What happened
On July 17, 2011, a Diamond DA 40, registration F-GNJU, departed Dinard aerodrome for Pontoise with one passenger on board. During the flight, the pilot contacted Rennes flight information services, stating an intention to maintain a low altitude. Radar tracking showed the aircraft cruising between 1,000 and 1,500 feet for most of the journey. However, in the final 30 seconds of the flight, the aircraft began a descent as it approached the terrain near Mortain. Radar contact was lost at 12:58 local time.
The wreckage was located approximately 300 meters from a television antenna. The top of the antenna structure sat at an altitude of 1,368 feet, placing its guy wires at a height of 328 feet above the ground. The impact resulted in two fatalities and the total destruction of the aircraft.
The investigation
The investigation focused on the flight path, engine performance, and meteorological conditions. Radar data confirmed the aircraft's descent toward the terrain shortly before the accident. Examination of the wreckage revealed that all structural damage was a result of the ground impact. Investigators found electrical wiring from the aircraft's right wing suspended on an antenna guy wire, with debris from the right wing scattered between the antenna and the crash site. An analysis of the FADEC confirmed that the engine was functioning normally prior to the collision.
Meteorological analysis showed that the area near Mortain was experiencing stratocumulus clouds with bases potentially lower than 1,300 feet. While the pilot had reviewed weather forecasts (METARs and TAFs) for several aerodromes prior to departure, those forecasts indicated risks of thunderstorms and reduced visibility.
Findings
- The pilot's decision to proceed with the flight was likely driven by a desire to reach the intended destination despite unfavorable weather.
- The accident was caused by the decision to conduct a VFR flight at low altitude under weather conditions unsuitable for visual flight.