What happened
On June 21, 2008, at approximately 10:00 local time, a privately operated Jodel D 119 (registration F-PMED) was being prepared for a local flight at Annecy airport. The pilot had moved the aircraft from its hangar and secured the main landing gear with chocks.
As part of the pre-start routine, the pilot performed a procedure involving injecting fuel into the engine cylinders five to six times using the throttle. Following this, the pilot exited the cockpit to manually swing the propeller to lubricate the engine's mechanical components. During this process, the engine unexpectedly ignited. The rotating propeller struck the pilot's arm and knee. The pilot managed to climb back into the cockpit to switch off the magneto contacts, after which a bystander provided assistance.
The investigation
The investigation focused on the sequence of events leading to the engine ignition and the pilot's pre-flight actions. Investigators examined the aircraft's engine, a Continental C 90-12 F equipped with an electric starter, and the wooden Léger A 726 propeller.
It was established that the pilot's practice of priming the engine with fuel was not a requirement for this specific model equipped with an electric starter. While the aircraft's 196lar flight manual included procedures for manual propeller swinging to lubricate parts, the investigators noted that such practices were largely obsolete due to the use of modern synthetic oils, which maintain better fluidity than the mineral oils used in 1964. Furthermore, the pilot could not recall setting the magneto switches to the 'on' position during the cockpit preparation.
Findings
- The engine started unexpectedly during manual propeller rotation.
- The pilot sustained one injury caused by contact with the propeller.
- The primary cause was the application of an inappropriate procedure for this specific aircraft model, specifically the practice of priming the engine with fuel before manual swinging.
- Inattention during the pre-start preparation contributed to the event.