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• Flight Today

High Tension

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

• By James R. Chiles
• Air & Space Magazine, March 01, 2001

To some people, it would be cause for much grief, this Hughes MD 500 helicopter sitting in the hangar, rotor blades snapped, tail boom sheared off, Plexiglas cockpit nose broken. Repairs will cost at least $160,000.

But to Darryl Ed, president of Haverfield Corporation of Gettysburg, Pennsylvania, a helicopter company that maintains power lines, it’s nothing to mope about. He says the fact that the two men on board walked away largely unscathed was due to world-class piloting—under the circumstances.

The circumstances were this: Pilot Dennis Anderson’s job that day last April was to hover the MD 500 a few inches from a live 230,000-volt power line west of Chicago so that an electrician sitting on a platform on the side of the helicopter could work on the line from the air. The helicopter’s rotor blades overlapped the power line. The Allison turbine engine quit suddenly, leaving the rotors spinning only from inertia. In the second or two before the Hughes settled enough to put the rotors into the power line, the lineman disconnected his equipment from the line. At the same moment, Anderson banked the aircraft sideways. It whirred toward the ground a hundred feet below, gathering speed.

When an engine quits, helicopter pilots wish for a surfeit of altitude or speed. In an unpowered descent—called an autorotation—either will allow the free-spinning rotor to build up enough rpms for the pilot to soften the landing by pulling up the collective lever at the last moment. This causes the rotor blades to dig into the air and slow the descent. But when an engine quits at 100 feet, the options are few.

Anderson aimed toward a patch of swamp, the softest spot in the immediate area. The MD 500 hit the ground so hard the rotor blades bowed downward and chopped off the tail boom. The front of the skids sank into the mush, leaving the helicopter in a showy headstand. It was a fortunate anticlimax. Anderson had missed the power line and even saved the helicopter fuselage. It was not a routine day, but little is routine in the live-line bare-hand maintenance business.

The U.S. power grid has nearly 160,000 miles of high-tension transmission lines, each line carrying 230,000 volts or more. Sooner or later such lines need attention, which might entail changing out hardware hanging on the lines, stringing fiber optic cable, or excising  short sections of worn wire and splicing in new.

Big transmission lines usually have three “conductors” consisting of two or more closely spaced wires. The conductors run parallel, separated by 20 feet or so, and hang from bell-shaped ceramic insulators, which are suspended from the arms of steel towers. Previously, linemen climbed up the towers and clambered along the conductors, but this required the power company to shut the power off first. Today, power companies prefer not to shut down transmission lines for routine maintenance, because closing down a 500,000-volt line, for example, can run as high as $50,000 per megawatt hour in replacement power costs.

That’s where helicopters come in, flitting from span to span like big hummingbirds—a sight that often prompts onlookers to call police and report that helicopters are stuck in the power lines. A lineman can perform many operations from a helicopter—while the juice is on. Today, hundreds of crews worldwide are doing “helicopter live-line bare-hand maintenance.” In this country, the work is done by a handful of contractors and by utility companies.

It sounds insane, especially to pilots, who are taught to steer well clear of power lines. Live-line maintenance was featured on the History Channel’s “Suicide Missions” series last year. “TV shows portray this as seriously dangerous work, like lion taming, but that is not at all the case,” says Bob Feerst, president of Utilities/Aviation Specialists, a company that trains crews and audits flight operations for safety. “It’s very safe if the crews follow procedures and the people are trained.” Done right, Feerst says, it’s no more dangerous than working from the bucket trucks that raise linemen to the wires.

Which is not to say that it offers room for mistakes. In the last six years, helicopter live-line maintenance accidents have claimed three lives. “If you factor out deep space and covert military action under enemy fire,” Feerst says, “operating in the utility wire environment is the most demanding flying, by far, and needs the most skill from the pilot and crewman.”

In 1979, Michael Kurtgis was transporting Florida Power and Light employees as the company’s chief helicopter pilot. He considered the time that conventional crews spent setting up and breaking down for even simple power line tasks, and figured that a helicopter could speed things up immensely. He approached his managers and two helicopter manufacturers with the idea of working on live transmission lines from a helicopter and proposed some trial runs, since no one had ever tried flying so close to wires—not on purpose, that is. “They thought I was out to lunch,” he says. Kurtgis resigned to start his own power line maintenance contracting company, USA Airmobile in Fort Lauderdale, and patented his methods, but couldn’t prove his idea would work because no power company would allow him to connect his helicopter to an energized power line—that is, establish an electrical connection between the conductive helicopter frame and power line, equalizing the electrical potential so that whatever—or whoever—touches the line won’t get shocked.

Nearly two years went by before Kurtgis got his chance. In early 1981, USA Airmobile won a contract to power-wash insulators on a 115,000-volt line in Dammam, Saudi Arabia. One day during the job, Kurtgis, ready to start work in a Bell 206 JetRanger, had an impulse: He called over the intercom to crewman Jim True, “It’s now or never.” Out here, there was no one to put up roadblocks. “We’ll never get this kind of chance again,” Kurtgis said.

True asked Kurtgis whether he was really sure this would work. Kurtgis said he was pretty sure.

Nobody in a helicopter had physically connected with a live, high-voltage conductor, and the people that Kurtgis had talked to weren’t sure what would happen. A short circuit from high-tension lines to the ground, perhaps through a fallen tree, is enough to blow the tree apart. Would connecting the line to a helicopter stun the crew, or ignite fumes in the fuel tank? A Florida Power manager predicted that a voltage surge would short out the helicopter’s electrical bus.

Airmobile crews had already worked close enough to energized lines to learn that protective clothing is a must. Kurtgis had a close encounter with a 500,000-volt line before he had even tried to touch any energized lines from a helicopter. “It was like a whole bunch of fire ants were biting you,” he recalled. What had bitten him was “induced current.” High-voltage power lines create a very strong electromagnetic field that reaches far beyond the three conductor wires. This field is not so much a byproduct of the current as a carrier of the current itself. Anyone in the immediate vicinity, like the pilot in a hovering helicopter, is in this field and will feel an induced current along his skin regardless of whether he touches the power line. The sensation is itchy at lower voltages and distinctly painful at higher voltages. Kurtgis learned that a suit of conductive clothing—Nomex fabric with a weave of 25 percent fine-mesh stainless steel wire—allows the  current to flow around the skin.

When Kurtgis sidled the JetRanger close enough, True swung the conductive metal boom of the power washer over to the 115,000-volt power line, causing an arc and the attendant buzzing noise as the arc hit the boom. The arc jumps because the helicopter has a different electrical potential than the power line, and the voltage wants to jump across the air gap to equalize them. Even though he expected an arc, True yelped in surprise, but they were still in the air. Once that connection was made, it was easy to “bond” to the line—attach a cable from the helicopter frame to the line to maintain a good electrical connection between the two. Using such techniques, crews have connected the frames of their helicopters to power lines carrying a million volts.

I met up with Kurtgis last August at a power line training facility operated by American Electric Power near South Bend, Indiana. Performing for a small group of electric-utility maintenance managers, Kurtgis’ crew took a Bell 206 JetRanger through its paces: power-washing insulators to blast off dirt that can cause a short circuit to the tower, hanging a big orange plastic ball on the topmost wires to warn off aircraft, and bolting on spacer brackets that keep parallel wires from chafing each other in the wind.

Much live-line maintenance work involves a lineman sitting on an aluminum platform suspended from the helicopter frame. From this perch, sitting just below the pilot, the lineman has a better reach and posture than he would achieve by leaning out the helicopter door (and the pilot can easily keep him in close sight). It also provides a secure mounting for his generator or air compressor for power tools. Under federal aviation regulations, such an external load puts a helicopter in a restricted category. A crew must be able to jettison the platform in an emergency and therefore cannot hover over occupied buildings or congested areas while carrying it. A lineman working from a platform connects his safety harness to the helicopter rather than to the platform.

In some cases the lineman hangs 50 feet or more below the helicopter at the end of a string of “hot sticks,” rigid fiberglass rods. Since fiberglass does not conduct electricity, the pilot can drop off the lineman at places that the helicopter could not safely approach.

Airmobile’s chief pilot, Doug Lane, flew helicopter gunships for a year in Vietnam and was shot down twice; on the way to Airmobile he flew freight, did traffic reporting, and shuttled oilfield workers to platforms in the Gulf of Mexico. According to Lane, on top of learning new regulations, power line technology, and his company’s specific procedures, an incoming pilot needs to break through a mental barrier to be willing to bring the lineman close enough to the wire—about eight inches from his chest. “When he first comes in,” Lane says, “he’s saying to himself, ‘I don’t want to hurt this guy,’ meaning the lineman, so he’s keeping his distance from the lines. But everything the lineman does is from the upper body, because he’s sitting on the platform.” At times linemen work with pulleys, clamps, and tools that are too heavy to reach out very far with. “The pilot can work [a lineman] to death in two hours if he stays too far away,” Lane said. “He wants the work right in his face.”

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.

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.

Before I left, Campolong handed me a poem he wrote. It ended: “Next time you turn on the switches without a thought/Remember the guys who are repairing it ‘hot.’ ” And, he could have added, if you happen to see a platform-equipped helicopter hovering inches from a power line, don’t bother calling the cops.