What happened
On April 25, 2004, an LS 4 glider departed from the Kirchheim/TeckHahnweide glider airfield via aero-tow for a cross-country flight. Approximately one hour into the flight, near the town of Oberdigisheim, the pilot attempted an outlanding on a field. Witnesses observed the aircraft banking and then dropping from a low altitude. The glider entered a spin and struck the ground at a near-vertical angle. The pilot sustained fatal injuries, and the aircraft was destroyed.
The investigation
The BFU examined the wreckage and the flight conditions at the time of the accident. The investigation confirmed that the landing gear was extended and locked. While a flight data logger was on board, the impact was so severe that reconstruction of the flight path from the device was impossible. An autopsy of the pilot revealed no medical conditions or impairments that would have affected the ability to fly. The investigation also found no technical defects in the aircraft, which had undergone its annual inspection in March 2004.
Findings
- The aircraft was flying in the lee of a westward-sloping ridge, where wind conditions from 40° to 80° were expected to cause wind shear and increased sink rates.
- The pilot misjudged the effects of the lee-side turbulence during the approach to the landing site.
- The glider was flown at an insufficient airspeed during the final phase of flight.
- During a turn, the aircraft fell below its stall speed, triggering a stall and subsequent spin from an altitude too low to allow for recovery.