What happened
On Saturday, April 25, at 15:45, a Nicollier HN 700 aircraft, registered F-PLSD, was involved in an incident at Bergerac (AD Bergerac) during a private flight. While attempting to address a starting issue, the pilot exited the cockpit to manually swing the propeller to induce compression in the engine. During this process, a passenger remained inside the aircraft with the battery contact switch in the 'on' position. Upon the first rotation of the propeller, the engine ignited unexpectedly. In an attempt to secure the aircraft, the passenger applied the handbrake with significant force, but the aircraft moved forward, resulting in a collision with a pylon.
The investigation
The investigation focused on the sequence of events leading to the engine ignition and the subsequent movement of the aircraft. Investigators established that the engine started during the manual propeller swinging process while the electrical system remained active. The investigation also examined the mechanical impact of the movement, which caused structural damage to the aircraft.
Findings
- The primary cause of the engine ignition was the propeller being swung while the battery contact was still engaged.
- The aircraft sustained damage to the engine cowling and the propeller.
- The movement of the aircraft was exacerbated by the sudden engine start despite the passenger's attempt to use the handbrake.