What happened
On September 9, 2015, a privately owned Hoffmann H-36 Dimona, registration JA2528, was conducting a familiarization flight at the Kitami District Temporary Operation Site in Hokkaido. During the landing phase, the aircraft touched down slightly left of the runway centerline. As the pilot attempted to correct the aircraft's direction using the right rudder pedal, the nose swung sharply to the right.
In an attempt to recover, the pilot applied maximum engine power following a suggestion from the passenger to perform a go-around. However, this sudden increase in power, combined with the existing directional instability, caused the aircraft to veer further off the runway. The aircraft exited the side of the runway and continued rolling until it struck the tops of trees located just beyond the site's boundary. The impact caused substantial damage to the aircraft, including a broken tail, damaged wing leading edges, and a broken propeller, though no injuries were reported.
The investigation
The Japan Transport Safety Board (JTSB) examined the flight history, the mechanical condition of the aircraft, and the pilot's recent experience. Investigators analyzed the inherent aerodynamic differences between tailwheel-type and nosewheel-type aircraft, specifically noting how the center of gravity being behind the main gear makes the JA2528 prone to ground loops. The investigation also reviewed the passenger's role, noting that the passenger had ceased active monitoring of the controls during the flight.