What happened
A cargo operation departing from Ust-Kut Airport for Mirny ended in a fatal accident during an unplanned diversion. The aircraft was transporting 18 tons of cement when the crew received notification that landing at the intended destination, Mirny, was not possible due to technical issues. Consequently, the captain elected to divert to Lensk Airport, despite unfavorable weather conditions characterized by rain, snow, and cloud ceilings as low as 600 meters with visibility restricted to 2,500 meters.
While cruising at 8,000 meters, the flight was cleared to descend to 3,000 meters for the approach into Lensk. During the final phase of the flight, the pilot failed to maintain a safe altitude, causing the aircraft type to impact 20-meter-tall trees while maintaining a flat attitude. Following this initial impact, the plane continued its descent and crashed into a forested area approximately 420 meters beyond the trees. The wreckage was located 15.6 km before the runway threshold. The crash resulted in six fatalities and the total destruction of the aircraft.
Findings
Investigations concluded that the accident was caused by a premature descent leading to controlled flight into terrain. While the specific reason for the descent error remained undetermined, investigators did not rule out the possibility that an engine failure occurred during the approach. It was also noted that Lensk Airport lacked an Instrument Landing System (ILS) or any other ground-based navigation assistance at the time of the event.