Some sources state that this was due to an accidental shutoff of fuel pumping to the aircraft's sump tank by the flight engineer, though the accuracy of this claim is uncertain.

[1] Due to the poor design of the Tu-154B, a single fuel pump failure could result in the stoppage of all three engines.

This resulted in an abrupt pitch and roll of the aircraft, the first sign of malfunction that the pilots noticed.

The pilots also attempted to use the aircraft's auxiliary power unit (APU) to restart the fuel pump, but its operation was disabled by design at altitudes above 3,000 metres (9,800 ft).

[3] The aircraft landed in a potato and barley field 5 kilometres (3.1 mi) southeast of Maksatikha at 1:32 p.m.