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Old 28th Jul 2011, 17:42
  #835 (permalink)  
PJ2
 
Join Date: Mar 2003
Location: BC
Age: 76
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Takata, I fully concur with your remarks; tomorrow is not going to "solve" this. Expectations that it will are bound to be disappointed because that isn't the way accident investigation works. Reification of this or that pet theory will not be found in this update.

airtren;

Thanks for your comments and question.

Machinbird made a good point a while back in pointing out to me that "doing nothing" isn't the exact response and of course he was right. By the phrase, I was assuming a great deal on the part of the reader. What I meant was, other than maintaining level flight as best one can using pitch and manual thrust settings, (which would be those which existed just prior to the failure), one "does nothing" in terms of climbing/turning/descending etc. Above all else, one stabilizes the aircraft in level flight. There is absolutely NO reason to change anything during a UAS event.

Now, your question is a good one, made even more important by the extensive and wonderfully-intelligent discussions by many here who do know their stuff, concerning the behaviour of the A330 in Normal, Alternates 1 & 2 and Direct Laws, including simulation of same. I have learned both here and in private communications more about the airplane I flew for many years than I ever knew during my time on the airplane. (There is a notion there that I would like to explore, but time, space and a low desire to do so all call for a break at the moment). The airplane flies and works brilliantly; what is being explored here, as takata notes, are the extreme boundaries of flight in a heavy transport, and at the boundaries, (note: not the limits, but the boundaries), of design and engineering. That is why this accident is extremely complex, involving the above and a healthy dose of human factors, ergonomics, warning systems, and so on.

I assumed the airplane was just about as easy to fly in Alternate 1 and 2 and Direct Laws as it was in Normal. I have done this in the simulator many times and I think it is safe to assume that simulator fidelity is high in these regimes, (vice low fidelity in the stall or upset). It was never a problem flying the airplane thus, nor was it like "balancing oneself on the top of a greased flagpole". I understand the roll direct is brisk, but at altitude, one is always gentle and smooth with a heavy machine in thin air.

In direct response to your question, I think one can manually fly this aircraft at high altitude providing one handles it thus. I have learned through discussions on the reduced damping effects of high altitude flight and the physics of mass and trajectory of a heavy machine as well as the notions underpinning an understanding of PIO, that maintaining level pitch and bank attitudes in the circumstances you describe, would be challenging and perhaps even very demanding depending upon the second-by-second series of sidestick inputs over a short period of time. I think one can lose one's SA if one induces PIO, especially in Roll Direct, a factor which I had not truly been aware of until recently. It will be interesting to see how the BEA deals with this notion and phenomenon, if at all.

These points are why this accident will not be close to resolution and understanding in tomorrow's release by the BEA.

Marshal McLuhan once observed, "In the vortex of process, there are no fixed points of view; understanding is never a point of view." I think that may describe an approach to this report and the final report which will yield the best comprehension of what occurred. If one as a point of view, the report will be disappointing and unfulfilling.

I hope this helps airtren; I am enjoying your contributions and am pleased you entered the conversation.
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