After the report I have read on the page 22 of this forum, I might have possible explanation of what happened. They said, there was some sudden surge of engine power, pitch up and than it came down. What if they slowed down the aircraft to a point of alfa-floor activation (don't know for what reason, but may be inadvertantly) and the engines at that moment did not spool up evenly? Alpha floor comes on, if you slow down to a critical angle of attack. It automatically gives toga (max power) to both engines. It is supposed to get you out of low energy situation. But if max power comes on at low speed and one engine spools up and the other is slow to spool up, it would be a perfect introduction into a spin (slow and yawing). Of course, all this is just an idea. We still have to wait for the official investigation.