What happened
On June 26, 2012, an instructor and a student pilot were conducting a training flight consisting of local circuits at the Chavenay Villepreux aerodrome. During the first touch-and-go maneuver on runway 28, the Robin DR400-120, registration F-GGHX, struck the top of a perimeter fence located at the end of the runway. Following the impact, the instructor performed a low pass on runway 10 to allow the air traffic controller to assess the damage before landing on runway 23. The aircraft sustained heavy damage, including broken ribs and torn fabric on the underside of the right wing, as well as damaged wheel fairings.
During the maneuver, the instructor noted that the student pilot applied power late and experienced some hesitation in the sequence of actions. The aircraft's wheels touched down at an offset threshold, and the instructor performed the rotation once rotation speed was reached. The instructor also noted that while they typically use the longer runway 23 for such maneuvers, runway 28 was in service at the time, with calm winds and slippery, grass runway conditions.
The investigation
The investigation examined the runway geometry and the physical characteristics of the obstacle. It was determined that the fence, which stands 1.20 meters high, was positioned only 8.40 meters from the end of the runway. Calculations based on the aircraft's flight manual indicated that a standard takeoff from the offset threshold on runway 28 would likely result in the aircraft passing 15 meters above the ground approximately 10 meters beyond the runway end, placing it directly in the path of the fence.
An audit of the aerodrome conducted by the DSAC/N prior to the accident revealed that the fence was non-frangible and protruded into the takeoff clearance zones for all runway headings. The investigation also noted that the club had equipped the aircraft with a fixed-pitch propeller to improve performance on short runways, specifically for use on runways 10 and 28.
Findings
- The primary cause of the accident was the presence of a non-frangible fence within the takeoff clearance zone.
- The crew failed to verify if the available runway length was compatible with the aircraft's performance requirements before attempting the touch-and-go.
- The student pilot's hesitation during the maneuver contributed to the event.
- Frequent use of the runway for touch-and-go maneuvers without prior performance calculations contributed to the accident.