Accident Details
While descending to Hakodate Airport, the crew encountered poor weather conditions. At an altitude of 6,000 feet, the airplane struck the slope of Mount Yokotsu, located 18 kilometers north of Hakodate Airport. The aircraft disintegrated on impact, and all 68 occupants were killed.
Investigation Findings
The official investigation determined that the flight crew mistook a point approximately 5 nautical miles north of the Hakodate Non-Directional Beacon (NDB) as being directly over the navigation aid. Believing they were above the NDB, the crew initiated a descent from an estimated altitude of 6,000 feet, intending to cross the high station at 2,500 feet by executing a single circle. However, the outbound flight leg was extended westward. Due to a strong southwesterly wind, the aircraft drifted further north than the crew expected, leading to the collision with the mountain.
Probable Cause
The accident was determined to be a controlled flight into terrain, resulting from the crew's misidentification of their position relative to the Hakodate NDB and the subsequent descent under the influence of strong winds, causing the aircraft to drift off course and strike Mount Yokotsu.