Incident Description
On a flight from Vinnitsa to Moscow-Bykovo, while cruising at an altitude of 5,700 meters, the crew disengaged the autopilot system. Immediately, the sliding cylinder of the MP-100 rudder trimming device deployed by 22.5 mm, causing the rudder to move to the right and reach the maximum deflection of 25° within one second. The aircraft lost control, entered a spin, and crashed at a speed of 350 km/h with a nose-down attitude of 50° in a field located 500 meters southeast of Viktorivka, 14.8 km southeast of Chernihiv Airport. The airplane disintegrated on impact, and all 52 occupants were killed.
Investigation Findings
The official investigation determined the probable cause to be a failure of the rudder trimming device during cruise flight. This failure may have been caused by either a technical issue in the electrical system or an unintended pressure applied to the trim control switch by one of the crew members while the autopilot system was still on.