What happened
On August 27, 2017, a Hoffmann H-36 Dimona, registered JA2406, operated by the Fukushima Motor Glider Club, crashed in the vicinity of the Bandai-Azuma Skyline Fudosawa Bridge in Fukushima Prefecture. The flight departed from Fukushima Sky Park for a leisure flight, originally intended to remain within a nine-kilometer radius of the airfield.
During the flight, the aircraft entered a narrow and deep valley. While navigating the terrain, the pilot encountered a mountain slope and attempted a sharp left turn to avoid a collision. This maneuver caused the aircraft to lose airspeed, leading to a stall and a subsequent left spin. The aircraft struck the valley slope, resulting in one fatality and one serious injury. The aircraft was destroyed upon impact.
The investigation
Investigators examined the flight path using handheld GPS records and analyzed the meteorological conditions at the time of the accident. The investigation focused on the aircraft's altitude relative to the surrounding ridges, the aerodynamic limits of the Hoffmann H-36 Dimona, and the pilot's maneuvers within the valley.
Technical analysis of the wreckage revealed that the engine was running at cruise power at the time of impact, but the control system had been ruptured. The investigation also noted that the flight plan had not been updated with the Ministry of Land, Infrastructure, Transport and Tourism after the pilot deviated from the original intended route, which complicated the initial search and rescue efforts due to the lack of a known location.