Helicopter pilots play chicken with high-voltage power lines so crews can work on live wires.
- By James R. Chiles
- Air & Space magazine, March 2001
(Page 4 of 5)
As the crew loaded hardware onto the work platform, Campolong started the MD 500. In two quick flights, he deposited Black and Pigott where the lines crossed a hundred feet above a dairy farm. As Campolong flew off, each man attached his safety harness to a conductor and scuttled spider-like toward a tower. Later, at Campolong’s signal, Schiess donned a set of beige conductive clothing and climbed into the rear seat to watch him work.
The weather was good for power line work: high clouds and only a 5-mph breeze. Campolong offered advice as various situations arose. He suggested that when dropping off linemen on the wires, Schiess get as close as practical to the towers; the further out, the more the lines jump around when a lineman gets on or off. Because placing men on wires near towers is exacting work, Campolong told Schiess he usually did that kind of thing in the morning before the air got hot and winds picked up. Afternoons were good for working out in the center of the spans between the towers. Schiess should beware of a steep hillside, where the wires’ slope would put the rotors at risk.
Crews can operate under a wide range of visual flight conditions. When working from a platform, they can tolerate light rain and even a 25-mph wind if it is steady. Variable winds are acceptable if the “gust spread”—the difference between highest and lowest speeds, is under 10 mph or so. A higher spread can shift the helicopter faster than the pilot can correct. For hanging a lineman on hot sticks that drop through a set of wires, the requirements are stricter: no rain, not even a dewpoint that might cause condensation that would allow voltage to jump from one conductor to another via the moisture. For that reason, crews wipe the hot sticks clean each morning.
After lunch the crew went aloft to begin replacing old spacers on the wires. I borrowed a conductive suit and gloves from Schiess and climbed in the back. The helicopter rose briskly and headed for a span of power line to the south. Campolong matched altitude with the wire and approached it with seasoned confidence. Pigott took a three-foot metal wand connected to the helicopter and stretched it out to the wire, striking a foot-long arc. Holding the rod against the wire with one hand, he used the other hand to bond us to the wire by clamping a cable to it. We were now a part of the circuit, in effect “wearing” the full voltage of the transmission line. From here we could admire the trees, but if we were to contact a branch we’d instantly be electrocuted when the voltage passed through the helicopter to the ground. “You’ve got 230,000 volts flowing around you now,” Campolong said.
Campolong stabilized the helicopter to put the conductor about level with Pigott’s midsection and over his legs. Campolong kept his gaze over his shoulder in Pigott’s direction, sparing only quick glances at his instrument panel and the sky. He made it look easy, but holding a helicopter in midair with only a few inches’ margin of error takes intense concentration. Just a few minutes will exhaust a neophyte.
Whatever the wind direction, the pilot has limited choices about how he approaches the wire. Because visibility is so crucial, he must have the wire on his side, stay clear of other wires, and keep the skids parallel to the wire in order to keep the tail rotor away from it.
Brian Parker of Haverfield, a longtime power line pilot, compares the difficulty to riding a unicycle on a moving walkway while someone flicks the walkway power on and off. Campolong told me, “My mother-in-law asked me once, ‘Why are you so tired? You just sit around at work all day.’ “
In less than half a minute, Pigott, sitting comfortably on his platform, pried off two metal spacers installed 30 years ago when the line was built, slung them under the fuselage, and disconnected the helicopter from the wire. Campolong backed away, moved a hundred feet southeast, and came back to the wire so Pigott could bolt on a new aluminum spacer bracket in a new location. In 10 minutes this part of the span was done and Campolong headed back to the landing zone for more hardware. “Piece of cake,” he said over the intercom.