What happened
On August 8, 2016, an Airbus Helicopters AS350 B3, registration F-HJTB, was engaged in an aerial work mission near Roquefort-les-Pins, France. The flight originated from Cannes Mandelieu aerodrome with the objective of transporting a sling load—consisting of a large bag and iron bars—to a quarry to assist in securing a rock outcrop.
Upon arriving at the quarry, the pilot performed a reconnaissance of the landing site and the area. The pilot had been previously notified of a specific power line in the vicinity, as well as the designated landing and drop-off points. During the reconnaissance, the pilot noted that the ground conditions were likely to generate significant dust during takeoff and landing operations. To minimize dust disturbance, the pilot decided to land directly rather than performing a hover.
After a mechanic attached a 25-meter sling to the aircraft, the pilot initiated a vertical takeoff. During the ascent, the aircraft was obscured by a cloud of dust. During this phase, one of the main rotor blades struck an electrical cable, severing one of the three wires in the line. The pilot subsequently identified the presence of the line and performed an immediate landing.
The investigation
The investigation focused on the circumstances surrounding the contact with the electrical line. The BEA established that while the pilot had been briefed on the presence of one specific power line, a second line, located approximately 100 meters high and slightly in front of the landing zone, went undetected during the initial reconnaissance. This second line was not visible from the ground due to its height and the location of its supporting poles within a wooded area.
Data from the pilot's testimony indicated that the pilot's attention during the reconnaissance was focused on the previously identified hazards and the landing coordinates. The investigation also confirmed that the dust cloud generated during the vertical takeoff significantly reduced visibility, preventing the pilot from detecting the wire before the impact occurred.