That aircraft was blown out of the sky, IMO. I STILL think those two Iranian dudes with fake passports are the prime suspects.
When it was first found, I read a very convincing piece by an aviation expert who says the piece trails the main flap as a trim tab, something like that. Anyway, his point was that in an intentional ditching at sea, (to cause an intact sinking with no or minimal debris), that trailing flap would be torn off upon impact with the ocean.
I believe, as many do, that the rogue pilot locked out his copilot and flew a planned route to a mid-ocean deep-water ditching, to create the perfect mystery disappearance.
The flap extension (or whatever it’s called) is the piece that would be torn off, and due to its hollow compartmented construction, it would float.
The plane is sitting on a runway somewhere or has been completely disassembled by now. A few parts thrown into the ocean so they can wash up on some distant shore, is not proof of a crash at sea. (IMHO)