Negotiating the Fly by Wire
By Carroll McCormick
High above the ground, bundles of glass insulators swing from decades-old U-bolts dangling from towers carrying 500,000-volt power lines.
By Carroll McCormick
High above the ground, bundles of glass insulators swing from decades-old U-bolts dangling from towers carrying 500,000-volt power lines. Hydro One, Ontario’s power utility, spent two months this summer replacing the U-bolts, using two crews of pilots and linesmen in two Airbus AStar B2s. This is just one of the latest of more than 65 years worth of assignments carried out by the power utility’s helicopters.
|Helicopters have enhanced the reliability of the grid and introduced efficiencies to work procedures in many ways.
(Photo courtesy of Hydro One)
The AStars are among 42 helicopters that Hydro One and its previous incarnations have owned since it bought its first machine in June 1949: a Bell 47D1, registration CF-GMQ, for $30,000. Then known as the Ontario Hydro-Electric Power Commission, it was the first utility in North America to purchase a helicopter for power line work.
Over the decades, helicopters have enhanced the reliability of the grid and introduced efficiencies to work procedures in many ways – for example, replacing dog sleds, snowshoes and horseback with rapid aerial access to power lines for scheduled and emergency inspections.
The current fleet stands at eight machines: one Bell Long Ranger 206L, four Airbus AStar A350 B2s and three AStar A350 B3s. Eight full-time and two part time-pilots log about 4,200 flight hours a year working on a vast system that includes 30,000 kilometres of transmission lines and 12,000 km of distribution lines.
“Many of the lines are in the middle of nowhere. The safest and most economical way to service them is with helicopters. This is a very safe and efficient tool,” says John Bosomworth, Chief Pilot, Hydro One Helicopter Operations.
|To work at Hydro One, pilots need a variety of skills. (Photo courtesy of Airbus Helicopters Canada)|
Accessing much of the system is “brutal,” as Bosomworth puts it, revealing one of the beauties of using helicopters. In the old days, just walking the rights of way to inspect lines was a lifestyle as much as it was a job. For instance, says Bosomworth, “On the power line between Ear Falls and Pickle Lake, which has 2,290 poles, it was so slow and so difficult there were full-time linemen who lived on the lines. They had four hydro houses on that line. They walked the line 12 months of the year and overnighted at remote huts.”
Airborne inspections, on the other hand, can proceed at 65-80 km/h for smaller structures up to 18m high, and as quickly as 95-115 km/h for the 31-m high, steel lattice towers that carry the 500 Kv circuits. Pilots can hover while an inspector studies every detail of a tower’s condition. High-visibility windows made by Airbus Helicopters Canada can be fitted onto the Astars for low-level patrols.
Hydro One has adopted multiple technologies to enhance the effectiveness of its helicopter operations. For instance, custom-built, gyro-stabilized infrared cameras can be fitted on the helicopters. They can see heat signatures that indicate potential failing joints and other trouble spots like clamps and insulation strings. “If we can find a fault before it fails, the savings are huge,” Bosomworth says. Capitalizing on the power of the GPS, Hydro One has collected the GPS coordinates of every single structure in the province, which are available in the helicopters on standard automotive GPS units. “We can fly directly from one location to another. It shows the structures on an overlay on a moving map,” Bosomworth notes.
The helicopters do a lot of heavy lifting. Trucks bring poles and other hardware to staging areas as close to a power line as possible and helicopters take over from there. “We might fly poles a couple of kilometres or up to 60 kilometres, one way,” Bosomworth says. The highly-skilled pilots can set poles with great accuracy, lower cross arms into place and string power lines. They also feed strings of insulators down between the wires. “It is like threading a needle,” says Bosomworth.
|Safety is paramount at Hydro One and managing flight safety includes many elements, such as intense training, regular safety meetings, a fatigue management program and more. (Photo courtesy of Airbus Helicopters Canada)
For jobs requiring lifting capacity in the 6,000-kilogram to 7,000-kilogram range, Hydro One hires Skycranes or Chinooks. The utility used to need outside help to lift the 31-m long wooden poles, which weigh in at 1,400 to 3,600 kg, but another in-house development, 1,100-kg composite poles, are within the capability of the B3.
The utility and its pilots have developed several techniques over the years to increase the versatility of the fleet. For example, if a tree has fallen across a power line, a helicopter can remove the tree with a tree hook attached to a 31-m long line. And remember that U-bolt replacement program? The trick there is to hook on to those bundles of insulators and lift them just enough take the weight off the U-bolts so linemen perched there can replace them.
And how do those linemen get way up there? By going down a set of stairs, as strange as that sounds. Hydro One’s slickest in-house development, which it calls the AirStair, is a set of steps that can be attached to the side of a helicopter. The pilot sidles up to the end of the arm of a steel tower and hovers there while a lineman steps off the AirStair onto the structure. Later, the pilot comes back and the lineman climbs aboard the helicopter via the AirStair. For quick jobs linemen can work from a little platform at the base of the steps.
|Eight full-time and two part-time pilots log about 4,200 flight hours a year working on a vast system that includes 30,000 kilometres of transmission lines and 12,000 km of distribution lines. (Photo courtesy of Airbus Helicopters Canada)
Bosomworth describes the AirStair, the training and the flying. “It took about six years to develop this process in house,” he says. “We have two AirStairs. It is the most documented process in Hydro One. The training we do is very complex. There is classroom work, exams, training, monitored rides and workplace inspections. The AirStair is the pinnacle of the flying we do. We have done about 40,000 on/off operations in the 12 years we have operated the AirStair.
“The close proximity to the wires is the most highly skilled part of this,” Bosomworth says. “The visual cues the pilots get from seeing the structure less than one metre away are quite good. If you ask a pilot to hover near a stump, he can do it. The mindset with steel and live wire is different, however, but the skillset is the same. The attention required is 100 per cent. Transport Canada limits the wind speed to 30 knots for using the AirStair, but we rarely get up to that. We are also conscientious that we do this safely. We sometimes have the wind off our nose, sometimes off the side, sometimes a tailwind. Each pilot has his comfort zone as to when to stop flying. We encourage them to err on the side of caution.”
Flying around wires as one’s bread and butter is highly specialized work. “I call it ‘sleeping with the enemy,’ ” Bosomworth says. Only high-hour pilots need apply to Hydro One. An applicant needs at least 3,000 hours of utility operation (not a power utility); e.g., bush work, significant Astar time, and excellent slinging skills.
|Hydro One has adopted multiple technologies to enhance the effectiveness of its helicopter operations. (Photo courtesy of Hydro One)
Once on the payroll, pilots will spend four months getting familiar with the power network before they are let loose around power lines in a helicopter. Hydro One teaches them the specialized skills they need, and certain maneuvers are restricted to the more seasoned pilots. “We do have some limitations of who does some tasks; for example, a pilot has to have been flying here two years full-time before he can do AirStair work,” Bosomworth says.
Flying in a wires environment is unforgiving. In 2007, for instance, a pilot attempting a landing in an Aerospatiale AS350 B2 struck a guy wire 31 metres above the ground with his main rotor blades. “We work in close proximity to power lines. We land under them. They totally disappear in some situations. If you are flying along a transmission line, if an intersecting line runs under them, no problem. If it runs over the line, it would be a problem,” Bosomworth says.
The pilots are taught about high-risk times, such as late afternoon near the end of a long day of flying in hot weather. Linemen and technicians are taught to point out hazards to their pilots, that it is never wrong to do that, and not to assume that the pilot sees the hazard already.
The in-house training is demanding. For instance, says Bosomworth, “In slinging poles there are a variety of ways of doing it. Putting them in sono-tubes, lowering them between three wires that are two feet apart, lowering a 15-inch diameter pole through a 24-inch gap. We practise slinging, AirStair work, delivering cross arms and flying around in the wire environment. We do very complex slinging. It is one of our highest risks.”
Managing flight safety includes many elements, such as intense training, a company aviation safety officer, regular safety meetings, an in-house specific fatigue management program and an acute sense of safety in a work environment that is inherently dangerous for most front-line employees. “One can’t forget our maintenance department under the direction of Rob Tapper. Our maintenance is second to none,” Bosomworth adds, “It plays a huge role in our safety program.
"[This] is the culture of a very progressive company. If people have safety issues, they bring them forward. There are a lot of rules we review before each flight. The element of complacency in your work environment will always pop up, but the last thing we say [before taking off] is ‘do not be complacent.’ ”