Lighting the Way

To help reach its 2015 prediction of a billion passengers travelling on commercial aircraft, part of the FAA’s Technology R&D program is concentrating on taxiway and obstruction lighting.

Many of today’s busiest airports cannot meet today’s peak arrival and departure demands and future traffic increases will only exacerbate capacity challenges. In many cases, construction of new runways will be feasible and helpful, but this approach alone is unlikely to resolve all future challenges. Expanded runway capacity must be accompanied by improvements in areas such as design standards, management strategies, decision support aids and procedures that will allow greater capacity.

Increases in airport operations also raise the risk of runway incursions. Other factors that may contribute to this safety problem include: when aircraft of different types and capabilities move in close proximity; weather changes that affect visibility and conceal normal visual cue; unclear signs and surface markings; pilots who are unfamiliar with an airport and complex and varied airport geometry.

The FAA’s Airport Technology R&D program is therefore focusing on solutions that will help accommodate traffic growth whilst maintaining a safe operational environment; part of this solution is improving taxiway and obstruction lighting.

Reducing runway incursions

Eliminating runway incursions is a FAA priority. A report released last summer shows incursions have dropped 20 per cent during the past four years. Administrator Marion Blakey credits this success to FAA personnel, the pilot awareness programs and new technology. But that is not enough. The agency’s strategic ‘Flight Plan’ still identifies reducing runway incursions as a critical safety objective.

“The visual guidance R&D program accepts the challenge,” says Donald Gallagher, Visual Guidance Program Manager. “Our work is helping to reach the FAA’s runway incursion reduction goals. Because accidents happen, especially at night, current research centres on why such accidents occur and how to prevent them.”

Last November, researchers spent six nights determining which existing lights make an aircraft more conspicuous to air traffic controllers and pilots, both on the ground and on approach. They recreated conditions blamed for a runway incursion to determine if certain lights, or combinations of lights, work better to alert all concerned about the presence of an aircraft on a runway. The specialists took measurements and recorded reactions from professional pilots in two airplanes. In addition, they took the air traffic controller’s perspective from the tower at Atlantic City International Airport, New Jersey.

Researchers evaluated landing lights, navigation lights, taxi lights, strobe lights, logo lights and rotating beacons. The tests used standard aircraft lights either alone, or in various combinations. Some configurations were flashing, others burned steadily. Subjects judged the effectiveness of the configurations and whether they deemed them adequate to avoid an obstacle on the runway.

Currently researchers are analysing the results from the different light configurations. The final report on aircraft conspicuousness which is expected soon should result in fewer accidents.

General aviation airport lighting

Last year, general aviation pilots used almost 19,000 airports. Many of the smaller general aviation airports have minimal, if any, lighted guidance for pilots taxiing from runways to parking areas. While Advisor Circulars exist for visual aids at airports, a need exists to establish visual guidance aids to airports that do not operate in less than Visual Meteorological Conditions (VMC) with no air carrier service and which only accept aircraft with less than a 10-seat capacity.

The operational characteristics of current visual guidance aids take into consideration the operations at a large segment of general aviation airports. However there are many airports that do not have the operating conditions that the current equipment is certified for. Additionally, others are far removed from metropolitan areas. Some, in Alaska for example, lack road access and have very limited power generation capabilities. Because these airports cannot economically provide the standard lighting systems recommended in the advisory circulars and do not qualify for the Airport Improvement Program, they could benefit from aids that while not providing any ‘visibility credits’, would provide guidance and enhance safety.

The FAA plans to develop a handbook on low cost airport visual guidance infrastructure for these small general aviation airports. Developing the handbook requires two activities: researching remote site requirements and using new technologies that provide low cost, low maintenance and minimal power requirements; and looking at current required lighting to determine if the operational requirements can be reduced for airports operating under the above mentioned conditions. If approved, the lighting infrastructure would also have to be easily applied with minimal maintenance and include airfield visual aids, approach visual aids and power requirements.

As part of these efforts to improve general aviation safety, FAA researchers are now testing solar-powered taxiway lights at Cross Keys Airport in Gloucester County, New Jersey. The solar-powered lights could increase safety at remote sites that lack access to electricity, as well as those airports with limited resources to pay for power. This innovative program could eventually benefit thousands of small general aviation airports across the country. The taxiway lights being tested are the same that guide the pilots of U.S. fighter jets and cargo planes deployed in the Middle East.

In early December 2004, FAA visual guidance specialists began installing 90 taxiway edge lights at Cross Keys (edge lights along the main runway will not be included). Cross Keys Airport, 14 miles southeast of Philadelphia, is representative of a typical general aviation airport that lacks taxiway edge lights. The blue light-emitting diode lights will remain on from dusk to dawn. During the next nine months, researchers will check the test lights for visibility, durability and effectiveness. If approved, the lights could benefit the 452,000 private, student and commercial pilots who use America’s general aviation airports.

Runway hold line enhancements

FAA Advisory Circular AC 150/5340-30, Design and Installation Details for Airport Visual Aids, provides airports with guidance for lighting exit taxiways with colour-coded alternating yellow and green fixtures to warn pilots and vehicle drivers that they are within the runway environment or within the ILS/MLS Critical Area. These coded lights are installed from the runway centerline on the curve to the limit of the runway environment or ILS/MLS Critical Area, facing only towards the runway side of the hold position marking.

Researchers, upon suggestions from industry, examined the feasibility of altering the existing concept of using alternating yellow and green taxiway centerline lights, which warn pilots exiting a runway, to using the same colour coding in the reverse direction as a warning of approach to the runway environment from an intersecting taxiway. A lighting configuration such as this could act as an enhancement to the hold position area, helping to reduce runway incursions. It could also be applied to any airport with existing taxiway centerline fixtures and would have a minimum cost since it would entail only the replacement of a limited number of coloured filters in existing fixtures.

To study this theory, researchers temporarily constructed a curved taxiway entrance lighting configuration, using standard FAA approved taxiway lighting fixtures, at the FAA’s William J. Hughes Technical Centre for evaluation. The simulated taxiway lighting configuration included the following characteristics:

• A lead-in segment of solid green coloured centerline lights for a distance of 200 feet prior to the hold line location (the beginning of the runway environment).
• A continuing segment of alternating yellow and green taxiway lights along the straight and curved section of the taxiway/runway entrance to the point of tangency with the runway centerline.
• All spacing and alignment was in accordance with the appropriate FAA Advisory Circular.
• All fixtures were standard FAA approved L-852 taxiway lights, with standard lamps and filters.

Those helping to test the configuration had the opportunity to view the coded lighting configuration under the existing weather and ambient light conditions after having received a thorough briefing as to the purpose and configuration of the presentation. After viewing the configuration, while standing several hundred yards away, individual subjects were driven in ground vehicles, at typical aircraft taxi speeds, through the display. The vehicle was stopped at the simulated hold position, as though waiting for a clearance and then driven along the curved, colour-coded taxiway lights.

From the evaluation, researchers learned that the concept of illuminating the runway environment area with alternating yellow and green centerline fixtures proved to be a cost-efficient, easy to deploy tool that will have a positive impact on reducing runway incursions at those airports that have existing taxiway centerline lights. A Technical Note will be published covering all of the aspects of this evaluation.

Aviation-friendly energy sources

The U.S. Department of Energy reports that as of March 2004 wind power plants are operating in 32 states. Government experts hope wind will provide six per cent of the nation’s electricity by the year 2020. But, windmills pose threats to airplanes and standards must be established before the campaign to switch to alternative energy progresses further.

FAA regulations require aircraft warning lights on all towers taller than 200 feet, but the turbines on most wind energy farms stand between 300 to 400 feet high. Landowners are concerned that illuminating every windmill in a farm could add annoying light pollution to remote areas.

FAA officials recently reviewed the lighting configuration at Blue Canyon Wind Farm in south central Oklahoma. The facility consists of 43 turbines topped with lights, placed at each end of a row on towers a half-mile apart, for a total of only 17 lights. Researchers determined that this configuration should be sufficient to indicate the farm to pilots and still not create light pollution for surrounding communities.

Engineers have now visited 11 sites. As a result of their research, they plan to recommend a wind turbine farm lighting configuration that will enhance aviation safety while satisfying the concerns of neighbours. They hope that the new recommendations will make wind farms less visible at night to surrounding areas and, therefore, easier to site.

According to Jim Patterson, the FAA’s project lead: “We suggest using red or white synchronised flashing strobe lights, at most 0.5 miles apart, around the perimeter of the wind farm. We hope to identify the entire wind farm as one large obstruction, not a series of small obstructions.”

The windmill lighting project could help realise the dream of alternative energy sources for America, as well as assist in lighting the way for the rest of the world. European nations are among those currently monitoring the FAA’s efforts on the wind farm project. The final report, expected later this year, will likely result in an Advisory Circular determining the future of wind farm lighting in the United States.

Paul Jones

Paul Jones is presently the Manager of the Airport Safety Technology Section in the Airport Technology R&D Branch, located at the FAA’s William Hughes Technical Center, Atlantic City International Airport, NJ. In his present position, Mr. Jones has responsibility for development, modification and evaluation of Airport Visual Guidance Systems, Wildlife Hazard Reduction, Airport Rescue and Firefighting and Runway Surface Technology for the enhancement of safety on airfields.

Mr. Jones is a graduate of the New Jersey Institute of Technology with a Bachelor of Science in Mechanical Engineering. He is a pilot with multi-engine and instrument ratings.