What happened
On September 23, 2007, a Glaser DG 600 glider was prepared for flight at Oberpfaffenhlen airfield. Following the preparation, the pilot performed a control check. At 12:05 local time, the aircraft commenced a winch launch. Shortly after releasing from the tow rope, witnesses observed the glider performing unstable, pumping flight movements. Recognizing the danger, the pilot jettisoned the canopy and performed an emergency egress. The pilot landed safely and uninjured using a parachute.
The glider subsequently crashed near the winch station, approximately 350 meters northwest of the runway, striking a container garage. The impact caused heavy damage to the aircraft, specifically breaking the fuselage between the cockpit and the wing assembly and causing significant damage to the wings.
The investigation
The BFU examined the aircraft's condition and the mechanical state of the flight controls. The investigation confirmed that the aircraft's center of gravity and loading were within manual specifications and that all control surface connections were properly secured. The annual inspection had been completed in October 2006, and the aircraft had flown approximately 30 hours since that inspection.
Investigators focused on the elevator mechanism. During the disassembly of the horizontal stabilizer, the automatic control connection was found to be correctly positioned and connected. To investigate the pilot's report of "wax-soft" or extremely light control feel, investigators attempted to reconstruct a potential incorrect connection. They successfully managed to position the linkage in the guide track in a way that restricted elevator movement, mimicking the reported symptoms. However, this specific configuration would have been clearly detectable during the pilot's pre-flight control check.
Findings
- The aircraft's control surfaces were mechanically sound and properly connected.
- The pilot's pre-flight control check failed to identify the restricted elevator movement that occurred during flight.