What happened
On 5 July 2017, a PIEL CP301A, registration G-ASLX, was being prepared for a flight from Mullinahone Airfield, Co. Tipperary, to Sligo Airport. The pilot moved the aircraft from its hangar to begin an engine start via the hand-swinging of the propeller. During this process, the pilot set the ignition to the 'ON' position and advanced the throttle to a setting higher than usual.
Because the aircraft was not occupied, the brakes were not engaged, and the wheels had not been chocked, the engine ignited and the aircraft immediately began to move forward. The aircraft traveled approximately 70 metres across the airfield before striking a ditch and a boundary hedge. The impact caused the aircraft to overturn, leaving it inverted on an electric fence in a neighboring field. Following the impact, fuel leaked from the aircraft and ignited, likely due to the electric fence, resulting in a post-impact fire that destroyed the aircraft. There were no injuries to the pilot, who was not on board at the time of the movement.
The investigation
The investigation established that the pilot was attempting to hand-start the engine alone. The pilot provided a detailed account and photographic evidence, noting that he was in a hurry to depart. The investigation also reviewed international safety guidance regarding the hazards of hand-swinging propellers, noting that such procedures should only be used when no other alternatives exist and should involve specific safety precautions, such as securing the aircraft and having an assistant at the controls.