Helicopter-supported highwire act keeps the nation’s juice flowing

 - January 9, 2008, 8:32 AM

They’re the unsung heroes of the highwire, the workers who straddle live high-tension transmission lines, wires literally sizzling with their lethal load. Suspended in midair by a helicopter, stabilized by the rock-solid hand of a steady-hovering pilot, line crews would be hard-pressed to repair aging powerline infrastructure as quickly or as well in isolated areas.

“You hunting beah?” the earnestly smiling Chinese gentleman asked Jeff Pigott, aerial line foreman for AgRotors.

It takes a couple of thickly accented repetitions before Pigott understands what’s being asked of him. “He wants to know if we’re hunting bears,” he tells other members of his crew. Understandable. Pigott and his three team members are a rough-and-ready lot who look like they’ve come to the woods and valleys of Sullivan County, N.Y., with serious work in mind. Turning back to the visitor, he reassured him, “No, sir, we’re not hunting bears. We’re working on the power lines for the electric company.”

As an aerial line foreman for AgRotors, Pigott is used to being asked unusual questions. After all, to the uninitiated, the ground and air operation he heads up looks a little threatening–a late 1980s-vintage Hughes 500D flying what looks like top cover for a big panel truck with an aircraft-style refueling rig and nascar- style supply trailer in tow. Navigating by whatever topological map is available augmented by GPS in both vehicles, Pigott stays in constant radio contact with the 500D as it flies to the next power-line repair point. In these days of homeland security jitters and war scares, such an entourage draws crowds wherever it stops.

Just what portions of this ±150,000-volt high-tension line need to be repaired was
determined a few weeks previously via a low-altitude inspection by AgRotors crews flying a 500D armed with open doors and a pair of high-powered gyro-stabilized binoculars. What they were looking for on this line were cracked and decayed crossbeams on the tower structure. Made of wood, these beams were succumbing to the effects of heat and cold, dry and wet, and were cracking. One dark and stormy night, one would fail, throwing the tower’s structure disastrously off balance and bringing the lines crashing to ground just when people most need heat and light. With the suspect structures pinpointed (using a combination of GPS references and a catalog of tower locations), the crews return, as they have this gray, overcast Sunday morning, to replace the old, weathered wooden crossbeams with hollow-steel. Slightly heavier, they are immensely stronger. And they won’t rot in the weather.

But someone has to hoist these beasts some 80 to 100 ft in the air, unbolt the old structure, haul it down the mountain, trade it for the steel replacement, then haul that 10-ft piece of metal into the sky, and bolt it in place. All within inches of bare steel and glass insulators conducting 150,000 volts. Other lines on other days carry more juice, as much as 750 kilovolts. On other days the wind is trickier. This isn’t an especially tough day. But like every other day for this four-man team, it’s a day that begins with safety.

A Flying Ironing Board
Both linemen review the tools of their trade. The suite of equipment used is straightforward enough–a sort of aluminum-mesh ironing board was bolted to the Hughes 500D’s skids back at AgRotors’ Gettysburg, Pa. headquarters. Workers sit at whichever end of the board that best suits the mission at hand; pilot Eric Carroll can see them in either position, which is important. However, the outside man must choose his workstation well in advance, since a Honda gasoline-powered generator (providing electricity for any needed power tools) takes up the other end of the platform and restores lateral balance.

One of the most exotic pieces of equipment used aloft appears to be the most ordinary: pants and a coverall top made of what feels like conventional Levi’s-weight denim washed often enough to give it that broken-in pliability that makes it your favorite pair of jeans. Except that this “denim” isn’t cotton; it’s a blend of 75 percent Nomex and 25 percent stainless steel. Wearing this, an aerial lineman suspended aloft on a hovering helicopter is not grounded; the circuit of which he is a part is not closed, hence no damage from the monumental amounts of current often passed through both man and machine.

“The rationale behind this technology is that the lines can stay hot while they’re being worked on,” explained Pigott. “With the demand for power what it is today, no electricity provider can afford to shut down a major transmission line for very long. Between the heavy use a line endures in the summer, and the damage it sustains in the winter, the relatively light usage seasons of spring and fall give us the best window for repair.”

What’s it like to have a few hundred thousand volts pumping through your clothes (and you) while sitting, safety-belted to a glorified steel-mesh ironing board that’s part of a single-engine helicopter hovering a few dozen feet off the ground? “It’s not so bad,” answered Ken Black, a veteran Skoal-chewing, formerly groundbound lineman who worked for a local Pennsylvania power company. “You can get killed whether you’re more than 10 feet off the ground on a helicopter platform or in a cherry-picker bucket working off a truck. The electricity is the same and so is the gravity. The difference is how you get to the job.”

“You just take it real easy, stay with what you’re doing, follow procedure and keep everything organized,” said helo lineman Duane Wilbur, another former power company line-maintenance tech. A few years ago, Wilbur paid the price for a moment’s inattention, inadvertently touching a grounded insulator on a high-capacity line and, for an instant, becoming the conduit for the greater part of 350,000 volts.

“There was no pain,” Wilbur recalled. “At least not right away. Instead, every muscle in my body, including my heart, tensed simultaneously. I tried to move but couldn’t. It was only when the pilot saw I was in trouble and backed me off the wire that I collapsed in the harness and they could see there was something wrong with me. Some artificial respiration and prompt treatment for the shock and I was back on the job in a couple of weeks.”

Wilbur credits this sort of close crew coordination with saving his life. “We work within inches of each other, in a business with extremely tight tolerances and narrow margins of error every day. You learn to read inflections in each other’s voices, or the intensity with which a hand gesture is made.”

‘Ouch’
It’s about 9:30 a.m. on a power line a few miles from the out-of-the-way Catskill Mountains hamlet of White Sulphur Springs, N.Y. Pilot Carroll has jockeyed Wilbur to within about three inches of the end of a massive wooden crossbeam off a 120-ft-tall tower. Wilbur is in the process of detaching one of the tower’s reinforcing crossbeams, strenuous labor requiring plenty of elbow grease applied to some heavy tools to loosen bolts and fasteners. Carroll holds a rock-solid hover, even in the face of a freshening morning breeze. Gradually, he moves Wilbur in toward the end of the beam, closing a three-inch gap to next to nothing. And beyond. Suddenly, he dances the helo gingerly back and lines it up again while lineman Wilbur readjusts his position.

Later, when asked what had happened, Wilbur explained. “Eric worked me in there tight, which is good, but then it got a little too tight and he was pushing my knees up against the end of the beam. So I said, ‘Ouch’ over our com link and he instantly knew what was going on and pulled back.”

Watching the two men deftly remove beams weighing a couple of hundred pounds apiece, detaching them from the much larger structure and slinging them to earth, only to replace them minutes later with heavier metal replacements, is rather like watching a graceful aerial version of the basic rodeo event known as calf roping. In much the same way that horse and man work together to keep the rope securing the calf taut to the cowboy, Carroll and Wilbur work with helo and lines to use raw rotor power to adroitly move pieces into place.

Asked if there’s a way to subdivide his logbook into flight time in forward flight and that on zero-airspeed flight, Carroll just grinned. “The truth is, I do spend quite a bit of time doing both,” he conceded. “If I was to work it out, I probably would have something like 50/50.” Carroll came to AgRotors the usual way, via the military and then offshore oil in the Gulf of Mexico. “That got old after some years, so when I heard about this I thought I’d come try it out.”

The challenges are obvious. If football is a “game of inches,” then this kind of flying is a game of an entirely different magnitude of difficulty. “When we say ‘hover,’ we mean ‘hover, as in motionless.”

To ease this process, Carroll and many of his contemporaries have cut away the thumbs and forefingers of their Nomex flight gloves, the better to feel subtle variations in the controls’ feedback. “It really is a matter of millimeters. And that’s why this helicopter is the only type I’d try this mission in. The Hughes 500D, with that five-blade rotor, gives us the kind of control and the lack of vibration that no other helicopter can offer.”

Obviously wind is critical to safe operations. General rules bar operating in steady wind exceeding 25 kt, or anything the pilot feels is dangerously gusty. Quartering tailwinds are especially dangerous because they push the tail-rotor turbulence up into the main rotor disk.

Road Show
When the caravan of helo and ground-support truck and trailer come into town, everyone stops to watch and has an opinion, and a question intended to bolster that opinion. On this particular Sunday morning there was, in addition to the man so hopeful that the morning’s mission included bear extermination, some local gentry not surprisingly miffed about the rotorcraft ruckus in the early hours of a Sabbath.
Pigott and his crew had been on the road in southern New York for nearly 10 days, a near fortnight in which their best efforts had been stymied by maintenance problems and poor weather. The contract between AgRotors and the local power company allowed for some weather downtime but less than this job had already called for. After that, it was a flat-rate payment for AgRotors and if the job required more time, so be it. They were working this Sunday morning’s good weather window because they wanted to get home.

Some of the local conspiracy enthusiasts were convinced the Ag-Rotors crew was checking out the area for suspected al Qaeda activity. Even they seemed to accept the more prosaic explanation of the team’s mission. The gang from Gettysburg’s favorite outraged local citizen vehemently objected to the disruption in her weekend schedule that the helicopter represented. She admonished the crew that the next time such patrol and repair work was scheduled, an ad should be taken out in the local newspaper announcing such work. A few minutes of conversation revealed the woman’s true identity: copublisher, with her husband, of the aforementioned local paper.