Incident
The crew was scheduled to fly from Irkutsk to Novosibirsk but en route weather at the destination deteriorated, prompting a diversion to Krasnoyarsk Airport. Approaching the Krasnoyarsk area at night, air traffic control cleared the crew to descend to 1,500 meters. While descending to an altitude of 1,725 meters in poor visibility, the twin-engine aircraft collided with the east slope of Mount Sivukha, which rises to 1,807 meters. The mountain is located 30 km from the Mana River.
Search and Recovery
When the aircraft failed to arrive in Krasnoyarsk, search and rescue operations were launched but were suspended a few days later when no trace of the aircraft or its 19 occupants was found. The wreckage was eventually discovered in June 1955, approximately 132 km south of the intended flight route. The aircraft was destroyed on impact. All 19 occupants were killed, including nine foreign citizens: one Polish, one Chinese, four from Cyprus, and four United Nations Organization emissaries in Vietnam.
Investigation
The official investigation determined that at the time of the accident, the aircraft was off course by 132 km and had deviated from the prescribed flight path by 10 degrees due to strong winds blowing from the northwest at up to 130 km/h. The crew had been cleared to descend to 1,500 meters, but the minimum safe altitude in the area was 2,100 meters. Incomplete information regarding wind components, which did not reflect actual conditions, was provided to the crew.
Probable Cause
The probable cause as stated in the official findings: The aircraft was off course by 132 km and deviated from the prescribed flight path by 10 degrees due to strong winds from the northwest up to 130 km/h. Contributing factors included poor flight organization and monitoring, allowing the crew to descend to 1,500 meters despite a minimum safe altitude of 2,100 meters in the area, and incomplete wind information transmitted to the crew that did not reflect true conditions.