What happened
On May 3, 2013, at approximately 14:52 UTC, a Grob Club Astir CS Jeans glider was participating in a winch launch on the grass runway 08 at Innsbruck Airport. Following the command to tension the cable, the winch operator accelerated the cable to full power. After a short ground roll, the aircraft lifted off but failed to transition into a steady climb. Instead, the glider maintained a nearly horizontal attitude for a brief period before abruptly entering an extremely steep climb.
As the aircraft reached an altitude of approximately 15 meters, it entered an overpowered flight state, causing the aircraft to stall and roll over the right wing. The glider struck the ground with its nose and right wing, resulting in one fatality and the total loss of the aircraft. The pilot sustained severe injuries during the impact.
The investigation
The Austrian Federal Safety Investigation Board (SUB) conducted an investigation into the accident, reconstructing the flight sequence through eyewitness accounts. The investigation examined the aircraft's maintenance records, the winch equipment, and the pilot's qualifications.
Technical analysis of the wreckage showed that the control surfaces, including the ailerons, elevators, and rudder, were properly connected and showed no evidence of pre-existing mechanical failure. The damage observed on the fuselage and wings was consistent with high-impact forces sustained during the crash. The investigation also confirmed that the aircraft's weight and center of gravity were within permissible limits and that all required documentation and airworthiness certificates were valid at the time of the accident. Additionally, the winch system was found to be functioning correctly.
Findings
- The primary cause of the accident was a steep climb angle during the winch launch, which led to an aerodynamic stall.
- The pilot had relatively limited flight experience, with approximately 44 total hours in gliders and only 1 hour and 22 minutes (9 launches) of experience specifically with the Grob Club Astir CS Jeans.
- Unfavorable wind conditions contributed to the accident, with winds recorded up to 20 knots and shifting by 180 degrees.
- The pilot's experience with winch-assisted takeoffs was also noted as limited.