What happened
During a takeoff maneuver near the Lena River in the Yakutsk region, a single-engine aircraft experienced a sudden loss of stability. While the aircraft was ascending to an altitude between 50 and 60 meters, it entered a steep left bank of 65 degrees accompanied by a 25-degree nose-down pitch. The plane subsequently impacted the surface of the Lena River approximately 200 meters from the shoreline.
Following the impact, all four crew members managed to exit the cabin. However, the evacuation was not entirely successful; while three individuals reached the safety of the shore, the flight engineer succumbed to drowning during the incident.
Findings
Investigations into the accident determined that the aircraft suffered a loss of control due to locked ailerons. The investigation concluded that the crew did not sufficiently prepare the aircraft for flight, initiating the takeoff sequence while the aileron controls were in a locked state.