What happened
On 4 August 2007, a Denney Kitfox Mk 3, registration G-BWYI, was attempting takeoff from a private grass airstrip located at Rollington Farm, near Corfe, Dorset. The strip was approximately 400 metres long and 18 metres wide, oriented southwest, and bordered by long grass on both sides.
As the pilot applied power for the takeoff roll, the aircraft began to drift toward the left. The pilot attempted to correct this movement by applying right rudder, but the control input proved insufficient to maintain the centerline. The left wheel subsequently entered the long grass adjacent to the runway. This contact increased friction and caused the aircraft to swing further left, eventually tipping forward and coming to rest in an inverted position. Both occupants exited the aircraft without assistance and sustained no injuries.
The investigation
The investigation examined the aircraft's engine and the pilot's experience. The aircraft was powered by a Rotax 912 piston engine. The pilot, who had 274 total flying hours, noted that this specific engine was more powerful than the ones he had previously operated. The investigation also noted that the pilot had not directly notified the AAIB of the occurrence, a fact that only became known when the Light Aircraft Association received a permit application for the repaired aircraft.
Findings
- The high power setting of the Rotax 912 engine produced a significant clockwise propeller rotation, which created a yawing moment to the left.
- The pilot was unable to counteract this leftward yaw with sufficient right rudder.
- The narrow width of the airstrip provided very little margin for error or time for corrective maneuvers.
- Contact with the long grass on the side of the strip increased the leftward swing, leading to the aircraft tipping onto its back.