History of the Flight
On Saturday, 17 June 2017, at approximately 20:30 local time, a Eurocopter AS 350 B3 helicopter, registration F-HETH, departed from the helicopter base in Hoyos, Cáceres, to participate in firefighting operations in Garrovillas de Alconétar, about 30 nautical miles south. The pilot had been on a rest period after a previous fire and was mobilized by the Regional Operations Center for the Infoex Plan. After arriving in the operational area, he dropped off the firefighting squad at 21:25 and proceeded to a nearby reservoir to collect water. After an initial drop without incident, he returned to the reservoir for another water load. While maneuvering, the pilot suddenly observed power lines ahead and executed an evasive maneuver, but the helicopter impacted the wires at approximately 21:29. Following the strike, the pilot performed an emergency landing to assess damage. Uncertain of the extent of damage, the firefighting squad returned to base by ground vehicle. The next day, a company mechanic inspected the helicopter, and it was flown to Serradilla base for a thorough check. On 20 June, the mechanic discovered marks on one rotor blade (the blue blade) attributed to the impact with the lines, which had not been detected earlier. The blade required replacement, and the helicopter was grounded.
Injuries and Damage
The pilot sustained no injuries. The aircraft suffered heavy damage.
Investigation
The investigation was conducted by the Spanish Civil Aviation Accident and Incident Investigation Commission (CIAIAC). The report noted that the water loading maneuver was executed in an area that had not been previously reconnoitered. Contributing factors identified included low visibility at the accident site, the failure to reconnoiter the water loading area, and the absence of lighting on the power lines near the reservoir, which was likely to be used for water loading.
Probable Cause
The investigation concluded that the accident was caused by the execution of a water loading maneuver in an area that had not been previously reconnoitered.