Most likely stalled at altitude,causing a flat spin all the way down, impacting flat on it’s belly.
I have been following this crash on airliners.net and some pilots working the investigation in that region have wild data that does not necessarily support a stall. Mainly a very steep and rapid ascent which which is beyond the capability of the pilots to induce, followed by a very rapid descent.
Initial data shows similarities to a crash involving a boeing 707 that was enroute from Athens to Rome in 1974. NTSB concluded a bomb in the aft cargo hold was responsible for the crash based on forensic evidence. After reading the NTSB report for that flight and comparing data, there are eerie similarities.
I bet that’s exactly what happened. No radio because the poor bastards were too busy fighting it all the way down. The people would of had life jackets on if they had time and the correct attitude to try and land on the water.