A small group of spectators scanned the sky from the power line cut intersecting Tuttle Hill Trail in Antrim on Tuesday morning, eager to see Eversource’s first trial of a new technology. The onlookers, Eversource staff and tree trimming professionals, watched a helicopter come into view, dangling a huge saw on a 90-foot line. The small aircraft positioned itself above the boulder-choked power line cut and deftly swept the saw along the forest edge like a colossal hedge trimmer. Bystanders moved to the far side of the cut as radios squawked and the machine flew over, the pilot’s head visible out the side of the cockpit as he constantly adjusted the helicopter and the 800-pound saw attached. It cut for a couple thousand feet after coming into view before wheeling in the sky towards its refueling station, later returning for additional passes.
It may seem like an extreme way to beat brush back from power lines, but it could play an important role in Eversource’s constant work to keep power lines clear of trees, Manager of Vegetation Management Bob Allen said. The five-mile swath the pilot cleared on Tuesday has been prone to recent tree-related outages, including last week’s Election Day windstorm, when a tree temporarily took out power to three polling places.
“The work we completed in one day using a helicopter would have taken four climbing crews several weeks working by foot,” Allen said. That was especially important this year, since the Northeast had more storm damage than usual, and fewer people to clear it away. It made sense to look for a different way to clear brush in the grid’s most hard-to-reach areas, he said, when anticipating future tree damage due to invasive species like the Spotted Lanternfly, and fewer tree trimmers entering the industry. Eversource doesn’t use herbicides to clear power line cuts in New Hampshire, Allen said, so rocky or steep areas usually require specialized mulchers to shred vegetation under the lines every five years or so, and trees that encroach from the sides have to be hand-cut, with workers coming in on skid-mounted buckets, quads, or on foot, far away from help in case of an emergency. Tuesday’s helicopter tree trimming spectacle was a first in Allen’s 42 years in the industry. He described it as a game-changer, like the advent of the chainsaw in the 1940s.
Rotor Blade, the company Eversource contracted for the overhead trimming, is based in South Carolina and works on railroads, pipelines, utility lines, and even clears trees for army base operations and ski areas, Field Operations manager Steve Davis said on site on Tuesday. Each of their 13 pilots are already experienced flyers when they’re hired, and they undergo even more rigorous training before operating with a running saw. Pilots fly over rights-of-way to scope out the route and obstructions in advance, and they’re in constant communication with a ground crew of ten, who report difficult-to-see hazards like guy wires and deer stands from the ground while the pilot operates the saw from the cockpit. The light helicopters (the same type used in the show Magnum P.I.) refuel every 45 minutes, and a pilot may make two passes on the same stretch of trees, Davis said. Crews stopped traffic whenever the helicopter flew over nearby Route 9, he said, and ground crews would later take care of the cutting immediately adjacent to roads and occupied buildings, he said. Tuesday’s run was likely the last the company will do in the Northeast for the winter, he said: high winds, low visibility from clouds, and low temperatures in the open cockpits are no good for flying.
Eversource plans to explore expanding the technology in other remote areas with rocky terrain in their three-state coverage area, representative Kaitlyn Woods said.