What happened
On Friday, October 24, 2003, at 12:30 local time, a Robin DR 400-180, registration F-GLDR, departed from runway 06 at the Flers aerodrome. During the initial climb, before reaching an altitude of 300 feet, the pilot experienced a significant loss of engine power, with the engine RPM unable to exceed 1,700. Witnesses on the ground observed black smoke emanating from the aircraft.
In an attempt to return to the airfield, the pilot initiated a left-hand turn to approach runway 24. While maneuvering at a very low altitude, the aircraft banked to the right, causing the right wing and the engine cowling to strike the ground. The aircraft slid approximately 40 meters south of the runway 2/4 threshold, eventually coming to rest on its back. The impact resulted in the destruction of the aircraft and one passenger injury.
The investigation
The investigation focused on the engine's performance degradation and the mechanical state of the induction system. Upon inspection of the carburetor heating box, investigators discovered a 6-centimeter piece of rubber positioned near the jet. This rubber fragment originated from the bellows located between the air filter and the heating box, which serves to dampen vibrations and ensure a seal.
Further examination revealed that the air filter and the rubber bellows had been torn away and were found about 10 meters from the wreckage. The metal flange of the bellows showed a 15-centimeter section of missing rubber.
Records indicated that on June 29, 2003, a pilot had previously noted a similar power loss (maximum RPM of 2,000) in the aircraft's logbook. At that time, a club mechanic inspected the carburetor and removed a rubber fragment of similar size and origin. The mechanic reassembled the unit without the original fragment and notified the maintenance workshop, which subsequently ordered a replacement bellows from the manufacturer. The aircraft was cleared for flight on June 30, 2003, and had completed approximately 100 flight hours before the accident. At the time of the crash, the replacement part had not yet been received.