What happened
On June 2, 1999, at approximately 18:30, a Bell 47 G2 helicopter, registration F-GFGK, was performing aerial spraying operations over a vineyard in Vauxrenard, France. The mission involved applying sulfate to a plot of land that was intersected by a medium-voltage power line consisting of three cables. At its lowest point, the line hung approximately ten meters above the ground.
During the third pass of the spraying operation, the pilot was navigating a section of terrain that transitioned from an upward slope to flat ground. As the helicopter passed through the lowest point of the power line's arc while ascending the slope, the tail rotor struck one of the cables. This impact caused the helicopter to crash into the ground. The pilot sustained injuries in the accident, and the aircraft was destroyed, though only minor damage was reported to third parties.
The investigation
The investigation focused on the flight path and the pilot's interaction with the environment. Meteorological conditions at the nearby Mâcon aerodrome indicated good visibility (over 10 km) and light winds. The pilot was experienced, with nearly 3,000 total flight hours, including significant time on this specific aircraft type. The investigation also noted that the pilot had been flying in two shifts that day, with a break in operations due to a thunderstorm.
Findings
- The primary cause of the accident was an erroneous assessment of the environment by the pilot.
- The tail rotor made contact with the power line cables during the maneuver.
- The terrain's slope contributed to the difficulty of maintaining safe clearance under the cables.