Nov 30 2012

Utility - Life on the Line Posted 11 years 170 days ago ago by Admin

UTILITY - Life On the Line
By David McColl

Electrical utilities are constantly trying to keep up with ever increasing United States demand.  Currently there are about 160,000 miles of electrical transmission lines 110Kv and above on the nation’s expanding grid.

Helicopters provide a unique working platform with which to perform construction, maintenance, and inspection services. They can complete certain work faster and more efficiently than a ground crew. In many cases the helicopter allows for power lines to be worked on without disturbing the flow of electricity or the surrounding environment.

There are a select number of helicopter companies in the United States that perform power line work, and even fewer that will work on energized lines. These companies supply construction, maintenance, inspection, and emergency services to the entire North American transmission grid.

The Aircraft

The MD 500 series is a very popular aircraft for power line work. It’s compact design, surpassed stability and excellent power-to-weight ratio make it a perfect candidate for flying “inside the box.” This is a term commonly referred to when aircraft are flown between the wires, usually on large voltage lines. This type of environment is where stability and compact size are crucial factors in ensuring the safest possible operation of the aircraft. The comparatively low operating costs and ease of maintenance makes the MD500 the obvious choice for most utility operators specializing in power lines.

The egg shaped designed fuselage has a center beam. The forward seats and restraining harnesses are mounted to this center beam, which has a “roll bar” design that makes the MD500 one of the safest airframes in the helicopter industry.

The flight controls are connected to the control surfaces through bellcranks and push rods. There are no hydraulic controls, so flight controls are not overly sensitive compared to an aircraft with hydraulics. Utilization of the trim is essential for precise flying.

Services

Airborne power line utility companies offer a variety of services to support the electrical transmission industry.  These include new construction, maintenance, inspections, working on energized lines and offering emergency readiness and response to disasters.

With the constant growth and expansion of the electrical transmission industry, the need for new construction can be simplified and expedited by the utilization of helicopters. Positioning poles, pulling sock lines, hanging insulators, attaching support structures, hanging marker balls and bird diverters are just a few of the tasks that can be performed utilizing a helicopter.

Maintenance such as cross arm change outs, spacer replacements, dead-end replacement, insulator washing and splices can be performed swiftly using a helicopter. Transferring linemen to structures then delivering tools and hardware through the use of long lines expedites the process. There is no need to position bucket trucks and cranes as the helicopter can perform similar functions to both.

Working on energized lines adds to the challenge of flying and working in the wire environment. Cross arm change outs, spacer installation, dead-end replacement, insulator washing and splices on the conductor can all be performed while electricity is flowing. When working on energized lines, conductive suits need to be worn to properly protect the lineman and pilot from electricity. Linemen bond the helicopter onto the conductor and bring the aircraft and crew to the same electrical potential, therefore enabling the ability to work safely on the wire.

Pulling rope entails utilizing the cargo hook mounted on the side of the helicopter in which the Pilot In Command is sitting. Rope is positioned and fed through rollers attached to the structure that facilitate the actual conductor wire being pulled. Pulling from the side of the helicopter is a class C load.

Inspection work may involve the addition of cameras and data recording equipment attached and loaded in the aircraft. High definition, corona, and infrared cameras can be mounted on the nose or under the belly of the aircraft.

Changing the configuration of the aircraft will change its weight and balance. These computations need to be updated and reviewed to assure the aircraft is being operated within acceptable limits.
 
Emergency readiness and response is also part of the inventory of services that these specialized companies offer. Hurricanes, ice storms and other natural disasters can severely interfere with the power grid and lives of the population in that given area. In the aftermath of disasters, power must be reestablished before communities can return to some sort of normality.

Benefits of Utilizing a Helicopter

Utilizing a helicopter has environmental benefits. Power lines often run through wetlands, wildlife sanctuaries, waterways, mountains, and other rugged terrain where access is impeded. The helicopter can access these areas leaving a smaller footprint compared to wheeled or tracked vehicles.

Compared to a ground crew, helicopters can significantly faster accomplish tasks such as pulling a sock line or changing out insulators. The ability to deliver linemen directly onto the wire or structure and then long line tools and hardware to them saves time.

Challenges

Challenges include working on dated lines and structures, deployment, administration, limited airspace, natural obstacles, security, and weather.
 
Before deploying an aircraft, the pilot is responsible that all aircraft equipment and job specific equipment is onboard and serviceable.  All paperwork must be completed and any needed plans must be stowed.

Working on old, decrepit structures damaged by either the elements and / or wildlife can present special challenges. Some structures may be unstable to place linemen on due to woodpecker holes, termite damage, and rusted or corroded attachment points.

When working within class B and C airspace, courtesy telephone calls to Air Traffic Control advising them of the job location and hours can make it simpler to operate in these airspaces.

Mechanics face their own challenges.  The security in an uncontrolled airport differs from a class C airport and this can create a difficult environment for performing maintenance. Some airports require escorts and/or have set hours of operation that can hinder the mechanic in his tasks. Uncontrolled airports are more desirable to operate from, as they are generally more hospitable.

Weather can be challenging for any flight but human factors associated with the environment can add challenges to the job.  Most work is conducted in a “doors off” configuration.  This is generally not a problem during the summer months, but during the winter cold can take its toll.  Pilot and crew must be properly dressed to withstand temperatures and wind chills that can drop below zero.  It is common wintertime practice for pilots to take a bag containing cold weather and rain gear. During the summer months, maintaining hydration and avoiding sunburn will help keep a safe and pleasant working environment. Depending on the time taken for the job, bottles of water may be long-lined in a canvas bag to the linemen so they stay hydrated. All seasons require pilots and crew to prepare for environmental factors.

What Ifs?

What if there is an engine failure? What if there is a governor failure? What if the hook fails? The list is constant. The way most of these “What ifs?” are mitigated is through proper flight and job planning. Dissemination of information is essential.  A thorough maintenance schedule and meticulous pre-flight and post-flight inspections are critical as is proper fuel management.  Equally important is having everyone on the job look out for one another.

Training

Training is an essential and required investment in maintaining safe operations. When time allows, pilots are encouraged to practice their emergency procedures and maneuvers. Flying in the wire environment, external load, vertical reference, transferring, and working on energized lines all require training. Other training specific to working on power lines and with ground crew is also conducted.

Collision with wires is a major cause of helicopter accidents and fatalities. Proper crew resource management and knowing how and where to look for wires are essential skills.

Zero-speed autorotation training to simulate an engine failure next to a wire is important.  The aircraft needs to be banked to the right slightly, so that the main rotors will clear any wires below, and then leveled. This emergency procedure is generally practiced at 500ft in an open area, giving time for recovery and to locate forced landing sites.

Practicing emergency procedure when the aircraft is operated under different configurations is essential, as the characteristics will change. An aircraft with the boards on will react different when in autorotation.

Long-lining is an essential skill for operations in utility flying. A new pilot needs appropriate training, mentoring, resources, and opportunities to become proficient with long-lining.

The electrical transmission industry is constantly expanding, and with constant expansion comes the need for constant construction, maintenance and inspection. Helicopters provide a unique and efficient ability to perform this type of work. Companies are always looking for assets and staff that will benefit the industry and team both financially and professionally.

One common trait among quality employees is that they all place an emphasis on safety. A safety culture attitude, accompanied by teamwork and scrupulous training, are the essential for getting the job done right.