bear;
I'm a data guy and gums is right - a detailed analysis isn't wise nor is it possible. I think dissecting the BEA Note word-by-word and looking for subtle meaning between the lines is a mug's game. We'll have a lot more in less than a month and they know that. They'd choose their words carefully of course but eventually it will all be there to examine.
Re your questions:
Re: your last post, what are your thoughts relative to LAW and the STALLSTALL @ a/p drop, and after PF's first control input?
The a/p dropped out due to NCD [No Computed Data - airspeeds]. As a result of the NCD, the flight laws reverted to Alt2 as designed. No control is lost, no squirrelly behaviours lurking, just an airplane with the same flight controls as before. No big deal. Really. Ailerons respond the same way, pitch is gee-driven with "limited feedback and gains." If one is accustomed to the airplane, hand-flying it at FL350 is a non-issue providing one is gentle and makes tiny corrections. The airplane WILL respond aggressively (as it is designed to) if large, swift inputs are commanded. Take it from there.
Had the a/c entered ALAW 1 or 2 at that point? If so, wouldn't the Alert have been somewhat close, (following) the a/p loss alerts?
The Monitoring process of the paired, "Command/Monitor" design of all flight computers provide input to many other computers including the FWC which distributes the messages to the CMC (ACARS) in the manner described in the first BEA Interim Report.
The timings of events are details and may not even be specifically recorded at the moment they occurred, though their occurrence is recorded. As with the ACARS messages when we saw them for the first time in July 2009 or so I don't think we can take very much from the order of failures.
Things were unfolding rapidly and it takes time for other things to catch up.
In part, that's why its important to wait for things to settle down, and, other than maintaining controlled flight by maintaining pitch and power before the failure, see how the loss of airspeed unfolds.
Very little by way of aircraft behaviour or external environmental factors when flying a transport aircraft requires immediate, instant response from the crew. The pilots here could name the few that do require swift, accurate action, and the UAS is not one of them at cruise altitude. A TCAS avoidance event should never be noticed in the back, for example.
Would the AoA have been responsible for the Warning?
The stall warning is AoA-driven as is now known, but as per A33Zab's excellent and very helpful post above, the AoA at which the stall warning triggers is the summation of Tables A & B and where applicable, C. (I don't know what the 2 and 3 digit numbers mean in the Slat-Flap Table in the table below Table A.) Other than what the tables indicate, the airspeed (CAS & Mach) do not have any link to the stall warning system.
If so, could the AoA have been influenced by either UP or DOWN Flow? Could the AoA have been (transient) in either very Low or very High values?
Very momentarily, perhaps, but the variations would be tiny - half a degree, etc. I've accessed the "Alpha Lab." parameters page in the ACMS menu many times and watched the AoA as well as the VRTG and LATG while in turbulence. The AoA varies around a pretty constant reading of 2.3deg NU or so, (>3 would be unusual, in my experience), depending upon weight. There is no evidence of a significant, sustained up/down draft in what has been provided by the BEA. While the aircraft was in unstalled flight, I doubt very much whether low or high values would obtain at all by up/down draft - weather. One minute before the first event, no one was especially excited or concerned about the plan to divert around weather. Not impossible, but unlikely/improbable.
Is there any chance that the a/c could have been in Normal Law long enough for the Alert to have been triggered by greater than AoA 23 degrees? Or, if a DOWN Flow, a negative AoA?
No on both questions. The pitch up did not begin until after the reversion.
If in ALAW 1 or 2, Would the AoA have been indicating legit?
We have to grant that the AoA data from all three sensors was working normally in the three hours before the event. Finding/seeing an abnormality in the data would not be difficult, even given the small changes; such would likely have been mentioned in the BEA Note. On the reversion to Alternate Laws, the flight control laws have nothing to do with the AoA-Stall warning system.
If so, how could it then silence (Cricket, STALL) and allow for a somewhat large increase in PITCH? Also a climb to 380?
Please reference the very fine work done by mm43 - an excellent presentation I think, then in the mind's eye, rotate the airplane about its center, imagine high-speed airflow from left-to-right and imagine what that flow does at the surface of the wing, and how the angles he has drawn change. Not to simplify but to emphasize, airflow around the "interruption" of an aircraft wing into airflow, is a "living" process, always changing, always in motion, always balancing the forces in response to where it is pointed and where it is actually tracking. (That is the value in the FPV on the PFD...used it many times to do steep turns in the sim! - they may have tried it to verify what would have been a "beyond-belief" rate of descent).
Specifically, Pitch and AoA are not linked so a conclusion that the pitch was "higher" does not necessarily link to a higher AoA which had originally triggered the stall warning.
Pull a bit too quickly on the stick even for a second or two and the AoA can go from 2.5deg to 6 very quickly while the pitch remains essentially level as the huge mass (airplane) catches up in another second or two.
High altitude flight is very different than work down lower. As Davies points out and as those who do this work know, the damping effects upon the aircrat of thinner, (at 350, less than a quarter of the density at SL), air are far less effective. He specifically, clearly, cautions that one must be gentle with the aircraft. That hasn't changed in fourty years whether cable-and-pulley or fbw with protections.
At the zenith of the climb, when PITCH 16, and AoA 6, instead of decreasing, could the AoA have actually been increasing to +6?
That's a question which must be answered by the data. We cannot go by how the text is written in the BEA Note - the data's the thing. We know the AoA rapidly ended up at 16deg just after the zenith and increased from there.
There is nothing "new" in any of this. It is standard stuff learned in courses on high altitude flight, weather, aircraft systems and so on as part of the craft. As always there will be nods and disagreements but the general principles hold.