What happened
On Sunday, February 15, 1998, at 11:30, a Robin DR 400 (registration F-GBVJ) was conducting a local flight near Saint-Jean-d'Angély. While cruising at 1,500 feet, the aircraft's Lycoming O-235 H2C engine experienced a sudden drop in power accompanied by intense vibrations.
The pilot monitored the engine's oil pressure and temperature, finding both to be within normal limits. In an attempt to mitigate the vibrations, the pilot reduced power to find a more stable engine speed; however, the engine subsequently began to overheat. The pilot decided to divert to the nearby Saintes aerodrome, where a normal landing was completed without further incident.
The investigation
Following the event, a ground inspection of the engine was performed. Investigators identified a lack of compression in one cylinder. Furthermore, the inspection revealed the presence of oil on the spark plugs and metallic particles within the oil filter. The engine had recorded 1,748.51 flight hours since its last overhaul and was sent to the manufacturer for further technical expertise.