What happened
On 23 September 2006, a Schleicher ASW 20L glider, registration BGA 4354, was undergoing a winch launch at Keevil Airfield in Wiltshire. The flight was part of a private session involving members of a local gliding club. Following an initial aborted launch attempt due to a cable overrun, a second launch was attempted from a new position on the runway.
As the aircraft became airborne, the right wingtip made contact with the soft ground. This contact triggered a rapid yaw and an uncontrollable roll to the right. The winch cable remained attached to the aircraft throughout the sequence, preventing the pilot from terminating the tow. The glider continued to roll until it came to rest in an inverted position. The pilot sustained 1 fatal injury, dying from severe head trauma four days later after the cockpit canopy disintegrated upon impact.
The investigation
The AAIB examined the wreckage and the aircraft's flight controls. Investigators found that the right wing had suffered an overload failure, and the tail section had detached, which allowed the canopy to strike the ground. The investigation also looked into the ergonomics of the cable release control, noting that the position of the knob could make it difficult for a pilot to operate it quickly if their hand was not already placed on it during the initial launch phase.
Findings
- The right wingtip contact with the ground initiated a roll that could not be recovered using aerodynamic controls.
- The winch cable release was not activated during the onset of the roll.
- The aircraft's tail structure failed during the impact, leaving the pilot's head unprotected.
- The left lap strap attachment failed because the design load was exceeded during the accident sequence.