What happened
On May 2, 2008, a privately owned Grob G109B motor glider, registration JA2569, was conducting a pleasure flight at the Hida Temporary Operation Site in Gifu Prefecture. The flight, which included the captain in the right seat and a passenger in the left seat, involved a routine flight within a nine-kilometer radius of the airfield.
During the landing approach to Runway 10, the aircraft experienced a series of bounces on the runway. Following a second touchdown, the pilot attempted a go-around to avoid a dangerous situation involving another glider parked on the runway overrun. During this maneuver, the aircraft's altitude and airspeed were not properly maintained. The aircraft deviated from the runway, struck a wire netting fence, and eventually crashed into trees in a wooded area located approximately 140 meters east of the runway end. The impact caused the engine to stop and the propeller blades to tear, resulting in the complete destruction of the aircraft. Both occupants sustained minor injuries.
The investigation
The investigation examined the flight history, the mechanical state of the aircraft, and the pilot's control inputs. Investigators analyzed the position of the airbrake control lever, which was found in an unlocked, partially open position, and noted that twigs had become lodged between the airbrake and the wing surface. The investigation also reviewed the pilot's experience, noting that while the captain was a qualified pilot, he had very limited experience performing landings from the right-hand seat at this specific, shorter airfield. Meteorological data confirmed calm wind conditions at the time of the accident.
Findings
- The aircraft entered a porpoising state because the pilot failed to flare sufficiently during the landing.
- The pilot's ability to manage the landing was compromised by the difficulty of operating the airbrake lever with the right hand while seated in the right pilot seat.
- The go-around maneuver was unsuccessful because the pilot failed to maintain sufficient power and airspeed, and the airbrake remained in an open position, hindering climb performance.
- The pilot attempted a go-around after repeated bounces rather than initiating the maneuver immediately after the first bounce.
- The pilot's decision to fly from the right seat, despite having limited experience with right-seat landings at this specific site, contributed to the loss of control over the airbrake and throttle during the critical phases of landing and go-around.