What happened
On August 11, 2017, an Alexander Schleicher ASW 19 B glider, registration LN-GCC, was participating in the Norway Cup competition. After approximately one hour of flight near a thermal, the pilot determined that insufficient altitude remained to return to the home aerodrome at Klanten. Consequently, the pilot opted to perform an outlanding at a pre-selected field located east of the Gol Campingsenter.
Upon approaching the field, the pilot evaluated the landing area from various angles. As the aircraft began its landing sequence, the left wing made contact with tall grass. This contact triggered a rapid ground loop, causing the aircraft to rotate nearly 180 degrees. The force of the maneuver resulted in structural failure of the tail boom and damage to the underside of the right wing.
The investigation
The Norwegian Safety Investigation Authority (NSIA) examined the aircraft and the circumstances of the landing. The investigation focused on the terrain conditions and the mechanics of the ground loop. Investigators noted that the landing field features slightly undulating terrain at one end, which may be difficult to discern from flight altitude. The inspection of the aircraft revealed that the lateral and downward twisting forces during the rotation caused the adhesive to fail at the upper fuselage joint and resulted in two distinct breaks in the tail structure. There was also minor damage to the right wing approximately 80 cm from the wing root.
Findings
- The primary cause of the structural damage was a ground loop initiated when the left wing struck tall vegetation.
- The uneven terrain at the landing site contributed to the difficulty in assessing the landing surface from the air.
- The pilot was uninjured during the event.