Date & Time:
Jul 3, 1971 at 1805 LT
Type of aircraft:
NAMC YS-11
Operator:
Registration:
JA8764
Flight Phase:
Landing (descent or approach)
Flight Type:
Scheduled Revenue Flight
Survivors:
No
Site:
Mountains
Schedule:
Sapporo - Hakodate
MSN:
2134
YOM:
1970
Flight number:
JD063
Country:
Japan
Region:
Asia
Crew on board:
4
Crew fatalities:
4
Pax on board:
64
Pax fatalities:
64
Other fatalities:
0
Total fatalities:
68
Circumstances:
While descending to Hakodate Airport, the crew encountered poor weather conditions. At an altitude of 6,000 feet, the airplane struck the slope of Mt Yokotsu located 18 km north of Hakodate Airport. The aircraft disintegrated on impact and all 68 occupants have been killed.
Probable cause:
The flight crew mistook a point approximately 5 nautical miles north of the Hakodate NDB as being just over the Hakodate NDB, a navigation aid, and initiated their descent from an estimated altitude of 6,000 feet in an attempt to cross the high station at 2,500 feet by making a single circle. The outbound flight leg was extended westward and because of a strong southwesterly wind, the aircraft drifted further to the north than the crew expected, striking the mountain. It is so considered that the accident was the consequence of a controlled flight into terrain.
