What happened
On June 9, 2006, at approximately 12:30 PM, a Bell 47 G2 helicopter, registration F-GFHN, was performing agricultural spraying operations in Ampuis, France. The pilot had been working in the area since 8:00 AM and was conducting the final spraying pass of the morning session.
While flying at an altitude of approximately five meters and a speed of 40 km/h, the pilot attempted a 180-degree turn. During this maneuver, the aircraft struck medium-voltage power lines. The impact caused the pilot to experience difficulty controlling the cyclic stick. While attempting to maintain flight, the right skid of the helicopter struck the top of a pine tree. The pilot subsequently managed to land the aircraft on a small path within a vineyard located below the initial flight path.
The investigation
The investigation focused on the circumstances surrounding the collision and the visibility conditions at the time of the accident. Investigators noted that the pilot was wearing sunglasses and the sun was positioned behind the aircraft. The cockpit canopy was partially obscured by a layer of dust and chemical spray residue.
While the pilot had performed aerial reconnaissance of the plots the previous evening and the morning of the accident, the specific power lines were not identified. The pilot noted that a similar power line was visible approximately 100 meters to the north, which eventually connected to the line that was struck. The investigation also examined the damage to the aircraft, which included severed electrical cables, a damaged rotor mast, and bent control linkages.
Findings
- The collision was caused by the failure to perceive the obstacle during the maneuver.
- The pilot's reconnaissance of the area was incomplete, as the seven-meter-high lines were not detected.
- A contributing factor was a lapse in attention as the pilot reached the end of the spraying session.