What happened
On September 10, 2009, at 17:45, an EADS Eurocopter AS 350 B2 helicopter, registered F-GIRF, was engaged in a firefighting mission near Le Brusquet, France. The aircraft was equipped with a CONAIR water-bombing kit, including a ventral tank and a pumping system. During the operation, the pilot was maneuvering low over a river to locate a suitable area for water collection.
While searching for sufficient water depth, the pilot descended to a very low altitude along the riverbed. To protect the external pumping equipment, which hangs five meters below the cabin floor, the pilot was closely monitoring the rearview mirrors. After an unsuccessful attempt to refill the tank, the pilot decided to climb and return to the riverbank to consult with the mechanic. During this maneuver, the tail rotor struck an electrical line spanning the river, causing the helicopter to enter an uncontrolled rotation and strike the ground violently.
The investigation
The investigation focused on the reconnaissance procedures and the communication between the crew members. The crew included the pilot, a mechanic, and a water-bombing officer. During the initial reconnaissance of the fire site, the mechanic identified electrical lines crossing the river perpendicularly. When the mechanic asked the pilot if he had seen the line, the pilot acknowledged the observation. However, the pilot later clarified that he believed the mechanic was referring to a different line located within the fire zone.
The investigation also reviewed the operator's manual for special activities. While the manual required a reconnaissance flight, it lacked specific definitions regarding the scope of the "intervention area" and did not clearly delineate the division of tasks between the pilot, mechanic, and officer. This ambiguity led the pilot to conduct a single reconnaissance covering both the fire zone and the water collection area.
Findings
- The primary cause of the accident was the pilot's loss of situational awareness due to intense focus on monitoring the pumping equipment in the rearview mirrors, which led to the failure to detect the obstacle.
- Inaccurate communication between the pilot and the mechanic during the reconnaissance phase contributed to the error, as the pilot misidentified which power line was being discussed.
- The pilot's attention was diverted by the need to avoid dragging the external pump through the riverbed.