What happened
On the evening of December 3, 2004, a Reims Aviation F 172 N, registered F-GIQA, was performing night training circuits at Enghien Aerodrome. The crew consisted of an instructor, a student pilot, and a passenger who was also a pilot.
During the pre-takeoff checks, the student pilot noted a momentary engine RPM fluctuation while testing the carburetor heat. The instructor visually inspected the engine and found no abnormalities. During the takeoff roll on the unpaved runway, the student pilot rotated at 50 knots. However, the aircraft's climb speed did not exceed 60 knots. As the instructor monitored the airspeed, the student pilot attempted to lower the nose to regain speed, at which point the student reported that visibility had vanished due to incoming fog.
The aircraft subsequently struck the ground approximately 1,500 meters past the end of the runway with a slight left bank and nose-down attitude. The impact caused the left landing gear to collapse, resulting in the aircraft flipping onto its back. The accident resulted in one serious injury to a passenger, while the instructor and student sustained two minor injuries.
The investigation
The investigation focused on the aircraft's performance during the initial climb and the environmental conditions at the time of the accident. Investigators examined the engine's power output, noting that the engine was delivering low power at the moment of impact. The aircraft's weight was approximately 1,015 kg, which was within the maximum takeoff weight of 1,043 kg.
Analysis of the runway conditions revealed an upward slope of 0.8%, which contributed to a longer takeoff roll than usual. Furthermore, the investigation looked into the meteorological data from nearby airports, such as Paris Charles de Gaulle, which indicated that low stratus and fog were moving into the area. The investigators also noted that the crew had relied on weather information from 15:00 UTC, which did not reflect the rapid deterioration of visibility occurring closer to the flight time.