Accident
On 11 August 1998, a Bielsko-Biala glider was launched by winch for a thermal flight at Jena-Schöngleina. After reaching an altitude of 40 to 50 meters, the glider banked over its left wing and struck the ground in a nearly vertical, slightly inverted attitude. The pilot sustained fatal injuries, and the glider was destroyed.
Investigation
An investigator examined the scene. Witnesses stated that the flight was properly prepared and weather conditions were good. The runway in use was heading 200°, with wind from 230°–240° at 8 to 12 knots. The winch launch proceeded normally from initial acceleration to lift-off. After takeoff, the glider assumed an excessive climb angle, which the pilot did not correct. At 40 to 50 meters, an aerodynamic stall occurred, and the glider banked left. It subsequently rotated around its vertical and longitudinal axes, impacting the ground approximately 100 meters from the launch point.
Technical inspection of the glider found no control defects. All fractures in the structure and control rods were attributable to impact forces. The pilot held a valid license and had sufficient flying experience.
Review of the pilot's medical records revealed that flight fitness had been certified despite relevant exclusion criteria in his medical history. An autopsy at the Institute of Legal Medicine in Jena concluded that the injuries were accident-related and occurred during life. Acute health impairments that could have led to errors during the start could not be conclusively derived from organ changes but could not be ruled out.
Assessment
The investigation indicated that the glider was put into a climb with an excessively high angle of attack immediately after takeoff. When the stall speed for that condition was undershot, a stall developed, and the glider banked over. The available height was insufficient for a successful recovery. It could not be excluded that the pilot's reaction was impaired by a health condition.
Conclusion
The accident was caused by the glider stalling due to undershooting stall speed during the initial climb after winch launch, preventing recovery to normal flight attitude.