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).