What happened
On July 8, 2016, an Airbus Helicopters AS 350B2 was performing vineyard spraying operations near Benningen am Neckar. During the final flight of the day, intended to clean the aircraft's spraying equipment with water over a fallow field, the pilot was flying from west to east. While flying against the sunlight, the pilot experienced several impacts. Although the aircraft continued to fly normally, a whistling sound was noted.
Believing the landing skid had struck a power line, the pilot immediately returned to a nearby refueling point. Witnesses on the ground reported hearing a series of loud bangs in quick succession. Upon landing, the pilot, who was uninjured, discovered damage to the rotor blades and the cabin roof area.
The investigation
The BFU investigation established that the helicopter had severed four cables, each approximately 2 cm in diameter, belonging to a 20 kV power line running north to south. The impact caused localized power outages in Benningen am Neckar, Freiberg am Neckar, and Peidelsheim, and briefly disrupted river traffic on the Neckar.
Investigators found that the pilot was experienced, with approximately 3,666 total flight hours and extensive experience in agricultural spraying. The pilot was also familiar with the specific flight area and had flown over the affected power lines multiple times previously. The aircraft was equipped with a spraying system but lacked cable-cutter equipment, which is available for this model.
Findings
- The aircraft struck a 20 kV power line, resulting in severed cables and damage to the rotor blades and cabin roof.
- The pilot was flying into the sun, which may have impacted visibility of the wires.
- The aircraft was not equipped with specialized wire-strike protection kits (cable cutters).
- The impact caused significant damage to the aircraft and triggered electrical outages in several nearby communities.