Svarin;
Thank you for the clear explanations and responses.
I think I have a better feel for what you are saying.
First, you say, "It is however unfortunate that ADR2 data and associated RHS airspeed was not recorded on FDR..." We cannot say beyond what the BEA has said, what is and is not recorded but we cannot conclude that because the Airspeed to PFD2 is not recorded that the balance of ADR2's output parameters are not recorded. We may optimistically wait and see. The QAR was on the large electronics bay called "800VU" which was brought to the surface. Among the FCPCs, FCSCs, FMGECs and so on is the DFDAU/FDIMU and QAR recording unit. We can hope for the best. Also, there may be some information which can be retrieved from the EEPROMs of these various units - we just don't know yet.
On your theory, please allow me to re-phrase to see if I get it: - You are claiming that one PRIM remained in Normal Law due to a rare timing and rogue programming issue while two others reverted to Alternate Law, ("All three PRIMs are 99.9999% of the time in full agreement. Not this time."), and that PRIM2 which "remained in Normal Law", ("At 02:10:16, the pitch-up sequence and "zoom-climb" happened with (according to my research and "flimsy theory") PRIM1 & PRIM3 in Alternate 2 and PRIM2 in Normal."), was "in control", (do you claim it was the "Master FCPC"?), and pitched the aircraft up in a response to a false high speed, (High Speed Law) and it is this, not the side stick being pulled back, which led to the stall?
I understand that you are claiming this even though a different PRIM which was in Alternate Law, was also sending orders to the flight controls, ("Occam's try on these hypotheses is the triggering of an undesired normal law (full authority) overspeed protection by PRIM2 only which uses erroneous airspeed data after having unexpectedly returned to Normal law.
Further, might you be claiming that the reason that the Stall warning functioned "as designed" is because at least one PRIM was in Alternate Law?
I welcome a correction to my understanding but there are problems with the theory.
Much of this is beyond the limits of my own knowledge of the airplane but I can't imagine a flight crew permitting such autoflight behaviour without resisting it by pushing against the pitch-up because anyone who flies these aircraft knows what's about to occur next if the pitch up is permitted to continue. In Alternate Law the pilot can resist the pitch up due to high speed protection; in Normal Law this is resisted until the overspeed no longer exists.
The BEA states that the pitch-up was caused by a side-stick being pulled back. We have good reason to take that at face value until the next Interim Report because at some point we're going to have some actual data to examine and the BEA know it.
There is always the possibility of other explanations but the burden of coherence rests upon the proposer. If I understand what I have read, the EFCS Priority Logic ensures the operation of a Master PRIM by rejecting FCPCs/FCSCs which have failed their BITE test.
Any "partial input/control" by other than the Master FCPC is prevented "by design". And if "shared control" actually occurs between PRIMs, (one in Normal, two in Alternate), then there is a second problem beyond the fault in one of the PRIMs which returned it to Normal Law and that is the Priority Law which is permitting one PRIM in Normal Law and one or two PRIM(s) in Alternate Law to in some way, both send orders to the flight controls.
I think such a twin failure is highly improbable, especially in the face of the available information.
The theory must reconcile the comment from the PNF about "Alternate Law", (but not the AP disconnection), and the Stall warning which would not have occurred in Normal Law (as observed by HN39). As stated, while the pilots cannot counter a pitch-up order in an overspeed response in Normal Law, they can in Alternate (VMO2) Law. Instead, the side stick was almost always pulled back.
I think we need to re-focus on why the side stick was pulled back after a stall warning and why it was held fully back for thirty seconds while the aircraft was on the way down at >10,000fpm.
A shift in thinking is not intended to focus on the crew. Most here on the thread know by now that such events do not occur in a vacuum and instead have antecedents long before the actual event. It is up to the investigative body to determine how and why these pathways and factors came together.
The point has been made many times and has again recently...how are we to deal with the #1 cause of transport accidents including fatal accidents: Loss of Control?
What is it about the thousands of crews who fly these aircraft, wracking up millions upon millions of hours and miles uneventfully, that is absent in a few, extremely rare accident?
Leaving aside formal accident reports, (where accident reports have been done and made available...), what do we intuitively know for example about the Airblue A321 CFIT accident at Islamabad, the Afrikiyah A330 LOC accident at Tripoli, the Gulfair A320 LOC accident at Bahrain, the Armavia A320 LOC go-around accident at Sochi and the XL Airways A320 at Perpignan, that can help us place the causes of LOC into perspective and decide what way to go, even if "on the way to somewhere else"? Is it really merely the loss of flying skills or a psychological passiveness, a "non-involvement" with the machine, or is this just a training issue?
There are a number of papers available in this discussion. Some use mathematics which are beyond all readers except specialists but some authors such as Perrow, Reason, Dekker, Helmreich, are very accessible as most here will know.
My suggestion is a broadening of focus in the face of the signficant breadth of expertise on this and the previous threads. I do not believe that the answers to our questions about this accident lie in a detailed comprehension and tracing of the EFCS even though such may be involved in understanding what the crew saw and how they responded. The question is how and why so many transport aircraft accidents have resulted from a LOC followed by stalling the aircraft.