What happened
On June 24, 2007, a Schempp-Hirth Discus BT motor glider departed from Unterwössen via aero-tow for a cross-country flight. After more than four hours of soaring in the Austrian Alps, the pilot attempted to continue the flight using the retractable engine approximately 10 km south of Kössen. However, the engine failed to start.
Unable to maintain powered flight, the pilot attempted to return to the airfield in a gliding configuration. While flying over Kössen at an altitude of approximately 600 m AGL, the pilot declared a direct approach to runway 06 at Unterwössen. Due to insufficient altitude to complete the approach to the runway, the pilot was forced to perform an emergency landing in a grassy field located approximately 910 m southwest of the airfield. During the impact, the aircraft struck the ground at a longitudinal pitch of approximately 30 degrees. The pilot sustained serious injuries, and the aircraft was heavily damaged.
The investigation
The BFU examined the wreckage and recovered flight data from onboard satellite-based recording devices to reconstruct the flight path. The investigation focused on the aircraft's condition and the circumstances of the engine failure. Physical examination of the aircraft revealed that the landing gear had been extended but was not locked. The investigation found no evidence of any technical malfunction or mechanical failure within the aircraft itself.