What happened
On May 7, 2016, a Robin DR400-180, registration F-GLDM, was conducting a local flight from Saint-Cyr-l’École. During the pre-flight taxi, the pilot noticed the oil pressure indicator moving into the yellow arc. After consulting an instructor, who suggested that relative wind during takeoff might return the pressure to the green arc, the pilot proceeded with the flight.
While navigating approximately 16 NM from the departure airfield, near Montfort-l’Amaury, the pilot performed a turning point checklist. Shortly after, the oil pressure indicator returned to the yellow arc, and several red warning lights illuminated. At this moment, the engine suddenly lost power. The pilot prepared for a forced landing in a field near the Buisson-Défleuri ultralight airfield.
During the landing roll, the aircraft traveled approximately 170 meters before the nose gear collapsed while crossing a dirt track. The aircraft sustained heavy damage. The pilot and passenger successfully evacuated the aircraft after the pilot disconnected the battery and alternator.
The investigation
The investigation focused on the cause of the engine failure and the pilot's actions during the emergency. Investigators examined the fuel selector valve and the cockpit environment. It was noted that bright sunlight on the dashboard prevented the pilot from noticing the red warning lights immediately.
Post-accident inspections of the fuel selector revealed a chip in the paint on the control knob, which may have caused visual confusion. The chief pilot of the aero club observed that the fuel selector was in the "closed" position following the accident. Furthermore, an inspection of the engine fuel drain showed no fuel present, consistent with a fuel starvation scenario.
Findings
- The engine failure was likely caused by the unintentional cutoff of the fuel supply by the pilot.
- The pilot's intense focus on the fluctuating oil pressure likely prevented him from identifying the fuel starvation as the primary cause of the power loss.
- The ergonomics of the fuel selector, compounded by a chip in the paint on the selector knob, may have contributed to the incorrect valve setting.
- High levels of sunlight on the instrument panel hindered the timely detection of the red warning lights.