PPRuNe Forums - View Single Post - 4th Aug 2018 Junkers JU52 crashed in Switzerland
Old 13th Aug 2018, 16:40
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hans brinker
 
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Originally Posted by meleagertoo
It never ceases to amaze me that even after 30+ years of human factors training in which human fallibility is so closely examined, additional to decades of global accident statistics that show conclusively that by far the biggest single cause of accidents is broadly dscribed as "pilot error" that so many pople are so reluctant to accept the likelyhood that this accident was simply what it appears to be. Mishandling.
There have been dozens of accidents reported in this forum over the years that have attracted the same old automatic responses, "A 60 year old commerecial pilot would never do that!", "He was an ex military pilot, he'd never make such a basic error", "I knew him and I know he'd never make such a mistake" "he was a brilliant pilot and he'd never -"etc.etc.etc. But every time he did, time and again it turns out that's exactly what they did. I realise it's difficult to accept that even such experienced pilots as this can make such a basic error but experience, history and statistics prove that they do, and regularly. Sure, HF applies here too, acceptance of the ability of experienced pilots to make very basic errors relies on our acceptance of our own fallibility, something none of us like to admit to. Thrashing around trying to invent ever more ulikely scenarios (elevator trim failure was one) when a heavily loaded, underpowered vintage aircraft tries to make a downwind turn in a mountain valley just below a ridge at high density altitude and falls inverted from the sky suggests to me that the lessons of HF are still not as ingrained as they might be, though I recognise that there are a lot of expert spotters/spectators etc here vs. pilots who have actually studied that subject. Sad as it seems it appears that these guys got themselves too far into a narrowing hole and tried just a bit too hard to turn out of it, and got bitten by 1930's stall habits. What seems more important here is not so much the what as the why?

There has been considerable discussion about the stall characteristics (esp. power on) of the DC3/C47 following the CAF's recent accident in which many have attested to that type's viscious stall habits. Tante Ju was from a design era pre C47 and would very likely behave in much the same abrupt manner in an aggravated power-on stall. We saw the Australian Mallard make a simiar manoeuvre with similar results. Yes, of course there's a tiny possibility that the inside knurled flange-bracket went "ping" but all the evidence points elsewhere, and whatsmore to the same place. But that's playing double jeopardy, isn't it? At the very point in a flight where every aviator says "Bloody hell, they're really asking for trouble doing that" something completely unexpected and invisible yet critical chooses that very instant to break. It isn't really a credible scenario. (viz the Shoreham accident. Page after page of fanciful speculative failures when all the time the duck was sitting there patiently quacking away)

Guys, though it isn't yet proven (and never will be as they 99.9% for certain won't find anything significant in the mechanical investigation) this case has all the attributes of the duck analogy. Looks like, sounds like, swims like. Is.

I think we'd sometimes do better to recognise and accept the weight of the obvious in reaching our local (as opposed to the investigators') conclusion rather than trying to invent fanciful "balancing" arguments where no shred of evidence nor requirement for them for them exists.

We have had a report (my previous post somewhere above) that on a previous flight the aircraft was apparently flown in a more "sporting" manner than the pax liked such that the pilots had to be asked to tone it down and though that report is anecdotal and a one-off (so far) it may well indicate an operational style that had developed. I too find it hard to believe that professional pilots would throw pax around so much they got sick and had tp be told to knock it off but apparently they did. If that does prove to be the case one can only wonder whether it was a one-off or not, or had other less than prudent habits attended the operation not just in flying but in the field of performance and loading perhaps? If so it wouldn't be the first time professional pilots, removed from the straitjacket of airline ops found themselves in a relaxed little fun operation where they could cut loose a bit. And came to grief because of it. After all, that's just human nature (factors).

That is where the bulk of the investigation will centre I suspect.

Great post, sadly totally made irrelevant by the words " downwind turn". There are downdrafts downwind of mountain ridges, but there is no such thing as a downwind turn.
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