Is LED airfield lighting right for your airport?

Is LED airfield lighting right for your airport? It’s a question you may need to ask yourself if you intend to install or replace your airport’s lighting system, and the answer may be easier than you think. For Raleigh-Durham International Airport (RDU), located in central North Carolina, it was a question we recently had to consider and decide upon. This article details the process we went through in considering our answer and the results of our decision regarding light emitting diode (LED) fixtures and supporting systems.

RDU serves as a gateway to the Research Triangle Region of North Carolina. Situated halfway between the cities of Durham and Raleigh, the airport serves a community of over one million people and over nine million passengers per year. The region is home to the world-renowned Research Triangle Park, major colleges and universities, as well as some of the preeminent medical facilities in the country. Ten major airlines offer nearly 200 daily departures to 35 domestic and international destinations.

By 2006, RDU was fast approaching the tipping point for maintenance costs related to its aging airfield electrical systems, both in the electrical lighting control vaults and in field circuits and fixtures. Numerous circuits were in extremely poor condition, with most near or even beyond their useful life. There seemed to be no end to the yearly increases in the cost of maintaining the in-place systems. Something had to be done and in reasonably short order.

We knew we had to replace our current lighting systems with something that would provide us the function, economy, reliability, and service longevity we demanded. But what technology offered the best solution in our airport’s situation? We began looking into the current systems and components in the marketplace that would both meet our needs and were approved for use by the Federal Aviation Administration (FAA).

A newly installed LED elevated runway guard light

In 2007 RDU contracted with Delta Airport Consultants to assist us in choosing, then designing, a new airfield lighting system. It quickly became apparent to the airport that LED technology held merit and was fast becoming a major player in the airfield lighting market. It certainly seemed environmentally and economically friendly on the surface, but was it proven and was it reliable? A study of such systems by Delta was given top priority.

As an airport, RDU was willing to explore new ideas and technology if it had a high probability of success. In the end, Delta Airport Consultant’s research showed great promise for LED technology and proven performance in the circuits already installed at other airports around the country.

With the research completed, the RDU team decided that LED lighting technology was the best choice for our airport. System design then began in earnest. Every LED lighting type currently approved, or expected to be approved by bid time by the FAA, was included in the design, including all airfield guidance signs. Also, due to the numerous problems experienced with older equipment in the airfield lighting vaults, RDU included replacement of the old circuit regulators with new ‘plug & play’ technology power packs. These solid state units promised superior reliability, constant system monitoring and reduced maintenance headaches.

Another very important element of the work involved a state-of-the-art upgrade of the existing airfield lighting control system (ALCS). With the new technology, the air traffic control tower and the maintenance shop would have ‘touch screen’ control of airfield lighting, with the entire control system riding on the airport’s information technology (IT) system backbone. It was a rather bold move to use the airport’s IT infrastructure to carry the ALCS control system communications, and a break from the traditional ‘closed’ communications system for the ALCS. The design and implementation of that approach required very close coordination between the FAA, the airport’s design team, the contractor and system manufacturer and several internal RDU departments.

Lastly, the existing control and power cables in the field had been installed with multiple circuits passing through the same junction cans. According to Ron Jewett, the airport’s Facilities Engineering Manager for the work, the old layout had presented many problems and added to confusion during maintenance activities, therefore we wanted to provide the best maintainable system possible in the new design. “Together with our Maintenance shop and Delta, we devised what we called ‘intelligent junction can plazas’ that allowed our circuits to be separated at all junction points.”

This feature allows RDU to isolate work on the circuit in need of maintenance. This also eliminates any confusion for maintenance technicians in the field regarding which circuit they are working on. It is also a real benefit for the airport operations team, since multiple sections of the airfield lighting system no longer need be turned off to work on a single problem circuit. This keeps taxiing aircraft moving on pavement that would otherwise have required a closure.

Making the decisions regarding the type of lighting system to be used and associated design choices was one thing, but RDU also had to find funding to get the work started in a time period when the US economy was heading for, and then entered, a recession. The estimated price tag exceeded $22 million US dollars, with the total actual bid cost coming in at just over $20 million. Without help from outside funding sources the project would have a tough time getting off the ground.

Like most US airports, RDU turned to the FAA’s Airport Improvement Programme for a portion of the funding. The entitlement funds we earned under the programme paid for 41% of total construction. In addition, we were awarded American Recovery and Reinvestment Act grants covering another 29%. Finally, a grant from the State of North Carolina paid another 12.4% of the tab. In the end, RDU contributed just over $3.5 million of its own funds to get all of the work done.

We felt very fortunate indeed to have been able to capture the bulk of the funding for this work from federal and state sources. It made this necessary lighting replacement project a reality. But obtaining the funds wasn’t easy by any stretch and took a considerable amount of hard work, planning and the coordination of numerous agencies to make sure the funding was secured. One thing we’ve always had in our corner is the solid working relationship we’ve formed with both the FAA and North Carolina’s Division of Aviation.

The work was divided into two major phases consisting of the east and west side of the airport. Phase I of the work was bid and construction began in the spring of 2008. The first LED circuits were completed by late summer of that year, with phase I wrapping up in the spring of 2009. This phase resulted in the installation of over 800 new LED lighting fixtures and signs, new circuits/wiring on the east side of the airport, new east side lighting vault equipment and a fully updated airfield lighting control system.

All airfield electrical work was performed by Barnes & Powell Electrical (B&P), Elm City, North Carolina, with not a single change order issued during the work. According to James Powell, Vice President of Barnes and Powell, the airport project was a challenging one. But in his words, “RDU is our home town airport and we did our best to do a quality job for them. What made the entire effort a success was the willingness of all parties, including the designer and the owner, to work together to quickly solve every problem situation!”

They did a superb job for RDU. It really pays to have a contractor you can count on and a great working relationship with that contractor on any job, but it’s particularly important when the construction involves life-safety systems such as airfield lighting. You can’t afford to make a mistake and none were made by B&P.

During phase I, RDU also developed a sound relationship with the equipment manufacturer for the work, ADB Airfield Solutions (formerly Siemens Airfield Solutions). Being the first to install some of the LED fixtures provided by ADB in the US, we expected more than a few problems to come our way. To our relief, very few developed. Those minor issues encountered with a couple of fixtures during the installation work were resolved by their engineers and project team in quick order, keeping the work on schedule and within budget. Throughout the project, RDU and ADB formed, and maintained, a strong partnership as a result of working on a project where leading edge LED technology was deployed. ADB never failed to tackle any problem, no matter how small, and provided the fix with no hassle and without additional cost.

Phase II work was bid in early 2009, with Barnes & Powell Electric the low bidder in June of that year. The work is currently underway with no major problems and is scheduled to be complete by late summer 2010. By its completion, RDU will have replaced every incandescent airfield light where an LED fixture is FAA approved. That’s right, every fixture except for runway edge lights for a grand total of 3,200 fixtures. This includes all of the airport’s taxiway edge and centreline, runway guard, touchdown zone, obstruction, runway centreline and runway end identifier lights. In addition all 266 guidance signs and our distance to go signs will be replaced with new signs lit by LED fixtures.

New ‘power pack’ equipment in Lighting Vault 1 serving the east side of the airfield

RDU has also installed all new circuits/ wiring across the airfield. Both our airfield lighting vaults now possess the latest equipment and are working superbly. The vault equipment is state-of-the-art, with constant, real-time monitoring and recording of the health of the system. It used to take several man-hours to determine the circuit condition of just one circuit; it now takes mere minutes for all of our circuits combined, with maintenance time on the system decreasing drastically overall as well.

We anticipate FAA approval of runway edge LED fixtures in early to mid 2011 and we’ll very likely be the first in line to install those fixtures when approval is received, making RDU very possibly the first airport in the US to go completely LED on the airfield.

Why are we so impressed by LED tech – nology for our airfield lighting? The reason is simple. Based on actual experience, not projections or estimates, the cost of main – taining the fixtures is phenomenally small, pilots are enthusiastic about the quality of the lights, and our airfield lighting system reliability is the best ever.

For example, we’ve had LED fixtures in place now for nearly two years on the east side of the airfield and have not had to touch a single one for preventive or breakdown maintenance purposes. By comparison, we would have attended to our incandescent fixtures at least twice, if not three times in the same time period, just to replace the bulbs.

According to RDU’s field maintenance supervisor, Rickie Bell, every time we touch a fixture we run the risk of damaging it. He continued, “But with the new LED lighting, we’re finding that the hands-on maintenance time has gone to near zero. We’re now able to move our people to work off the airfield and reduce our overall backlog in other areas of the airport. That means we’re able to make more customers happy without increasing our workforce.

At this point we’re not certain what the fixture life span will be, but projections run as much as a decade or longer for the fixtures and much longer for the other system com – ponents. Our current experience would seem to point to a very real possibility that fixture life may exceed expectations, and we certainly hope it does.

From the monetary perspective, the savings we’re realising from reduced airfield lighting maintenance labour and parts costs is over $375,000 per year. When you add to that the savings in electricity use, and less vehicle miles driven to and from the airfield by maintenance crews, we’re seeing a minimum of $400,000 in yearly savings, while at the same time enhancing the airport’s sustainability initiatives. Of course, savings of that magnitude for this medium-sized hub airport certainly make the payback on our portion of the investment very attractive as well.

Did the choice of LED fixtures and systems pay off for RDU? All said and done, we’re extremely pleased with the LED’s. It was certainly the right choice for our airport and its customers.

If you’d like to hear more about our airfield lighting systems, please don’t hesitate to call or drop by for a visit. At RDU, we’re always open to sharing our experiences with others for the betterment of the airport industry on the whole.

About the Author

Steve Pittman

Mr. Pittman leads RDU’s Maintenance, Facilities Engineering, Environmental, Noise and GIS efforts. His experience includes engineering consulting and construction programme management and he is a licensed professional engineer in NY, NC, and TX. Serving in the United States Air Force as an engineering officer, he retired in 1995. He holds a BS in Civil Engineering, and a MS in Facilities Management.