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ACRP
REPORT 148

AIRPORT
COOPERATIVE
RESEARCH
PROGRAM

Sponsored by
the Federal
Aviation
AdministrationLED Airfield Lighting System

Operation and Maintenance

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ACRP OVERSIGHT COMMITTEE*

CHAIR

Kitty Freidheim
Freidheim Consulting

VICE CHAIR

Kelly Johnson
Northwest Arkansas Regional Airport Authority

MEMBERS

Deborah Ale Flint
Oakland International Airport
Thella F. Bowens
San Diego County Regional Airport Authority
Benito DeLeon
Federal Aviation Administration
Richard de Neufville
Massachusetts Institute of Technology
Kevin C. Dolliole
Unison Consulting
Steve Grossman
Jacksonville Aviation Authority
F. Paul Martinez
Dallas/Fort Worth International Airport
Bob Montgomery
Southwest Airlines
Eric Potts
Freese and Nichols, Inc.
Richard Tucker
Huntsville International Airport
Paul J. Wiedefeld
Baltimore/Washington International Airport

EX OFFICIO MEMBERS

Sabrina Johnson
U.S. Environmental Protection Agency
Christopher Oswald
Airports Council International—North America
Laura McKee
Airlines for America
Melissa Sabatine
American Association of Airport Executives
T.J. Schulz
Airport Consultants Council
Neil J. Pedersen
Transportation Research Board
Gregory Principato
National Association of State Aviation Officials

SECRETARY

Christopher W. Jenks
Transportation Research Board

TRANSPORTATION RESEARCH BOARD 2015 EXECUTIVE COMMITTEE*

OFFICERS
Chair: Daniel Sperling, Professor of Civil Engineering and Environmental Science and Policy;

Director, Institute of Transportation Studies, University of California, Davis
ViCe Chair: James M. Crites, Executive Vice President of Operations, Dallas/Fort Worth International Airport, TX
exeCutiVe DireCtor: Neil J. Pedersen, Transportation Research Board

MEMBERS
Victoria A. Arroyo, Executive Director, Georgetown Climate Center; Assistant Dean, Centers and

Institutes; and Professor and Director, Environmental Law Program, Georgetown University Law Center,
Washington, DC

Scott E. Bennett, Director, Arkansas State Highway and Transportation Department, Little Rock
Deborah H. Butler, Executive Vice President, Planning, and CIO (retired), Norfolk Southern Corporation,

Norfolk, VA
Jennifer Cohan, Secretary, Delaware DOT, Dover
Malcolm Dougherty, Director, California Department of Transportation, Sacramento
A. Stewart Fotheringham, Professor, School of Geographical Sciences and Urban Planning, University of

Arizona, Tempe
John S. Halikowski, Director, Arizona DOT, Phoenix
Michael W. Hancock, Secretary, Kentucky Transportation Cabinet, Frankfort
Susan Hanson, Distinguished University Professor Emerita, School of Geography, Clark University,

Worcester, MA
Steve Heminger, Executive Director, Metropolitan Transportation Commission, Oakland, CA
Chris T. Hendrickson, Professor, Carnegie Mellon University, Pittsburgh, PA
Jeffrey D. Holt, Managing Director, Bank of Montreal Capital Markets, and Chairman, Utah Transportation

Commission, Huntsville
Roger Huff, Manager, Ford Global Customs, Material Export Operations, and Logistics Standardization,

Ford Motor Company, Farmington Hills, MI
Geraldine Knatz, Professor, Sol Price School of Public Policy, Viterbi School of Engineering, University of

Southern California, Los Angeles
Ysela Llort, Consultant, Miami, FL
Donald A. Osterberg, Senior Vice President, Safety and Security (retired), Schneider National, Inc., Freedom, WI
James Redeker, Commissioner, Connecticut DOT, Newington
Mark Rosenberg, President and CEO, The Task Force for Global Health, Inc., Decatur, GA
Sandra Rosenbloom, Professor, University of Texas, Austin
Henry G. (Gerry) Schwartz, Jr., Chairman (retired), Jacobs/Sverdrup Civil, Inc., St. Louis, MO
Kumares C. Sinha, Olson Distinguished Professor of Civil Engineering, Purdue University, West Lafayette, IN
Kirk T. Steudle, Director, Michigan DOT, Lansing
Gary C. Thomas, President and Executive Director, Dallas Area Rapid Transit, Dallas, TX
Paul Trombino III, Director, Iowa DOT, Ames

EX OFFICIO MEMBERS
Thomas P. Bostick (Lieutenant General, U.S. Army), Chief of Engineers and Commanding General,

U.S. Army Corps of Engineers, Washington, DC
James C. Card (Vice Admiral, U.S. Coast Guard, retired), Maritime Consultant, The Woodlands, TX,

and Chair, TRB Marine Board
Alison Jane Conway, Assistant Professor, Department of Civil Engineering, City College of New York, NY,

and Chair, TRB Young Members Council
T. F. Scott Darling III, Acting Administrator and Chief Counsel, Federal Motor Carrier Safety Administration,

U.S. DOT
Marie Therese Dominguez, Administrator, Pipeline and Hazardous Materials Safety Administration, U.S. DOT
Sarah Feinberg, Acting Administrator, Federal Railroad Administration, U.S. DOT
David J. Friedman, Acting Administrator, National Highway Traffic Safety Administration, U.S. DOT
LeRoy Gishi, Chief, Division of Transportation, Bureau of Indian Affairs, U.S. Department of the Interior,

Washington, DC
John T. Gray II, Senior Vice President, Policy and Economics, Association of American Railroads,

Washington, DC
Michael P. Huerta, Administrator, Federal Aviation Administration, U.S. DOT
Paul N. Jaenichen, Sr., Administrator, Maritime Administration, U.S. DOT
Therese W. McMillan, Acting Administrator, Federal Transit Administration, U.S. DOT
Michael P. Melaniphy, President and CEO, American Public Transportation Association, Washington, DC
Gregory G. Nadeau, Administrator, Federal Highway Administration, U.S. DOT
Peter M. Rogoff, Under Secretary for Transportation Policy, Office of the Secretary, U.S. DOT
Mark R. Rosekind, Administrator, National Highway Traffic Safety Administration, U.S. DOT
Craig A. Rutland, U.S. Air Force Pavement Engineer, Air Force Civil Engineer Center, Tyndall

Air Force Base, FL
Barry R. Wallerstein, Executive Officer, South Coast Air Quality Management District, Diamond Bar, CA
Gregory D. Winfree, Assistant Secretary for Research and Technology, Office of the Secretary, U.S. DOT
Frederick G. (Bud) Wright, Executive Director, American Association of State Highway and Transportation

Officials, Washington, DC
Paul F. Zukunft (Admiral, U.S. Coast Guard), Commandant, U.S. Coast Guard, U.S. Department

of Homeland Security

* Membership as of November 2015.* Membership as of July 2015.

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Maintenance Considerations 35

manufacturers have worked closely with the airports to resolve issues and then took the neces­
sary steps to prevent the failure from occurring in future fixtures.

Vibration

Vibration is typically associated with the airfield operating environment due to moving air­
craft and the forces they generate. As use of LED fixtures began to gain momentum in airfield
applications, vibration became a concern given the various electronic components incorporated
in the fixtures. The FAA requires airfield lighting manufacturers to subject in­pavement fixtures
to vibration and shock tests. AC 150/5345-46, Specification for Runway and Taxiway Light Fixtures,
states that fixtures must be subjected to a sinusoidal vibration along three mutually perpendicu­
lar axes. The first part of the test vibrates the fixture over a frequency range of 20 to 500 Hz with
a maximum acceleration of 10Gs. The second part of the test vibrates the same fixture from
500 to 2,000 Hz, with a maximum acceleration of 15 times the force of gravity. Each part of the
test must have a duration of 10 minutes. At the conclusion of the test, the fixture is thoroughly
inspected for mechanical damage, loosened components, loss of continuity, or movement of
the diode which is cause for rejection of the fixture. For shock testing, which applies to runway
in­pavement lighting, the fixture is mounted to a 1­in.­thick steel plate or a 4­in.­thick concrete
base. Steel or concrete must not be less than 3 square feet in size. Once assembly is complete,
the fixture is set to the highest brightness level for 2 hours prior to the start of the test. With the
fixtures still at highest brightness, a 5­pound steel ball is dropped on the center of the light from
a height of 6 feet. This step is repeated 10 times at 5­minute intervals between drops. At the
conclusion of the test, the fixture internals are inspected for failures or displaced components.
Any evidence of damage or LED failure is a cause for rejection.

Vibration due to aircraft impacts is believed to be one of the causes for premature failure of
LED airfield fixtures. Pinpointing the effects of vibration is difficult because clear data does not
exist on what happens to fixture internals as an aircraft runs over it. Some of the airport personnel
who completed the survey mentioned that vibration was a cause of LED failure on the airfield
shortly after installation. In cases where lights failed due to vibration, the fixtures were typically
still under warranty and issues were repaired by the manufacturer. Fixtures failing due to vibration
were most commonly taxiway centerline lights at runway high­speed exits. Taxiway centerline
lights are not required to comply with the rigorous impact testing that runway centerline lights
are subjected to.

The following survey response from a medium­hub airport in a cold­climate environment
demonstrates how vibration has affected LED fixtures:

When we first installed L­852 LEDs on a high speed taxiway, off a runway, we had a high rate of failures.
We had not experienced the same issue on slower taxiways. Ultimately, we attributed this to the high number
of 747s and MD11s . . . causing high rates of vibration in the fixtures. Basically, the leads were breaking off
the light engines. [The lighting manufacturer] pursued the problem and repairs, under warranty. After a
couple of rebuilds and product improvement, the LEDs are holding up.

A large­hub airport stated the following:

We have had a lot of runway fixtures go out in the first couple months of operations. Specifically centerlines
and some touchdown fixtures.

Earlier generation fixtures were more susceptible to vibration damage. Resistors, capacitors,
and other circuit board components would break away from the circuit board, causing the fixture
to immediately fail. However, product improvement, for example, by potting the electronics
and reducing the number of “moving parts,” has resolved many of the problems. Some light
manufacturers established test beds to determine whether LED fixtures were more susceptible
to vibration in comparison with their incandescent equivalents. For example, one manufacturer

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36 LED Airfield Lighting System Operation and Maintenance

installed their fixtures at a Naval Air Facility to subject them to a more severe environment
than on a typical airfield. After many landings and tail­hook strikes, no fixture failures due to
vibration were reported. (http://www.adb­air.com/media/10333/ADB­Tech­Corner­Answers­
High­Intensity­Airfield­Lighting.pdf) The results showed that newer generation LED fixtures are
more stable and durable in high vibration areas. By incorporating more solid­state and passive
components, fixtures are now more resilient to vibration. In comparison, incandescent fixtures
still incorporate a wire filament. When exposed to vibration, these filaments are susceptible
to failure.

If an airfield is experiencing repeated failures in certain areas, specifically if these areas are
runway centerlines, high­speed taxiways or touchdown zones, it may be due to vibration. A good
practice is to discuss this topic with the airfield lighting vendor to better understand how equip­
ment will perform in high­vibration areas. The case studies revealed that the areas mentioned
above were typical areas for premature failure due to vibration and shock.

There are industry concerns regarding loosening in­pavement fixture hold­down bolts, regard­
less of the fixture type. Although FOD damage is the primary concern, loose bolts can amplify
vibration damage. After being exposed to the various forces of aircraft movement, the bolts
holding in­pavement fixtures down have been known to loosen if not fastened properly or have
sheared off when fastened too tight. Whenever a fixture is not properly fastened, vibration to
the fixture increases, which inherently increases the probability of damaged fixture electronics,
disconnection of wiring, or loosening of components within the fixture.

AC 150/5340-26 requires airports to check the torquing of in­pavement light fixture bolts
bi­monthly, at a minimum. If an area experiences repeated failures, that area should be checked
more frequently. Vibration issues were not as evident in incandescent lights because the fixtures
were visited more often for re­lamping. LEDs do not require re­lamping and, therefore, are not
visited as often. A good practice, especially for airfields with high LED usage, is to have a work
plan and special crews assigned only to bolt torquing. Some of the airports included in the case
studies stated that they have special crews that go out, usually at night, to check bolt torquing.
These airports had different parts of the airfield testing scheduled at different times of the year to
accommodate the work load. Although this may seem like an additional maintenance requirement
for LEDs, it is not. The same amount of maintenance, if not more, is required when re­lamping an
incandescent. Furthermore, AC 150/5340-26 requires the same torquing checks for incandescent
fixtures. More research is being conducted on bolt torquing issues, but a solution is yet to be
determined. Maintenance records should be maintained by the airport to ensure that bolt main­
tenance schedules are followed.

Key Takeaways

• Fixtures in runway centerlines, high-speed taxiway centerlines,
or touchdown zones may experience greater failure rates due to
vibration from more consistent high-impact aircraft movement.

• Discuss vibration with the manufacturer to better understand
technological advancements and how issues can be alleviated.

• Maintain proper bolt torquing on light fixtures by creating
a testing schedule and stocking the correct tools.

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Abbreviations and acronyms used without definitions in TRB publications:

A4A Airlines for America
AAAE American Association of Airport Executives
AASHO American Association of State Highway Officials
AASHTO American Association of State Highway and Transportation Officials
ACI–NA Airports Council International–North America
ACRP Airport Cooperative Research Program
ADA Americans with Disabilities Act
APTA American Public Transportation Association
ASCE American Society of Civil Engineers
ASME American Society of Mechanical Engineers
ASTM American Society for Testing and Materials
ATA American Trucking Associations
CTAA Community Transportation Association of America
CTBSSP Commercial Truck and Bus Safety Synthesis Program
DHS Department of Homeland Security
DOE Department of Energy
EPA Environmental Protection Agency
FAA Federal Aviation Administration
FHWA Federal Highway Administration
FMCSA Federal Motor Carrier Safety Administration
FRA Federal Railroad Administration
FTA Federal Transit Administration
HMCRP Hazardous Materials Cooperative Research Program
IEEE Institute of Electrical and Electronics Engineers
ISTEA Intermodal Surface Transportation Efficiency Act of 1991
ITE Institute of Transportation Engineers
MAP-21 Moving Ahead for Progress in the 21st Century Act (2012)
NASA National Aeronautics and Space Administration
NASAO National Association of State Aviation Officials
NCFRP National Cooperative Freight Research Program
NCHRP National Cooperative Highway Research Program
NHTSA National Highway Traffic Safety Administration
NTSB National Transportation Safety Board
PHMSA Pipeline and Hazardous Materials Safety Administration
RITA Research and Innovative Technology Administration
SAE Society of Automotive Engineers
SAFETEA-LU Safe, Accountable, Flexible, Efficient Transportation Equity Act:
A Legacy for Users (2005)
TCRP Transit Cooperative Research Program
TDC Transit Development Corporation
TEA-21 Transportation Equity Act for the 21st Century (1998)
TRB Transportation Research Board
TSA Transportation Security Administration
U.S.DOT United States Department of Transportation

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