What happened
On 21 March 2010, a Pegasus Quantum 15-912, registration G-BZMI, was performing an air experience flight at Longacre Farm, Bedfordshire. During the fifth flight of the day, the pilot experienced a constant, uncommanded right turn immediately after rotation. Despite applying full opposite control, the pilot could not recover the aircraft to level flight. The aircraft lost altitude, the right wingtip struck the ground, and the aircraft came to rest in a field. Both the pilot and the passenger sustained serious lower limb injuries.
Earlier that day, the pilot had performed an aborted flight due to a similar right-hand turn. During a brief interval between flights, the pilot attempted to adjust the wing ribs in-situ to address the issue. Following the second takeoff, the aircraft's rightward banking became significantly more severe, leading to the loss of control.
The investigation
The AAIB examined the wreckage and the wing components of the aircraft. Investigators found that several wing battens had been reshaped significantly beyond the manufacturer's permitted limits. Specifically, some battens on the left wing showed an upward reflex of 50 mm, which is double the maximum allowed adjustment of 25 mm. Additionally, certain battens on the right wing had been adjusted with a downward bend.
Furthermore, the investigation noted that the pilot had attempted to manipulate the wing profile while the battens were still inside the sail, a method not endorsed by the manufacturer. The investigation also reviewed the flying school's procedures regarding passenger briefings and the maintenance of the wing'1s profile.