What happened
On February 19, 2002, an Eurocopter AS 355 N operating as an emergency medical service (SMUH) flight departed from the Flaine ski resort in France. The pilot had just landed on a ski slope to pick up a patient, loading the injured individual into the aircraft while the rotors were still turning.
As the pilot began a descent toward the valley, the aircraft struck two sections of a cable used for transporting explosives for avalanche control. The impact with the first cable section severed the tail rotor drive shaft and damaged the vertical stabilizer. Moments later, the main rotor struck a second section of the cable, causing the entire rotor head to detach from the airframe. The helicopter subsequently struck the ground with extreme force, resulting in one fatality (the pilot) and leaving the other three occupants with injuries.
The investigation
The BEA investigation focused on the flight path and the visibility of the obstacles. Investigators examined the wreckage and found that the engines were still producing power at the moment of impact, ruling out mechanical failure. The investigation also reviewed the pilot's recent history, noting that he had performed a reconnaissance flight in the same area only six weeks prior, during which he had identified these specific cables as hazards.
Analysis of the site revealed that the cables, which were below 40 meters in height, were not marked with any daytime aviation warning markers. While orange and white cones are used to mark these cables during the summer, they are not present during the winter ski season. Furthermore, the cables were difficult to detect visually as they blended into the surrounding pine trees.
Findings
- The pilot chose to fly at a very low altitude during the descent.
- The pilot likely forgot the presence of the cables despite having identified them during a previous training/reconnaissance flight.
- The urgent nature of the medical transport mission may have contributed to the decision to maintain a low altitude and the subsequent oversight.
- The lack of visible markers or warning poles near the impact site made the cables extremely difficult to detect against the forested terrain.