Hydro One (and its predecessor Ontario Hydro) has maintained a fleet of helicopters since June 1949, making it one of the oldest commercial helicopter operations in North America. This fleet provides invaluable support for the growing demand of Hydro One's expansive and sometimes-inaccessible power grid.

To further enhance the helicopter program, John Bosomworth, a Hydro One pilot, conceived the AirStair, a device attached to a Eurocopter AS-350B2 A-Star helicopter for transporting power-line workers on and off the towers and structures. The transportation device, design-built by an aircraft engineering firm and line maintainer crews, reduces tower climbing and ground travel time between structures.

Flying from Site to Site

Inspection of structures and equipment, which is ongoing at Hydro One, is an area where even greater time savings have been realized with the AirStair. An example of this was illustrated during the recent insulator testing program on the Bruce to Milton B561M 500-kV circuit in the western greater Toronto, Ontario, Canada, area. Working in five two-man teams, each team (and their equipment) was delivered right to the structure peak from the helicopter. The team only needed to climb up and down a few feet from the top to the insulator locations. While the first team was performing the inspection, the second, third, fourth and fifth teams were delivered to the next assigned structures. As work was completed, the helicopter returned to each location to pick up and leapfrog the teams along the lines.

This program encompassed the testing of approximately 100,000 individual insulator skirts and would have been very costly and, especially in the many cases where the line crosses sensitive areas, railways and other issues, may have been almost prohibitive.

Staying Safe

During transport or when positioned on the AirStair, the line maintainer uses a travel restraint system (a full-body harness and fixed-length lanyard) that will not allow travel off the AirStair. During on-and-off transfer from the device, line maintainers use the Wishbone Safety Device as part of their fall-protection assembly. This device allows personnel to keep their fall-protection system anchored at all times. When properly attached to a line maintainer's harness, its design will allow the safety device to release from the moveable anchor point (the aircraft) while maintaining connection to the fixed support (the structure). Should the helicopter inadvertently move during aircraft to structure transfer (while the worker is connected to both the structure and the aircraft), the device will release (separate), preventing the worker and body harness from being pulled between the two attachment points.

Regardless of the terrain, environmental sensitivity and ground inaccessibility, Hydro One line maintainers find a way to get the job done. To date, the AirStair has been used to perform approximately 6000 “on and offs.” Its use has steadily grown to become a successful, safe and efficient part of maintaining the company's towers and transmission system. Crews report that eliminating the need for ground travel from one structure to the next, climbing up and down the structure, and minimizing the belting and unbelting, has greatly reduced the fatigue factor, not to mention the amount of time it takes for line maintainers to perform their work.

Jeff Pellar is a journeyman lineman and work methods specialist at Hydro One in Ontario, Canada, where he has worked for more than 18 years. He serves on several Canadians Standard Association committees and is a member of the International Society for Fall Protection. j.pellar@hydroone.com