What happened
On 27 May 2015, a Robin R2160, registration G-OCFC, was performing a training flight at Bodmin Airfield, Cornwall. During the takeoff roll on the grass Runway 31, the aircraft initially accelerated normally, reaching approximately 50 kt by the midpoint of the runway. However, the aircraft then began to swerve toward the left.
Upon noticing the deviation, the instructor attempted to correct the heading, but the aircraft's airspeed failed to increase further. Despite efforts to rotate the aircraft for liftoff and the application of heavy braking, the aircraft could not stop before the end of the runway. The aircraft eventually came to a halt in a gorse bush. Both the pilot and the passenger were able to exit the aircraft by jettisoning the canopy, and there were no injuries reported. The incident resulted in damage to the wings, fuselage, and nosewheel assembly.
The investigation
The investigation examined the environmental conditions and the mechanical/operational actions during the takeoff roll. It was noted that the windsock was not visible from the start of Runway 31, making it difficult to assess wind conditions until the aircraft was halfway down the runway. The instructor observed that the wind direction had shifted 180 degrees, effectively creating a tailwind during the latter half of the takeoff attempt.
Furthermore, the investigation looked into the possibility of pilot input, specifically whether the student pilot had unintentionally applied the brakes, which may have contributed to the leftward swerve and the lack of acceleration. The aerodrome chart for Bodmin specifically warns of sudden changes in surface wind velocity due to sea breezes.
Findings
- A sudden change in wind direction to a tailwind significantly reduced the aircraft's takeoff performance.
- The inadvertent use of brakes by the student pilot may have caused the aircraft to swerve and prevented further acceleration.
- The windsock was not visible from the beginning of the runway, preventing the crew from identifying the wind shift before the takeoff roll began.