What happened
On May 18, 2023, a Burkard Grob Standard Cirrus glider was performing a local flight via winch launch at the "Auf der Schaufel" glider field near Bad Wildungen, Germany. Witnesses observed the aircraft take off from runway 01 with a steep climb rate, described as a "Kavalierstart."
At an altitude of approximately 70 meters, the winch cable snapped. Following the break, the glider transitioned into a horizontal flight attitude and entered a left-hand turn at low speed. In an attempt to fly a shortened circuit, the pilot executed a direction change of approximately 180 degrees. During this maneuver, the aircraft pitched over and entered a spin-like descent, impacting the ground. The pilot, a 59-year-old experienced aviator, sustained fatal injuries.
The investigation
The BFU investigation examined the aircraft, the winch operations, and flight data. Analysis of the FLARM (collision warning) data confirmed the aircraft reached a maximum altitude of 113 meters before the rate of climb decreased significantly at 109 meters, coinciding with the cable break. The data showed the aircraft entered a left turn with a radius of 49 meters roughly two seconds after the break, with the final signal recorded at 62 meters.
Investigators inspected the wreckage, noting that the nose of the fuselage was destroyed up to the wing level and the tailplane attachment had broken away from the fuselage. The investigation also reviewed the winch cable, finding the break occurred at the designated weak link. The blue-coded weak link had a breaking strength of 600 ± 60 daN, which exceeded the flight manual's requirement of a maximum 550 daN breaking strength.
Findings
- The cable break occurred at an altitude of approximately 70 meters.
- The weak link on the winch cable was rated for 600 ± 60 daN, which was higher than the maximum allowable 550 daN specified in the aircraft's documentation.
- The pilot attempted a shortened landing circuit following the loss of winch tension, which led to an uncontrolled flight attitude and subsequent impact.