What happened
On December 9, 2018, at Menuma Gliding Field in Saitama Prefecture, Japan, an Alexander Schleicher ASK 13 glider, registration JA215 and 52, was undergoing a winch-assisted launch for a solo training flight. The aircraft was operated by the Gakushuin School Corporation.
During the initial ground roll, the trainee pilot noted a slight leftward drift. Upon lifting off, the pilot applied forward pressure on the control stick to prevent an excessive nose-up attitude, following standard launch instructions. However, this maneuver proved excessive, causing the aircraft to fail to reach a normal climb attitude. At an altitude of approximately 5 meters and a speed of 100 km/h, the pilot observed the tow line parachute, which led her to believe the tow line had severed.
Following emergency procedures for a tow line separation, the pilot maintained a nose-down attitude. This resulted in a steep descent and a hard landing. The impact caused the aircraft to bounce and collide with the ground a second time before coming to a halt. The impact caused substantial damage to the airframe, including a collapsed nose, destroyed canopy, and cracked wings. The trainee pilot sustained serious injuries and was transported to a hospital.
The investigation
The Japan Transport Safety Board (JTSB) examined the flight history, the trainee's training records, and the aircraft's mechanical condition. The investigation focused on the pilot's maneuvers during the critical seconds after lift-off and the adequacy of the existing training syllabus provided by the Japan Student Aviation League (JSAL). Investigators also reviewed the cockpit environment, noting that the pilot did not recall receiving radio instructions from the flight instructor during the descent.
Findings
- The primary cause of the accident was the glider's failure to transition into a normal climb attitude and its subsequent excessive nose-down attitude during the aborted launch.
- This maneuver was driven by the pilot's excessive forward pressure on the control stick immediately after lift-off.
- The pilot's decision to abort the launch was prompted by the visual of the tow line parachute, an unusual sight that led her to misidentify the situation as a tow line break.
- A lack of practical training experience specifically simulating tow line failures at altitudes below 10 meters contributed to the pilot's inability to execute appropriate corrective maneuvers.
- The investigation noted that while the pilot had completed ground school and several dual flights, the training had not sufficiently prepared her for the specific dynamics of a low-altitude emergency.