What happened
On 31 August 2004, a Pietenpol Aircamper, registration G-PIET, was conducting a training check flight at RAF Halton in Buckinghamshire. The weather conditions were favorable, characterized by a dry grass runway and a north-westerly wind of approximately 5 to 10 knots.
During the takeoff roll on runway 26, the aircraft encountered a bump while traveling at a speed below the required takeoff velocity. This impact caused the aircraft to bounce into the air. A sequence of two subsequent larger bounces followed. At the peak of the third bounce, the left wing dropped.
As the aircraft descended, it continued a leftward turn. The left undercarriage made contact with the ground and collapsed, leading the propeller to strike the surface. The aircraft then entered a ground loop to the left, which caused the right undercarriage leg to collapse. The tail skid subsequently dug into the ground, resulting in the breakage of the tail section. Both crew members, who were wearing full harnesses, sustained minor injuries and were able to exit the aircraft unassisted.
The investigation
The investigation examined the sequence of the takeoff roll and the physical impact of the aircraft with the runway surface. Investigators looked into the control inputs made by the crew during the bouncing sequence and the environmental factors present at the time of the accident. The instructor noted that a potential change in wind direction during the transition to flight might have contributed to a loss of airspeed and the subsequent wing drop.