What happened
On November 7, 2004, a Reims Aviation F 172 P departed from Dôle aerodrome for a VFR pleasure flight toward Bourg. The aircraft was carrying four occupants: the pilot and three passengers. During the flight, the aircraft encountered deteriorating weather conditions, including low cloud ceilings and reduced visibility.
As the aircraft approached the Massif du Revermont, it entered a layer of clouds. The pilot, attempting to maintain visual contact with the ground, likely descended to stay below the cloud base. However, the flight path led directly into the mountainous terrain. The aircraft struck trees on a steep slope at an altitude of approximately 1,410 feet. The impact resulted in two fatalities (the pilot and the front passenger) and two serious injuries to the rear passengers. The aircraft was destroyed in the crash.
The investigation
Investigators examined the wreckage located in a wooded area of the massif. The wreckage analysis showed that the aircraft's flight path was nearly horizontal at the time of impact and that the engine was producing power when the collision occurred. The investigation also reviewed the pilot's flight planning, which included a direct route but lacked specific waypoints or a designated safety altitude.
Meteorological data from nearby stations were analyzed, confirming the presence of low-level stratus clouds and intermittent visibility reductions. Radar tracking was used to reconstruct the flight path, revealing that the aircraft had drifted slightly east of its intended track and had not utilized the valley or highway as a navigational reference. The investigation also reviewed the pilot's experience and the weather briefings available on the morning of the accident.
Findings
- The primary cause of the accident was the loss of external visual references while in close proximity to terrain.
- The pilot failed to sufficiently monitor changing weather conditions and persisted in continuing the flight despite deteriorating visibility.
- Inadequate flight planning, specifically the lack of intermediate waypoints and failure to account for local terrain elevations, contributed to the accident.
- The pilot's decision to maintain a constant heading without correcting for navigation errors or seeking alternative routes (such as returning to Dôle or diverting to Lons-le-Saunier) led the aircraft into the mountains.