Incident Overview
A Bell UH-1B helicopter operating under a restricted category was performing external load lift operations at a construction site. The helicopter was hovering near high voltage electrical wires while using a 110-foot-long steel cable. The construction project was overseen by the Alaska Energy Authority, a state corporation. According to the state project manager, the electrical wires were energized and configured to de-energize if a short occurred.
Flight Crew and Procedures
The pilot, who possessed extensive external load experience, had accumulated only about one hour of flight time in the accident helicopter make and model. He reported being unaware that the electrical wires were energized. The chief pilot occupied the right seat and stated he was providing guidance during the flight. The chief pilot indicated that he knew the wires were hot.
Sequence of Events
Shortly after the long line was connected to a load of steel beams on the ground, the cable made contact with an overhead electrical wire. This contact resulted in the electrocution of one ground crew member who was standing on the load. The construction project operations manager reported that the electrical short, caused when the cable touched the wire, was insufficient to trip the electrical power off.
Company Procedures and Manual
The helicopter company's external load manual specified several procedures: the chief pilot would brief all personnel on procedures for each operation; the flight crew normally consisted of one pilot; a hand signalman separate from the ground crew should be assigned no other duties during the operation; the pilot could elect to use continuous visual observation of the load, eliminating the need for a signalman. The manual also stated that radio contact between the pilot and the hook-up man was highly desirable, and that a signalman should be present at all times in case of radio failure. If the pilot could observe the hook-up via a skid-mounted mirror and maintain VHF two-way radio communication, a signalman was not required.
Communication and Signalman Status
During the accident flight, direct radio communication between the ground crew and the pilot was not maintained, and a signalman was not utilized.
Investigation
The investigation into the incident continues. No findings of probable cause have been issued at this time.