What happened
The aircraft was operating a scheduled cargo route from Irkutsk to Bodaibo, with an intermediate stop at Kirensk. The payload consisted of apples and mail, totaling 2,222 kilos. Approximately one hour and thirteen minutes after departing Kirensk, the crew experienced a simultaneous loss of power in both engines. The captain initiated an emergency landing procedure, but the aircraft struck treetops before impacting the ground. It crashed into a wooded area located 25 kilometers from Parshino. The airframe was destroyed by the impact and subsequent post-crash fire, resulting in the deaths of all four crew members.
Findings
The investigation determined that the engine failure resulted from fuel system contamination. Water had entered the fuel supply, reaching levels of up to 16%, which caused partial icing within the tanks and supply lines. This prevented proper fuel delivery to the carburetors. The root cause was identified as procedural failures during the storage and handling of fuel at Kirensk. Fuel tanks were exposed to direct sunlight and lacked adequate waterproofing, allowing condensation to form. This moisture was not drained prior to refueling, leading to the contamination that caused the accident.