Originally Posted by
Ian W
One of the aspects I expect the BEA Human Factors investigators to look at is the cognitive workload that the ECAM and failure messages put on the pilots. Especially the aspect of overloading particular cognitive channels. Perhaps every potential emergency scenario should be subject to what is called a 'cognitive walk-through' that actually assesses the cognitive loads and identifies likely overloads.
Hi Ian,
I think you're definitely on to something with your second and third sentences there, but I'd like to see what you think about an alternative theory/explanation that I posted on the R&N thread. The particular links are below.
http://www.pprune.org/rumours-news/4...ml#post6665388 (1)
http://www.pprune.org/rumours-news/4...ml#post6665478 (2)
http://www.pprune.org/rumours-news/4...ml#post6665527 (3)
The meat of the theory is in the third one, but the first two provide background notes as I was working through it. The first in particular lists data points in the interim report that I hadn't put together before.
In a nutshell, I'm not convinced that the ECAM messages provided that much of a distraction, except initially - the PNF calls out the most important ones at any rate. Disregard the PF for now, and focus on the PNF - he's clearly getting jumpy as soon as the PF takes manual control, but because of the informal handover, he doesn't know his boundaries of authority, so he summons the Captain to clarify. The stall warning goes off shortly afterwards and after approx. 50 seconds of letting the PF handle the aircraft, the PNF has had enough and takes control. The inputs he makes are correct, but not enough - a couple of seconds later the PF takes control back unannounced (i.e the PNF still thinks he has control) and starts pulling the nose up again. A second or two after that, the stall warning stops, with both the PNF and the PF thinking they have control. The PNF's inputs were correct (lower the nose, stabilise roll), but again - not enough. Did he think he had resolved the problem with the end of stall warning? Complicating matters even further is the arrival of the Captain - 2 seconds before the SW stops, when the PNF presumably turns round to talk to him, and as such he loses all focus on the flight controls and the PF is still pulling back.
I'm not sure if human/machine cognitive overload is the problem here so much as the level of pressure and stress on the PNF. For all my opinion's worth as a layman with an interest, could it be the human/human interface that is causing the issue?