Why did the Belarus Air Force Su-27 crash at Radom Airshow ?

On August 30th, 2009 a Belarus Air Force two-seat Su-27 crashed at 11H17 GMT while performing at Radom Air Force Base international Airshow (Poland). Both pilots Alexandr Marfitski and Alexandr Jouravlevitch were killed. According to www.strizhi.ru these high rank officers were some of the most experienced Su-27 Flanker pilots in the Belarus Air Force. Alexandr Jouravlevitch was the 61st IAP Commander and Alexandr Marfitski was one of the Belarus Air Defense Staff Commanders.

Watching a video on that display ending with the dramatic crash posted on www.liveleak.com/view , I found clear details on points that remained shrouded with misteries untill today. Where these guys experienced enough at displaying a Su-27 ? How many rehearsals did they perform before the airshow in Poland ? Many experienced guys have crashed with simple loops that were executed too low. They simply did not check their altimeter.

But the Radom crash seems to be due to other reasons, that are not pilot failures or mistakes. Watching the video you can see the aircraft loosing altitude and power and not recovering. It is just disapperaing like a falling stone behind trees. Maybe both pilots attempted to eject, but clearly things happen too fast so that they could havetime to... Surely at least one engine has stopped working at that moment, and though official results of the enquiries may not be publicly released, the technical failure in the airplane is now clear to me.