Moscow: A preliminary inspection of the black box belonging to the Russian military aircraft that crashed into the Black Sea suggests that pilot error was the accident's most likely cause, a source close to the investigation said.
"The preliminary analysis of the flight recorder has ended and leads to the conclusion that a pilot error was the cause of the accident," Xinhua news agency quoted the source as saying on Tuesday.
The Russian Air Force's three-engine Tu-154 aircraft crashed into the water minutes after taking off from the coastal city of Sochi -- located 1,600 km to the south of Moscow -- killing all 92 passengers on board.
According to Interfax news agency, another source said that preliminary data shows the wing flaps failed and as a result, the plane crashed after losing lift.
A Russian border guard who witnessed the Tu-154's demise said that the plane began to quickly descend towards the sea, instead of gaining altitude.
On board the military plane were 64 members of the Russian Army's prestigious Alexandrov Academic Ensemble of Song and Dance.
Also among the victims were eight crew members, nine journalists, eight members of the Russian armed forces, two civil servants and the head of an influential humanitarian foundation.