Accident damage patterns
I can see there is confusion on the part of some about the characteristics of the damage on AF447. The process of tearing apart an aircraft in a crash is a complex process but there are some generalities.
If AF447 had stacked into the water on its nose, there would be some deceleration of the bits from the rear of the AC by virtue of whatever columnar stiffness the fuselage provided and they would generally be less damaged than bits from the nose, but there is another factor in play that would increase the average degree of damage. The volume of water receiving the aircraft's energy would be much smaller and thus the average energy per unit volume of water would be higher than for a belly flop. This higher energy density would take longer to dissipate and the bits entrained in this volume of water would smash on each other with more energy and for a longer time and break each other down in size more.
BEA says the aircraft pancaked on its belly and this seems reasonable to me based on the damage pictures I've seen. In a belly flop, the energy is dissipated very quickly over a larger volume of water. Also in a belly flop depending on aircraft touchdown attitude, there will likely be a number of fuselage breaks. In this environment, aircraft wreckage will be larger and more varied with pieces from the bottom of the aircraft compressed and/or torn, and pieces from higher in the aircraft experiencing varying damage depending on what is in the immediate vicinity. From the number of large parts, it is clear that this was a low energy impact (for a jet).
In the case of the vertical stabilizer, it is pretty clear that the aircraft structure below it was pretty fractured when it commenced it's independent flight.
And why did it peel off forwards? AF447 probably hit with somewhere around 35 to 40 degrees AOA. Since it was basically in a level attitude, that gives a forward speed over 100 knots relative to the water.
Now this is a "professional" opinion from one who has participated in a few military accident investigations involving jet aircraft impacting both over land and over water and I could be really wrong in some of the details I've postulated. I hope they find the wreckage and settle these details.
From the pictures I've seen of the AF447 wreckage, I don't think anything from around the THS has been found that would indicate its trimmed position. I'm betting it was trimmed full nose up. Does anyone have any info that would bear on this detail?