tquehl;
It is extremely hard for me to believe that the aircraft broke up inflight
Yes, I know.
I have been wrestling with experience vice engineering data - the airplane is extremely strong; is the center of a fully-developed ITCZ CuNim cell capable of breaking an airplane? I think it is fully capable of overstressing the structure to the breaking point regardless of what the crew does with the airplane but I am not an engineer so cannot show or discuss the forces involved.
The available evidence (photos of the wreckage collected thus far) indicates that very large sections of the interior cabin structure were ejected/broke loose and were not deformed by collision with or otherwise inhibited in their trajectories by the fuselage structure. That means either very large sections of fuselage were missing in an otherwise somewhat-intact main structure (like the BOAC B707 over Fuji), or a more complete in-flight failure of all major structures.
The alternative of a low-speed ditching has been suggested but if we think about that, that means the aircraft would have had to have been under control until that point - we could expect at least further ACARS messages in such circumstances (assuming electrical power available and the pitot/ADIRU issues resolved somehow - very doubtful but possible).
The alternative of a "flat" spin suggesting a "pancake" impact has also been made, (the theory which has suggested that that is how the VS broke loose - upon impact, "tilting back" and fracturing the rudder structure - I submit that the tail-structure in that area is far more frangible and would do little to no damage to a vertical structure striking it from the top), but such an impact would result in very high 'g' loading so one would expect far more deformation of the larger parts seen in the photographs than is evident.
There is a common aspect to everything seen in the photographs; the structures are all relatively light in comparison to wings/engines/horizontal stabs/landing gear. Perhaps, like Challenger, (and as has been suggested here by various posters before), these lighter parts fell out of the main, heavier structures which had already failed into a number of open sections and continued to fall for many minutes with a comparatively, (and obviously) benign water-impact.
It has also been suggested that the ACARS trace occurred during the initial accident sequence and perhaps bears no relationship to the Air Caraibe incident - again, we must be cautious of hindsight bias while remaining open to the possibility of the more likely events.
I don't know what part of this is my own hindsight bias and which part is reasonable, so criticism of these kinds of notions is most important.
PJ2