After passing a waypoint at Rostov the crew was instructed by air traffic control (ATC) to descend to an altitude of 5,700 m (18,700 ft).

As the Antonov plummeted towards the ground both right engines lost oil pressure, causing their propellers to go into fine pitch, inducing both of them to rotate at very high rpm.

The construction of the airliner was completed on 31 December 1958 and it had sustained a total of 14,337 flight hours and 9,081 takeoff and landing cycles at the time of the crash.

[1][2] Investigators discovered that a riveted seam of the right wing nine ribs wide had separated in flight due to excessive shear loads.

Static testing with partially and completely blocked outlets showed that the pressure build up was negligible, due mostly to the systems design having numerous other paths for the bleed air to escape.