Incident Overview
On a flight for a geological expedition, a single-engine airplane departed Irkutsk Airport at 1530 local time bound for Nizhneangarsk, Buryatia, with an intermediate stop in Kachug. The aircraft carried two pilots, one passenger, and 800 kilograms of various goods. After a fuel stop, the crew departed Kachug Airport at 1710 local time in marginal weather conditions.
Last Communications
At 1727 local time, the crew requested and received clearance to descend from 2,700 meters to 2,300 meters for reasons not specified. Twelve minutes later, while cruising at 2,300 meters, the crew informed air traffic control of their position in the region of Touloun Lake and estimated their arrival at the next waypoint, Cape Sheremshan, at 1815 local time.
Disappearance and Search
After the crew failed to make further contact and the aircraft did not arrive in Nizhneangarsk, search and rescue operations were initiated. These efforts were abandoned 17 days later when no trace of the aircraft or its three occupants was found. It is believed that the airplane crashed in a mountainous region northwest of Lake Baikal, near the border between Irkutsk Oblast and the Republic of Buryatia.
Probable Cause
Due to lack of evidence, as the wreckage was not found, the exact cause of the accident could not be determined. However, the following three hypotheses were not ruled out: loss of control due to severe icing, engine failure, and controlled flight into terrain while cruising in clouds.