Flight and Weather Conditions
The aircraft was operating a flight from Zyryanka to Seymchan in support of the 121st geodetic expedition. The crew encountered below-minima weather conditions due to low clouds. Despite the conditions, the crew decided to continue the flight and did not return to the departure airport.
Deviation and Crash
The aircraft deviated from the prescribed flight path by 25 kilometers and descended while in clouds over mountainous terrain. It subsequently crashed into the steep slope of Mount Khapchagai, which has an elevation of 1,554 meters. The impact occurred at a height of approximately 1,200 meters. The crash site was located 61 kilometers northwest of Seymchan.
Casualties and Rescue
Of the two pilots, one was killed. Among the six passengers, four were killed. All survivors sustained serious injuries. The wreckage and the survivors were found a day later, on 23 September 1968.
Probable Cause
The official finding attributed the accident to the failure of the crew, who decided to continue the flight into below-minima weather conditions and failed to return to the departure point.