What happened
On March 15, 2013, a privately owned Hoffmann H-36 Dimona, registered JA2405, departed Memanbetsu Airport for a recreational flight to Shikabe Airfield in Hokkaido, Japan. The aircraft was carrying a pilot and one passenger. During the flight, the aircraft went missing and was not located until March 18, 2013.
Search efforts led investigators to the northwest slope of a mountain peak measuring 1,903 meters in elevation, situated approximately 1.7 km north of Mt. Kamuiekuuch_uchikaushi. The impact destroyed the aircraft, though no fire occurred at the site. Both the pilot and the passenger sustained fatal injuries.
The investigation
The Japan Transport Safety Board (JTSB) examined flight tracking data from a portable GPS, communications between the pilot and Air Traffic Control, and meteorological records. Wind profiler data from the Japan Meteorological Agency indicated strong westerly winds, with speeds reaching 45 to 50 knots at altitudes between 1,650 and 2,600 meters.
Investigators also reviewed the flight path, which showed the aircraft descending and experiencing a rapid decrease in ground speed as it approached the Kyunosawa Valley. The investigation also noted that the aircraft's Emergency Locator Transmitter (ELT) was found switched off and without an antenna installed.