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Old Carthusian,
Thanks for the clarification. I'll reply to your points out-of-order as you introduced an important point later in your reply:
Originally Posted by Old Carthusian
I understand that you would like to avoid the fact that this is a crew issue
In that case, unfortunately you misunderstand me - I'm not trying to avoid anything. I don't know how much clearer I could be about my views on this, than the last 2 paragraphs of my previous reply to you. I'll try one more time...
The crew clearly made mistakes (as you have said); many of the exact causes for those mistakes we don't (and never will) know
for sure (as we can't ask what they thought at the time) although I sincerely hope that the BEA HF group can add a useful interpretation (i.e. educated guess) of the limited available data, in the final report.
However I believe that simply saying "this is a crew issue" and not looking deeper for
likely causes of incorrect crew behaviour, and then
fixing those causes, would be doing a disservice in trying to prevent another tragedy. One of the areas which seems relevant to me, and where we have evidence of other crew behaviour for comparison with AF447, is in the area of UAS recognition, and that's where I have been specifically focussing in my recent comments, when this subject recently re-surfaced.
Of course UAS is not the whole story for AF447, but UAS is where things started to go wrong for them (i.e. they responded with a zoom climb instead of flying pitch & power), so IMHO it deserves some focus. In the past, several professionals here have kindly contributed that their airlines are improving training of high-altitude UAS. But why limit the improvements to training, when the aircraft could also give a less obfuscated indication of UAS? Don't we want the pilots to receive clear warnings, to encourage the recognition of UAS and hence increase the liklihood that they would then follow the UAS procedure?
Originally Posted by Old Carthusian
To clarify my rather hasty response - the point I am trying to make is that a change in the interface is not necessarily going to result in a future avoidance of this kind of accident.
Very true - I can't (and won't attempt to) prove that a specific UAS warning will result in a future avoidance, and you can't prove the opposite.
However, on balance, the widespread problems shown by the BEA analysis of those 13 UAS events, make
me believe that this is an area where there is a systemic problem, and since the PF was doing his "zoom climb" instead of following the UAS procedure, then if he had followed that UAS procedure instead, we may not be having this discussion at all.
Originally Posted by Old Carthusian
It is rather a measure which may well be useful but cannot take the place of training, CRM, using SOPs and a proper culture in the airline.
I completely agree with you (I bet you never thought I'd say that
). All those things are also needed. My point is (as Organfreak and RR_NDB have also said), why not try to reduce or remove all relevant holes in the swiss cheese? Even you have listed multiple topics in your comment above - so we're agreed that this is not a "fix one thing and it'll never happen again" accident, therefore why stop at the obvious human factors? The man/machine interface needs to be designed to communicate clearly with humans who are having a bad day, or just back from their holidays, or in the low part of their circadian rhythm, or ... All pilots are human, even the best.
Originally Posted by Old Carthusian
If you recall the crew of AF447 ignored the stall warning - what guarantee do you have that they would have paid any attention to a UAS warning?
That's a very interesting topic, so I'll tell you my current hypothesis about why
I think they (especially the PF) ignored the stall warning in AF447 (dysfunctional CRM may have prevented the PNF from voicing his opinion, even if he didn't want to ignore the stall warning). But first, you are asking for a guarantee - that's unreasonable.
I could ask you for a guarantee that they
wouldn't pay attention to a UAS warning, but I won't do that because it's an unreasonable thing for me to do and it's impossible for you to guarantee that either. So let's not ask for guarantees and instead be open-minded to possible
improvements, OK?
My current hypothesis is that the UAS situation was not recognised as being specifically that (especially not by the PF; I'm unsure about the PNF), and instead they believed they had a multiple instrumentation problem which needed to be diagnosed from square one - as well as the PF having to hand-fly at high altitude in turbulance and Alt2. From that, misinterpretation of the starting point, they couldn't make sense of the different (and varying) IAS readings as relating to a single failed component (because there was no single failed component!), and kept trying to understand their readings, which then became difficult to fit onto a mental model once stalled (even though all 3 were consistent eventually), as they don't train for being fully stalled.
Therefore my hypothesis is that the stall warning was being deliberately ignored as they (especially PF) thought it was a malfunction, as part of the same instrumentation problem which was affecting the IAS.
If they hadn't "gone off at a tangent" trying to diagnose what was a temporary UAS, and had instead received a clear warning from the aircraft like "This is a UAS situation, all my pitot probe pressures are different so I have to disconnect the AP - recommend you fly pitch & power which for this alt is X/Y", then would the zoom climb and all the subsequent problems still have happened? Neither of us know the answer, but
anything which stopped that zoom climb from being done would have been an improvement over what actually happened.
So that's my current hypothesis. I could be wrong (partly or completely) - we'll never know for sure either way, although I'm happy to be guided by the professionals here and the HF part in the final BEA report.
Originally Posted by Old Carthusian
Now to touch on the point of the other accidents [I think you mean the other 13 UAS events in the BEA report??] - all resulted in recovery and a return to normal flight. The outcome is the important thing here not necessarily the process.
That's clearly your view, as you've said it several times. I disagree and instead believe that the process is at least as important as the outcome. After all, how many of those other pilots are just "a bad day" away from mis-identifying a UAS, and doing something else which
is dangerous? Unless you present some compelling evidence that
not following the UAS procedure is safer than following it, then I don't see me changing my view, although I'm happy to seriously consider whatever is causing you to dismiss the importance of following the UAS procedure.
Originally Posted by Old Carthusian
But even if a warning system is devised this is not a rapid process - it needs careful consideration and testing so that it can be properly deployed.
I completely agree - but I don't see those as reasons not to start the ball rolling on investigating this, especially as other problems which you have highlighted (e.g. airline culture) may take even longer to improve.