What happened
On November 16, 2004, a Robin DR 40 and-120, registration F-GNNY, was performing local circuit training at Chavenay Aerodrome. The pilot, flying solo after a planned companion was unable to join, intended to conduct a session of touch-and-go landings.
During the approach, the pilot became unsettled by encroaching cloud cover while on the downwind leg. Consequently, the pilot notified air traffic control of the intention to perform a full landing rather than a touch-and-go. The aircraft approached the final approach with an excessively high airspeed. Upon touchdown on the unpaved runway 28, the braking attempt proved ineffective. The pilot realized mid-runway that engine power had not been sufficiently reduced. Despite further braking attempts, the aircraft failed to decelerate adequately on the slippery grass surface, resulting in a longitudinal excursion. The aircraft exited the runway perimeter, coming to rest a few meters beyond the airfield fence.
The investigation
The investigation focused on the aircraft's performance capabilities relative to the runway conditions. At the time of the accident, the unpaved runway 28 measured 700 meters in length. The flight manual indicated a landing distance of approximately 450 meters on dry grass for a 700 kg aircraft, while the takeoff distance was approximately 600 meters under optimal conditions. The pilot admitted to being unaware of these specific performance values.
Furthermore, the investigation examined the pilot's operational habits. To manage the short runway lengths at Chavenay, the pilot had developed a habit of maintaining higher speeds and engine power during touch-and-go maneuvers than recommended for standard landings. The investigation also noted that the pilot had only performed one landing in the preceding three months.
Findings
- The pilot made the decision to use an unsuitable runway for performing touch-and-go maneuvers given the specific environmental conditions.
- The runway surface was notably slippery and wet, as indicated by the ATIS information prior to the flight.
- The pilot experienced significant stress due to the unusual nature of flying solo and the presence of low clouds.
- The aircraft sustained slight damage during the excursion.