What happened
On April 11, 2013, a Diamond HK 36 TTS departed from the Aßlarer Hütte glider airfield at approximately 15:00 local time for a local flight. The aircraft was the only one operating from the airfield at the time, and no flight controller was present.
At approximately 15:45, while returning to the airfield, the pilot was flying along runway 27. At an altitude of about 40 meters, the aircraft encountered turbulence. The pilot reported that the turbulence caused the aircraft to shift to the left, leading to a loss of control where the left wing dipped. In an attempt to correct the situation, the pilot increased power, but the aircraft pitched up and continued to drift left. The left wingtip struck a paved area near the control tower, and the aircraft subsequently rolled onto its left wing. The right wing struck the roof of a hangar, and the fuselage impacted the ground near the building's wall. The impact was severe enough to break the tail boom, leaving the fuselage standing vertically against the hangar wall.
The investigation
The BFU examined the wreckage and the flight circumstances. The investigation confirmed that the aircraft's control surfaces were fully functional and no mechanical failures were identified. The aircraft, a 1998 model, had a total time of approximately 3,780 hours. The pilot, who held a valid medical certificate and extensive flight experience of over 5,000 hours, was able to exit the wreckage on his own, though he sustained serious injuries.
Findings
- The aircraft encountered turbulence at a low altitude of approximately 40 meters.
- The pilot's attempt to apply power caused the aircraft to pitch up and continue the leftward drift.
- The impact with the hangar roof and the ground caused significant structural damage, including the separation of the right wing and the breakage of the tail boom.