What happened
On April 30, 2014, at 11:50 local time, a Schleicher ASW20BL glider, registration F-CBDD, was performing a takeoff roll via aero-tow at the Fayence aerodrome. The aircraft was being towed by a Piper PA-25-235 Pawnee, registration F-GFPD.
During the initial stages of the takeoff roll, an assistant was running alongside the glider to maintain wing level. Shortly after the assistant released the left wingtip, the left wing dipped and made contact with the unpaved runway surface. This contact triggered a violent yawing motion to the left. As the glider rotated, the right wing lifted, causing the aircraft to tilt perpendicular to the flight path. The tension caused the tow cable to snap at the tow plane's attachment point. The glider subsequently overturned, struck the ground, bounced, and slid several meters before coming to a halt. The pilot sustained fatal injuries.
The investigation
The BEA examined the wreckage and recovered data from the tow plane's Flarm unit and a GoPro camera positioned near the runway threshold. The investigation confirmed that the flight controls were fully functional and the glider's flaps were set to the recommended takeoff position. The tow cable failure was determined to be a result of exceeding the cable's breaking strength due to the extreme forces of the rotation.
Investigators analyzed the sequence of events using frame-by-frame imagery, which showed the entire incident lasted approximately 10 seconds. The investigation also reviewed the pilot's experience, noting 980 total flight hours, though the pilot had no prior experience with winch launches. Meteorological data indicated a wind of 35 km/h with gusts up to 45 km/h.
Findings
- The primary cause was the pronounced friction of the left wingtip against the ground during the takeoff roll, which induced an unusually violent yawing and rolling rotation.
- The rapid onset of the rotation—occurring in just three seconds—left the pilot with insufficient time to execute recovery maneuvers.
- The specific recovery procedures taught for aero-tows (using control surfaces to level the wings) proved inadequate for this high-intensity rotation.
- High wind conditions likely contributed to the rapid destabilization, creating dynamics similar to those experienced during a winch launch.
- Because the pilot was performing an aero-tow rather than a winch launch, they likely did not have their hand on the release handle, preventing an immediate cable release.