Rescuers carry the body of a victim of Russian Defense Ministry's Tu-154 crash in the Black Sea coast off Sochi, Russia, Dec. 25, 2016. (Xinhua/Sputnik)

MOSCOW, May 31 (Xinhua) -- Mistakes made by the pilot may cause the crash of Russia's Tu-154 aircraft in the Black Sea in December 2016, the Russian Defense Ministry said Wednesday following the conclusion of an investigation.

The probe found that the pilot of the Russian military plane could lose his spatial orientation or situational awareness and made a wrong decision when operating the aircraft, said the ministry.

Investigators found no violation of rules concerning fueling, passenger seating or cargo loading, and the Tu-154 was not affected by external factors either.

On December 25, 2016, the Tu-154 en route from Moscow to Syria crashed in the Black Sea shortly after it refueled and took off from Russia's southern city of Sochi.

The plane was carrying 92 people, including musicians of the Alexandrov Ensemble, servicemen, journalists and crew members. None of them survived the tragedy.