High Tension

Helicopter pilots play chicken with high-voltage power lines so crews can work on live wires.

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A crucial part of a new pilot’s training is to ride with a crew, watching how an experienced pilot helps the lineman and vice versa. That’s why Markus Schiess donned his international-orange flight coveralls one August day and joined a Haverfield crew and its MD 500 helicopter in a meadow in the Appalachian Mountains of central Pennsylvania. Schiess’ logbook shows over 5,000 hours hauling logs in Alaska, running low along rivers in Africa to spray pesticide, instructing in light helicopters, and transporting executives in Taiwan. Schiess fit well the power-line personality profile that Darryl Ed, head of Haverfield, had described: meticulous, confident, with a good sense of humor and an enjoyment of life. Daredevils, Ed had said, need not apply.

In less than a month, Schiess would be doing power line work in Chile for Haverfield, and this week was an opportunity to pick up pointers from pilot Mark Campolong and his crew, foreman Ken Black, lineman Jeff Pigott, and data man Craig McCleaf, who tracks work accomplished and notes any power line damage not visible from the ground. Joining them was Al Knerr, a crew chief from Pennsylvania Power and Light, the owners of the line.

At 10 a.m., before operations started, Black called a quick safety meeting. Though his crew had been working on the 34-mile Montour, Columbia, and Frackville transmission line all summer, taking old hardware off and bolting on new equipment, Black went over the basics again. The three conductors carried a total 230,000 volts; they were spaced far enough apart that the helicopter could hover alongside the center conductor. At Haverfield’s request, Pennsylvania Power and Light had set the line to “manual reclosure” so that if anything got shocked it would be only once rather than the three times that would occur as automatic reclosers tried to restore service to the line.

Black pulled out a dog-eared wallet card listing the minimum distances the helicopter needs to keep in this particular voltage situation—eight feet from a conductor when between wires, five feet from a conductor when between a wire and trees—to prevent a short circuit from passing through the helicopter. “Whatever distance it says, we double it,” Campolong added for Schiess’ benefit.

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.

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