What happened
On June 1, 2005, a Diamond DA 40 (registration F-GUVH) was performing a flight from Montpellier to Brive for a short-duration flight involving a landing and takeoff. During the initial climb following departure, the pilot experienced several brief periods of decreased engine power. After a few minutes of stable flight, the pilot attempted to continue the navigation toward Montpellier.
While climbing to flight level 55, the engine power decreased once again. The pilot decided to return to the Brive aerodrome. While flying on a tailwind component, the power loss became increasingly severe, prompting the pilot to perform an emergency landing at the airfield. There were no injuries and no damage to the aircraft.
The investigation
The investigation focused on the engine and its associated components to determine the cause of the power fluctuations. Technical examination of the engine and its accessories revealed premature wear on the vibration damper that connects the engine to the propeller reduction gear. This wear prevented the engine's power from being transmitted effectively to the propeller.
Investigators also reviewed the maintenance history of the aircraft. At the time of the incident, the engine had completed 200 hours of operation since its last service. The maintenance program in place required the vibration damper to be overhauled every 600 hours. The specific component installed on the aircraft was a previously overhauled part.