What happened
On 2 August 2015, a Stewart S-51D Mustang (registration G-CGOI) was attempting a takeoff from a private grass runway in Benwick, Cambridgeshire. The weather was clear with light winds, and the runway surface was firm and dry. During the initial takeoff roll, the pilot noticed the aircraft drifting to the left. In an attempt to correct the track, the pilot reduced power to idle and applied braking.
Following this, a second takeoff attempt was made. As the aircraft accelerated and the tail lifted, it swung sharply to the left. Although the pilot managed to stop the yaw, the aircraft was tracking approximately 30 degrees off the runway centerline. The aircraft climbed at a steep angle before stalling and rolling to the left. The left wingtip struck the ground, causing the aircraft to rotate and come to rest with extensive damage. The engine detached from the firewall during the sequence and landed near the tailplane. The pilot, the sole occupant, suffered minor injuries.
The investigation
An investigation was conducted following reports from the pilot and a witness who was also an aircraft engineer. The witness, who had overseen the aircraft's reassembly and maintenance, observed that the pilot had previously reported difficulty turning the aircraft to the right during taxiing, though no mechanical cause was identified at that time.
Evidence from ground marks indicated that the aircraft's tracks curved toward the left edge of the runway. The tracks ceased approximately 75 meters before the first impact in the adjacent potato crops, suggesting the aircraft had either become airborne or generated enough lift to stop leaving tyre marks at that point. The investigation also noted that the aircraft, a 70% scale replica powered by a Chevrolet V8 engine, was significantly heavier than other aircraft using the airfield that day.