This is all very very odd to say the least. We can only sit and make educated guesses, but the answer to this must come via the flight recorder, which although must be lying at the ocean bed, is still sending locator beacon beeps, and ought to be picked up by the submarines sniffing around down below.
The loss of life still hurts whatever the cause, and lessons must be learnt if it was a preventable snag.

Well said, Doc. There have been instances where certain classes of airliners have shown the development of cracks at fatigue points well before their design limits. This has resulted in lost tail sections, wings, etc. It is an expensive campaign to undergo in order to retrieve a black box buried under tons of water, but the result may be in safer planes and no further loss of life.

Let's just hope that the treasure isn't below the depth that even our deep submersibles can bring it up. I don't know what sort of manipulator arms they have on some of those things, but they may have to cut sections of plane away in order to reach the black box. Either that or figure a way to float whole sections to the surface. (I think they'd like to have the entire plane though so they can reconstruct it.) What a science that must be.

I'm sure...in time...we'll be able to find out what happened to the Air France flight. The unfortunate thing is that all the wreckage is spread out through something akin to the Andes mountains, underwater.