Incident
The aircraft departed Mukachevo Airbase on a cargo flight to Moscow, carrying nine crew members and a load of air-air missiles destined for maintenance. Approximately 35 minutes into the flight, while cruising at night, the autopilot system failed and an alarm sounded. The crew identified the issue, reconnected the autopilot, and continued the flight.
One hour and 43 minutes into the flight, while cruising at an altitude of 7,500 meters, the autopilot system failed again. This time, no alarm sounded, and the crew was unable to identify the problem. Forty seconds later, the aircraft entered a dive and crashed in a swampy area near Semenivka. The aircraft disintegrated on impact, and all nine occupants were killed.
Probable Cause
The official investigation determined that the exact reason why the autopilot system disconnected by itself could not be established with certainty. Two assumptions were not ruled out: a crew member may have inadvertently disconnected the autopilot while touching the button with his body, or a possible failure of a switch connected to the autopilot system command circuit. However, the crew was considered partly responsible for failing to pay sufficient attention to the conduct of the flight and various instruments, which prevented them from identifying the problem and intervening in a timely manner to correct the situation.