What happened
On May 17, 2012, a Rolladen Schneider LS1-c glider was being towed from the Lauf-Lillinghof airfield by a TL Ultralight Dobrovskeho CR / TL 96 Sting. The tow was being conducted using a 40-meter nylon rope attached to the glider's center of gravity coupling. During the initial climb, the glider pilot successfully overtook the ultralight aircraft at an altitude of approximately 50 meters.
After the glider passed the tow plane, the pilot attempted to use airbrakes to reposition the aircraft behind the tug. Once back in position, the pilot released the tow rope. Following the release, the pilot decided to perform an outlanding, which required flying over a small wooded area. During this maneuver, the glider entered a strong sink rate, leading to a collision with tree tops and a subsequent impact with the ground. The pilot was able to exit the aircraft independently.
The investigation
The BFU examined the flight sequences of both aircraft and analyzed data from an LX 20 data logger installed in the glider. The investigation established that the tow plane experienced a sudden pitch-up of the tail and a loss of airspeed following the moment the glider overtook it. The pilot of the ultralight reported that he was unable to correct this pitch change with the elevator and subsequently chose to release the tow rope.
Physical inspection of the Rolladen Schneider LS1-c revealed significant structural damage. The aircraft's wings were heavily damaged, with the right wing breaking approximately one meter from the fuselage. The landing gear had penetrated the ground by 10 cm. The investigation found no mechanical or control failures in the glider prior to the impact.
Findings
- The glider pilot sustained serious injuries.
- The glider sustained heavy damage.
- The primary cause of the accident was the glider entering a strong sink rate while attempting to navigate through a wooded area during an outlanding maneuver.