What happened
On Thursday, September 16, 1999, a Jodel D 119 amateur-built aircraft, registration F-PIYT, was conducting a local flight departing from the Saint-Rambert-d’Albon aerodrome. Approximately twenty minutes into the flight, while flying at an altitude of 1,500 feet, the pilot experienced an audible noise from the engine accompanied by heavy vibrations and a drop in engine speed to 1,800 RPM.
In an attempt to maintain power, the pilot applied full throttle and activated the carburetor heat, which temporarily raised the engine speed to 2,400 RPM. The pilot elected to climb over a wooded area to gain altitude. However, after several minutes, the engine ceased operation. Following an unsuccessful attempt to restart the engine, the pilot performed an emergency landing in a recently mown sunflower field. There were no injuries to the pilot and no damage to the aircraft.
The investigation
The investigation focused on the mechanical failure of the Télédyne Continental C-90-8-F engine. Upon removal and examination of the engine, investigators discovered severe damage to the crankshaft pinion, which had only four of its twenty-two teeth remaining. Additionally, the teeth on the camshaft and magneto pinions were found to be heavily worn and deformed.
At the time of the incident, the engine had reached 4,437 total operating hours. Records indicated that the engine had not been maintained by an approved workshop. The most recent significant maintenance, which included the replacement of the four cylinders, connecting rod bearings, and the crankshaft, had been performed in February 1998, when the engine had 4,234 hours.