LED Evaluation

Nonincandescent Source Aviation Signal Light Colors

Aviation signal lighting systems are increasingly replacing filtered and unfiltered incandescent lamps with light-emitting diode (LED) sources to create various signal light colors. As LED sources produce spectral distributions that can differ in color appearance from incandescent signal lights, it is important to understand how the characteristics of LEDs influence color identification.

The objective of this research was to provide chromaticity regions for aviation signal lights that maximize the likelihood of correct identification while minimizing the potential for confusion with other colors.

Three color identification studies of aviation signal lights were conducted to produce white, yellow, red, blue, and green colors using filtered and unfiltered incandescent lamps and LEDs. The objectives of these studies were to (1) identify chromaticity regions resulting in a high probability of correctly identifying aviation signal lights as white; (2) compare the color identification performance of color-normal and color-deficient observers in response to incandescent and LED signal lights of each nominal color (white, yellow, red, blue, and green); and (3) identify chromaticity regions resulting in a high probability of correctly identifying aviation signal lights as yellow, red, or blue.

Based on the results of these studies, recommendations for each of the nominal signal colors are provided in the Commission Internationale de l’Éclairage 1931 chromaticity space.

Link to the FAA Technical Note titled "Nonincandescent Source Aviation Signal Light Colors". This is an Adobe Acrobat file (format: PDF, size: 2.2 MB).

In-Pavement Light Emitting Diode (LED) Evaluation

Painted markings on runway, taxiway, and apron surfaces are often obliterated when covered by even a thin layer of water, there is a need to provide a more effective method of marking or delineating critical areas and/or locations on the non-movement and possibly movement areas on an airport. Conventional in-pavement (semi-flush/inset) lights can be used; however, they are expensive and costly to install and maintain.

The commercial lighting industry has recently developed a light strip system that utilizes a series of encapsulated light emitting diodes (LED) to provide a continuous line of closely spaced lights. The string of diode lights can be easily embedded within the pavement surface so as not to hinder snowplowing operations and, being sealed or encapsulated, require only a minimum of maintenance. LED devices are noted for requiring comparatively low level of power for operation and have demonstrated minimal failure rates.

Airport R&D will evaluate the effectiveness of, and determine the performance characteristics of these LED light strips for airport use. Strips will be installed and evaluated at the William J. Hughes Technical Center.

Link to the FAA Technical Note titled  "In-Pavement Light Emitting Diode (LED) Light Strip Evaluation" for non-movement areas on the airport. This is an Adobe Acrobat Version 5.0 file (format: PDF, size: 8.1MB).

Project Lead: Donald W. Gallagher , Airport R&D

Last Update:01/28/13