What happened
On May 27, 2009, a Schempp-Hirth Discus bT glider departed from the Klippeneck glider airfield via winch launch on runway 23. Shortly after releasing from the winch, the pilot extended the retractable engine to perform a functional test. However, the engine failed to start. Due to the low altitude, a return to the airfield was not possible.
The pilot flew in a southwesterly direction, attempting to restart the engine while experiencing a continuous loss of altitude. After approximately three minutes of flight, at an altitude of about 170 m AGL, the aircraft entered a left-hand turn. The engine remained extended during these subsequent restart attempts. In an effort to reach an available landing field, the pilot attempted an approach with an increased sink rate; however, the altitude was insufficient to clear obstacles.
The aircraft struck trees on a vegetated embankment, which caused the left wing to separate from the fuselage. The glider then overturned and came to rest on its left side on a field, supported by the extended engine and the tail unit. The impact resulted in one person being seriously injured and the total destruction of the aircraft.
The investigation
The BFU investigation utilized GPS data from a carried navigation device to reconstruct the flight path. Investigators examined the aircraft and found no technical defects; the engine was functional, fuel levels were sufficient, and the starter battery was in good condition. The aircraft's maintenance records showed the last annual inspection had been completed in March 2009.
Findings
- The pilot was appropriately licensed and possessed sufficient experience on the aircraft type.
- Weather conditions were favorable for VFR flight, with scattered clouds and moderate winds.
- The pilot failed to effectively coordinate the continuous engine restart attempts with the necessary preparations for an emergency landing.
- The pilot misjudged the sink rate of the glider while the engine was extended, leading to an approach that could not clear the terrain obstacles.