What happened
On October 14, 2013, an Eurocopter EC1ob helicopter, registration F-HAJJ, was performing a general aviation flight between Boffres and the Antraigues-sur-Volane stadium helisurface. The pilot, carrying three passengers, arrived at the site and performed a reconnaissance flight to inspect the landing area. After landing and parking the aircraft, the crew remained on the ground for approximately two and a half hours.
During the return flight, the pilot initiated a vertical takeoff facing south. As the aircraft began to transition into forward flight, the pilot spotted a medium-voltage power line directly ahead. In an attempt to avoid the obstacle, the pilot applied a nose-down cyclic input; however, one of the main rotor blades struck the cables. The pilot subsequently performed a turnaround and executed an emergency landing back at the stadium. There were no fatalities or injuries among the four occupants, though the aircraft sustained significant damage to a main rotor blade.
The investigation
The investigation focused on the pilot's awareness of obstacles and the accuracy of pre-flight information. Investigators confirmed that prior to the flight, the pilot had been provided with a flight preparation document containing an aerial photograph of the helisurface, which specifically noted the presence of a medium-voltage line located south of the stadium. The pilot acknowledged reviewing this document.
During the initial arrival and reconnaissance phase, the pilot had observed a power line located to the north of the site. The investigation established that the pilot mistakenly believed this northern line was the same one described in the preparation document. Furthermore, the investigation examined the completeness of the site documentation and the pilot's visual scanning during the departure phase.
Findings
- The primary cause of the accident was an incomplete observation of the takeoff sector and a misidentification of the power lines present at the site.
- The pilot confused the power line observed during the reconnaissance flight with the one documented in the flight preparation materials.
- The flight preparation document failed to mention the second power line, which contributed to the occurrence.
- The availability of specific site information may inadvertently decrease a pilot's vigilance regarding obstacles not explicitly listed in the provided documentation.