Svarin;
Thanks for your response. Respectfully, I would like to continue challenging your theory as a way of proving-disproving through "finding out". In the end, we may find that it cannot be settled. The theory, engaging and "possible", may still be trying to fit known facts "into the box" as opposed to examining why the PF pitched the aircraft up and continued to do so.
Originally Posted by svarin post #326
Originally Posted by PJ2
was "in control", (do you claim it was the "Master FCPC"?)
Svarin: No I do not. I expect it would have acted upon its sole authority following Normal law and quite possibly its protections, interfering badly with what PRIM1 was doing according to PF orders. Being in Normal while Master was in Alternate 2, it would have deemed its Normal law better than what was asked by Master PRIM (PRIM1), thus resisting it.
Originally Posted by PJ2
Any "partial input/control" by other than the Master FCPC is prevented "by design".
Svarin: Not quite. Especially on elevator control, the need to activate all servos simultaneously under certain conditions make it necessary to cater for dual PRIM outputs onto parallel servos. Such thing is therefore not positively excluded from the design.
Originally Posted by PJ2
The theory must reconcile the comment from the PNF about "Alternate Law"
Svarin: Alternate 2 law was latched by at least Master PRIM1, and likely PRIM3, thus triggering the Alternate law ECAM and PFD effects.
Regardless of how it is put in your theory, in the above responses to my post, it is being claimed that two PRIMs, #1 and #2, are contributing to or
co-sharing control of the aircraft....#2 providing those responses which apply in Normal Law and #1 giving those responses expected in Alternate Law.
The Priority Logic of the EFCS which is located in the FCPCs but independent of the controlling/monitoring functions of the FCPCs
plus PRIM #2's failure to remain in Alternate Law due to a programming error, are, (as
A33Zab has also said about the latter), two very serious flaws emerging independently
and concurrently.
I agree completely with your comment therefore, that this is indeed a "
very strange failure combination, so strange as to put the whole flight controls system out of its designed domain."
On another post...
Originally Posted by svarin post #339
This looks like crossing logics with non-intersecting parameters where a decision cannot be made by logic alone.
How is this sorted out ?
I suggest respectfully that it cannot be "
sorted out" because it has not been established that this is what happened. It remains a theory. One can only "sort out" inconsistencies in theories through a tautology or by broadening the theory to reasonably account for inconsistencies.
If I may, it is claimed that there is a "Master PRIM", but that there is another, working independently which materially affects control of the aircraft. The theory cannot have it both ways. Instead of asking the question of how to sort it out, (see "Byzantine failures" in previous threads), it needs to explain, beyond claiming rogue programming or rare events, why the Priority Logic as thoroughly explained by
A33Zab's substantive posts, and the PRIM2 control in Alternate Law did not fully apply and instead caused a pitch-up of the aircraft in response to a false CAS > VMO + 4kts (where does that indication come from? - it can't be just "spurious"), the evidence for which, it is claimed, is some nose-down inputs during the pitch-up. Remember, the FMGECs supply orders to the FCPCs and the FCSCs and are also monitoring inconsistencies in output.
The Overspeed pitchup is a limited response in Nz Law...+ 0.3g (on top of Nz 1g) and a 22.5deg pitch up IIRC but more importantly, the High Speed Protection Law is overrideable in Alternate Law (specifically, VMO 2 Law) but not in Normal Law until the speed falls below a certain threshold. If it was overrideable as claimed, (reduced climb rate in response to ND stick inputs in the pitch-up), then Normal Law clearly did not apply at that point, so at what point did PRIM 2 stop "interferring" and why?
The other theory about the pitch up was re-introduced by
sensor validation in response to
HN39's question, What caused the pitch-up? I think the AAIB Report, which deals mainly with the TCAS - AIRPROX event, does not explain the AoA response accurately and perhaps even glosses over some characteristics of the A340 (and A330) Alpha response in 2001, which were changed as a result of an ADR/Pitot incident on the A330 in 1996 which also resulted in changes to the stall warning and brought in te notion of returning to Normal Law after a short period of time, (because the aircraft involved in the incident latched in Alternate Law, period). The change in question concerns the Alpha Prot Law which was and is inhibited above M0.53 by the updated FMGEC Standard.