmentals.
It's called coffin corner. Aerodynamic stall and Mach buffet boundaries come together to define the upper edge of the aircraft's flight envelope. Autorotation (aka spinning) at a high power setting is going to have some further complicating ramifications:
a. firstly, engine intakes are going to be blanked and, being already close to their surge margins at that height, at least one engine will stall/surge...... complicating the autorotation with asymmetric thrust (as per the Jefferson City crash of a Pinnacle CRJ200).
b. Autopilot would disconnect and control law would change
c. ACARS transmitted indicated airspeed anomalies between left and right ASI's? In a spin, the F/O's pitot and static ports being on the other side of the airplane (to the captain's), the pitot and static sensed pressures will be in error (and also quite unalike) and so the ADIRU's are going to be initially integrating different air data and therefore calculating different speeds. That ADIRU disagreement will generate faults.
d. The situation at C will be beyond anything the ISIS has ever been programmed to cope with, so a fault message will be generated.
And thus the flow of ACARS messages begins:
Fourteen of those messages, says the Bureau d'Enquetes et d'Analyses, were sent within the space of one minute, from 02:10UTC to 02:11UTC.
This would have been immediately after the spin entry.
Subsequent ACARS messages (until 2:14Z) resulted from the descent into the storm clouds below and the transition into the unstable steepening spiral (G increasing until breakup thresholds were exceeded). The entire process (to breakup/no further messages) took 4 mins.
I'd imagine that, once into a spin, the centripetal(wrong) centrifugal forces on the flight-deck would've precluded any useful action or allowed any thoughts of transmitting a Mayday. The final cabin pressurization warning would've been immediately prior to total electrical power-loss (due to the first hull rupture preceding a general break-up due to the classic high-speed/g-tightening spiral).
Any amplification of this as a probable scenario (from the available ACARS messages)?
Any exceptions as to the likelihood of this exact scenario?
At least it would seem to credibly explain the airspeed discrepancies that otherwise seem to have everybody flummoxed. Not sure if the Airbus simulators could replicate this, but then again we've all seen what happens to airspeed in different types of spins (stable/unstable).... it fluctuates. Once the A330 descended into thicker air the spin would become an unstable spiral with its characteristics quite dependent upon residual thrust, C of G position and flight control trim settings. In the turbulence and in IMC with no functional flight instruments, a destructive break-up would be inevitable.
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edit to change to "centrifugal"