Originally Posted by
DozyWannabe
@JJFFC
Simple. AF's argument is that the stall warning sounded at the same time as the pilots fed in nose-down inputs (i.e the correct way to recover from a stall) on every occasion. They are using this to argue that the stall warning gave a false impression to the pilots that they were doing the wrong thing by putting the nose down.
During the STALL, the Stall Warning was ON for 54 seconds, going OFF at FL350, after which it was OFF and ON, for various short durations 10 times during the rest of the "a/c" descent.
It has been explained on the Tech Log, and the BEA Interim Report is documenting that the STALL Warning has shown two problems.
1. It stopped during the Stall, giving the wrong indication that the Stall condition went away, when there was no action performed to take the "a/c" out of the STALL, but rather the opposite.
2. It started during the Stall, while the PF was in the process of applying actions to take the "a/c" off the STALL, with ND commands, giving the wrong message that the "a/c" enters a STALL.
These two problems contributed to the confusion in the cockpit, during the Phase 3, after the STALL.
By matching up the trace graphics to the best of my ability it appears that this is not the case.
On one occasion, the stall warning comes on at around the same time PF puts in a nose down input, but after then there appears to be no match whatsoever, and in my opinion appears to be in response to the pitch angle of the aircraft (which is stalling and out of control) as opposed to any sidestick input. In fact, if I've lined things up correctly, it appears in a couple of cases that the stall warning stops as nose-down is input, which would reinforce the correct behaviour by the terms that AF are putting forward.
I've seen the graph that you've posted on the Tech Log, and the one on this thread. The one I've seen on the Tech Log the Stall Warning graph was not aligned well, it was pasted towards the left, and thus there was misalignment of the vertical axe (Y) with the PF and PNF stick graphs.
I've commented on the misalignment, but am not sure if you edited it, and re-post.
The BEA report states the correlation, as it was explained it above.
The graphs - this has been mentioned on the Tech Log - that out that the 8 Stall Warnings, 6 are aligned with time intervals with ND commands, and 2 with time intervals with less NU and ND commands The PF stick command graph has not enough resolution to see clearly that the remaining 2 Stall Warnings coincide with NU spikes.
I have no idea why any of the above would be attributed to AF.