What happened
On December 28, 2008, at approximately 15:12 JST, a privately owned Alexander Schleicher ASK23B glider, registration JA2382, crashed while attempting to land at the Itakura Gliding Field in Tochigi Prefecture. The aircraft was being operated for a leisure flight and had been towed to an altitude of 3,000 feet before being released for approach.
During the final approach to runway 3 and 33, the aircraft's right wing struck a tree located beneath the flight path. The impact caused the glider to crash to the ground, resulting in the total destruction of the aircraft and the death of the pilot. Witnesses at the airfield observed that the aircraft was flying at a lower altitude than required for the prevailing wind conditions and noted that the air brakes were deployed twice during the final stages of the approach.
The investigation
An investigation by the JTSB, with participation from German authorities, examined the flight history, meteorological conditions, and the aircraft's mechanical state. Investigators analyzed witness statements from club members and instructors, as well as the pilot's recent training records.
Key areas of focus included the wind conditions at the time of the accident, which were reported as strong, with gusts reaching up to 13.6 m/s in nearby stations. The investigation also reviewed the pilot's recent flight experience, noting that while the pilot had completed an annual flight review one week prior, he had not flown a glider in approximately three months and was operating a single-seat model for the first time.
Findings
- The aircraft was flying at an altitude that was too low for the prevailing strong wind conditions during the downwind leg.
- The pilot deployed the air brakes while at a low approach altitude, which caused the glider to sink significantly.
- The pilot's recent training in multi-engine airplanes may have affected his ability to transition back to the specific maneuvering requirements and steeper approach angles of a glider.
- The aircraft was flying at a higher airspeed than appropriate for calm conditions, likely due to the wind, which contributed to the difficulty in maintaining the correct glide path.
- The tree involved in the collision was located under the final approach path but was not an obstruction to a standard landing under normal conditions.