History of the Flight
On Saturday 26 October 2024, around 11:15 local time, a Robin DR400-160 (registration F-GREP) operated by Aéroclub de Pérouges Plaine de l’Ain “Robert et Henri DARMON” attempted a cross-country take-off from runway 16 at Pérouges-Meximieux aerodrome. The aircraft was occupied by a pilot and three passengers, including one seated in the front right seat who was also a pilot.
The pilot performed engine tests at the club parking area and then taxied to the holding point. After allowing a student pilot to complete a circuit and return, he lined up at the runway threshold and applied take-off power. At 105 km/h, he pulled on the stick, the aircraft adopted a nose-up attitude, and strong vibrations began. As the end of the runway approached, the pilot continued the take-off attempt. The aircraft veered left, departed the runway, crossed a fence, entered a harvested field, struck a large stone, and swerved right. The nose landing gear collapsed, and the aircraft came to rest at the edge of a maize field.
Examination of the Accident Site and Aircraft
Runway marks indicated that the main landing gear contacted the runway as the aircraft crossed the displaced threshold markings of runway 34 (120 m before the end of runway 16), and the aircraft began deviating left. A skid mark from the tail skid was observed. Between two sets of marks, evidence suggested the aircraft bounced with a high nose-up attitude. The aerodrome is surrounded by a wild boar fence with wires at 20 cm and 70 cm; the upper wire was torn off and found wound on the left main landing gear, while the lower wire remained intact. When it passed the fence, the aircraft was less than 1 m high. Run marks continued in the harvested field along the extended runway centerline.
Post-accident photographs revealed that the carburettor heat system was not activated, the throttle was at full power, the mixture was rich, and the elevator trim was set at index 6 (nose-up), outside the recommended take-off range. The flaps were found in the landing position, but according to statements, this position was changed by a passenger during evacuation. Examination of the engine revealed no anomalies that could have contributed, and the propeller damage indicated the engine was delivering power. Control linkages were continuous.
Pilot Information
The 60-year-old pilot held a Private Pilot Licence (PPL(A)) issued in 2012. He had logged approximately 370 flight hours, with 10 hours in the previous 12 months, all on F-GREP. He indicated that he was accustomed to flying with club members and passengers. The flight was planned as a cross-country to Brioude aerodrome, with the pilot flying outbound and the passenger in the right seat (also a pilot) flying the return. Before departure, he added 75 litres of fuel to the main tank (110 l capacity); there were about 20 litres in each wing tank. A weight and balance calculation, based on declared passenger weights and 150 litres of fuel, showed the aircraft was 40 kg below maximum weight (1,050 kg) and at the aft centre-of-gravity limit, within the envelope. He performed engine tests at the parking area and did not taxi immediately to allow a student pilot to clear the runway. Upon reaching the holding point, the engine was hot from the hold. He set flaps to the first detent (take-off) and the electric pump to ON before lining up.
During take-off power application, he noted no anomalies. Rotation was performed at 105 km/h, after which vibrations began. He checked the throttle was fully forward and continued. He believed the aircraft became airborne but could not gain height, experiencing several bounces. Seeing the runway end approaching, he did not reject the take-off; he tried to lift off to avoid a ditch that he thought existed (though it had been filled two weeks earlier, he did not recall this). There was no engine spluttering throughout the run. After the accident, he attempted to open the canopy, but it jammed after 30–40 cm. With a passenger's help, he forced it open sufficiently for evacuation.
Take-off Performance and Procedures
The grass runway (690 m, unpaved) was wet; 0.5 mm of rain had fallen during the previous night. For the DR400 at maximum take-off weight on a paved runway at the aerodrome's elevation (700 ft) and standard temperature, performance tables indicate a run distance of 320 m and a take-off distance of 630 m. For a dry grass runway, the distances increase by 15%; for a 10 kt headwind, they decrease by 15%. The flight manual does not specify additional distance for wet or greasy unpaved runways. The flying club requests pilots to use the entire runway length for take-off on limiting runways. The short-runway take-off procedure (brakes applied while increasing power) is optional.
Conclusions
After an apparently normal take-off run, the pilot initiated rotation. The aircraft had an aft centre of gravity and the elevator trim was set nose-up beyond the recommended take-off limit. The pilot's elevator input caused an unusual and excessive nose-up attitude, leading to tail skid contact with the ground. The extreme nose-up attitude prevented further acceleration; the aircraft remained on the backside of the power curve and bounced multiple times. The pilot, focused on the perceived presence of a ditch at the runway end (not recalling it had been filled), did not abort the take-off. He continued even after overrunning the runway and entering the ploughed field. Upon striking a stone, the aircraft veered, skidded, and its nose gear collapsed.
Contributing Factors
The investigation identified factors that may have contributed to the excessive attitude: an incomplete pre-take-off configuration check, resulting in take-off with the elevator trim beyond the nose-up limit. Additionally, an erroneous mental representation of obstacles at the runway end may have influenced the pilot's decision to continue the take-off.
Safety Lessons
An aircraft with an aft centre-of-gravity is more manoeuvrable but inherently unstable, requiring smaller elevator inputs during rotation to avoid an excessive attitude that prevents acceleration. On DR400s, rear-seat passengers and fuel in the centre tank significantly displace the centre-of-gravity aft. During flight preparation, careful passenger positioning and, if possible, preferential fuel distribution in the wing tanks (which have a lower arm) can mitigate this effect.