Flat Spin
You are assuming that the "flat" in "flat spin" means that the fuselage is horizontal. That is certainly not the case in a Pitts S2, at least not always, and when my then boss used to demonstrate flat spins at airshows in his Super Chipmunk, (even though the FAA claimed it was impossible in those days) and first tried it in a Lockheed 12; those flat spins were not horizontal either. However, both Pitts and Chipmunk lost altitude at an alarming rate and although I dont remember much about the L-12, I suspect an A330 would too; it was not a falling leaf sort of experience... Therefore, I would suggest it more likely that the aircraft flew into the water at a minimal angle rather than spinning in.