The Mi-8 helicopter that crashed in the Yamal peninsula was running out of fuel.
According to the Interstate Aviation Committee (IAC), the helicopter was to make a stopover for refueling on the way.
Bad weather prevented the refueling at the Rotor-40 site. At 14.30 the crew told air traffic controllers the estimated time of arrival at Urengoi airport was 15.10, TASS reports.
The helicopter was flying at a registered speed of 220-250 kilometers.
"One hour 21 minutes after takeoff the instruments signaled that the amount of fuel left in the tanks was minimal. Four minutes later the altitude and speed of flight fell considerably," the IAC said.
During the next 14 minutes the helicopter’s altitude, speed and course changed sharply many times.
The helicopter hit the ground at 15.08. The helicopter’s engines kept running till the last moment.
The Mi-8 helicopter crash landing 80 kilometers to the north-west of the Urengoy settlement on October 21. On board the helicopter were 22 people - 19 of them died, including three crew members.
The MI-8 was flying from the Suzunsky oil deposit (Krasnoyarskiy Kray) to Novy Urengoi (YANAO). Radio contact with the rotorcraft was lost soon after the takeoff. The helicopter did not arrived at its destination at due time.
Investigation into the accident is under way now.