HN39
Thanks for your thorough answer. Regarding this spiral dive hypothesis, do you suggest an intended manoeuvre ? I suppose a 1.6 load factor spiral dive would certainly call for a "fasten seat belts" emergency announce, so most of pax and cabin crew would have been strapped ? Or are you thinking of an uncontrolled spiral dive (in this case, the cause for this dive would be as acceptable as anything else for what I called the "initial upset") ?
I may be wrong, but the more I think about it, the more I guess this plane has been initially affected by something huge and totally unexpected, with all unstrapped people being instantly killed or severely injured, and the direction of the plane being radically changed in a few seconds. A subsequent spiral dive followed by a (failed) recovery attempt would fit well in this kind of scenario.