What happened
On July 29, 2002, at approximately 13:10, a Schempp-Hirth Ventus CT motor glider was performing a winch launch for a thermal flight at the Lüsse airfield. The aircraft was being towed by a winch for a standard takeoff. During the initial climb phase, the aircraft entered a steep climb angle that was incompatible with the low towing speed. This resulted in the aircraft dropping below its stall speed, causing a wing drop to the left. The glider impacted the ground at a high pitch angle, approximately 316 meters from the runway threshold and 50 meters left of the centerline. The impact, which primarily involved the left wing and the cockpit area, resulted in the destruction of the aircraft and the fatal injuries of the pilot.
The investigation
The BFU investigation examined the aircraft, the airfield conditions, and the pilot's medical status. The Schempp-Hirth Ventus CT had a total operating time of 1,696 hours and had undergone its last annual inspection in March 2002. Investigators found no technical defects in the aircraft; all observed structural damage was consistent with the impact forces. The pilot, who had 748 total flight hours, was found to be in good health, with no evidence of medical impairment or alcohol influence at the time of the accident. The investigation also considered environmental factors, noting high ambient temperatures of 34°C, which may have caused ground shimmer, potentially affecting visibility between the winch operator and the glider.
Findings
- The primary cause of the accident was that the pilot maintained a climb attitude that was too steep for the low speed provided by the winch.
- This excessive pitch caused the aircraft to fall below its minimum flying speed, leading to an aerodynamic stall.
- The pilot was unable to recover from the stalled state because the aircraft was at too low an altitude (approximately 30 meters) to execute corrective maneuvers.