What happened
On December 7, 2009, a Robin DR400-120, registration F-GABG, departed from the Fontenay-Trésigny aerodrome for a local flight. At the time of takeoff, weather conditions were suitable for VFR flight, with visibility reported at 8,000 meters at a nearby station. However, as the flight progressed, weather conditions deteriorated rapidly due to the sudden appearance of thick fog banks.
Around 10:35 am, the pilot communicated via radio that visibility was decreasing and that he was increasing his altitude. Following this exchange, the pilot ceased all radio communications with the aero club. At 12:11 pm, air traffic controllers from Seine Info established contact with the pilot, who reported that he was lost and flying at a low altitude within the fog layer. While controllers attempted to provide guidance to a suitable aerodrome, the aircraft's radar echo disappeared at 12:20 pm, and radio contact was lost.
The wreckage was subsequently located in a field. The investigation of the crash site and the aircraft revealed that the plane had struck the ground in a nearly vertical trajectory, indicating a loss of control. Engine examinations confirmed that the powerplant was delivering power at the time of impact.
The investigation
The BEA examined the flight path, weather reports, and the pilot's experience. While the local TEMSI weather forecast indicated a possibility of fog, the official METAR and TAF reports from Melun had not predicted fog for that period. Radar and radio analysis showed that for the 100 minutes preceding the accident, the pilot had performed numerous maneuvers within a 2-kilometer radius east of the departure aerodrome, an area that had already become unflyable due to the fog.
The pilot, aged 55, held a private pilot license and had accumulated 367 total flight hours. Notably, all flights conducted in the two years prior to the accident were local flights, typically lasting less than one hour.
Findings
- The accident was caused by a loss of control while flying at low altitude without external visual references.
- The pilot was caught by a rapid meteorological change involving thick fog.
- The flight path analysis indicated that the pilot did not attempt to climb above the fog layer or divert to another airfield until prompted by air traffic controllers.