Summary
On 9 August 2000, a glider accident occurred during a training flight at Rudolstadt. The aircraft, a Schleicher ASK 21, sustained severe damage. Both occupants, a flight instructor and a student pilot, suffered serious injuries.
Incident Details
The training flight began with a winch launch at 12:54. The instructor and student aimed to conduct a thermal flight but found no thermals, so the student initiated a landing approach. Perceiving the altitude as too high, the instructor took over control and performed a sideslip to reduce height. According to witnesses, the sideslip was initiated at approximately 40–50 meters and the recovery maneuver began at about 8–10 meters. During the rapid recovery, the glider's nose pitched up significantly above normal flight attitude. The glider then fell from about 5 meters, impacting the ground in a level attitude on its main landing gear. It rebounded and, after traveling about 100 meters, struck the ground again with the nose gear first.
Investigation
Investigation by the German Federal Bureau of Aircraft Accident Investigation (BFU) revealed that the weather conditions were normal and unremarkable. The glider had a valid Dutch airworthiness certificate. The instructor held a valid Dutch license and had sufficient experience and recent practice on gliders.
The instructor decided to correct the student's approach to avoid a long landing. After taking control, he initiated a sideslip at about 40–50 meters and ended it at very low altitude, causing the glider to enter a stalled state. The instructor noticed the speed decrease and attempted to lower the nose to regain airspeed, but due to the low altitude, the loss of control could not be corrected. The hard impact occurred with the glider in a level attitude; the subsequent bounce was largely uncontrolled, leading to another hard contact with a slight nose-down pitch.
Conclusion
The accident resulted from the instructor, during recovery from a sideslip, bringing the glider into a stalled condition at an altitude too low to safely recover.
Probable Cause
The accident was caused by the instructor, at too low altitude during recovery from a sideslip, causing the glider to enter a stalled condition that could not be safely terminated.