Wednesday, August 1, 2001
In-Pavement Light Emitting Diode (LED) Light Strip Evaluation
DOT/FAA/AR-01/39 Author: Donald W. Gallagher
In-Pavement Light Emitting Diode (LED) Light Strip Evaluation
Painted markings on runways, taxiways, and apron surfaces are often obliterated, particularly at night, when covered by even a thin layer of water or other forms of precipitation. An effective method for delineating critical areas and/or locations on the airport surface is essential.
Recently developed usage of light emitting diode (LED) light sources have been the encapsulation of a string of LED lights to provide a continuous light strip. These strips can be readily imbedded within, and virtually flush with, the pavement surface. Properly installed, they should be completely compatible with snowplow operations and, being sealed or encapsulated, would require only a minimum of maintenance. LED devices require comparatively low levels of power and have demonstrated minimal failure rates in service.
A test LED-strip configuration was installed in the form of a parking location T at the number one parking spot on the apron area of the Federal Aviation Administration William J. Hughes Technical Center. It was comprised of five 3-meter (10-foot) sections, or strips, forming the crossbar of the T and an additional nine sections forming the tail of the T.
Experienced pilots and lighting personnel participated in a subjective evaluation consisting of a series of questions to evaluate the parking location configuration. All participants felt that they could see and identify the LED-strip lighting in time to easily execute the approach to the parking spot. All participants felt the LED lighting presentation was sufficiently clear and it identified the location for what it was, a parking position. All but one of the participants rated this proposed addition/modification to painted surface markings as well worth while, one rated it marginal help.
In conclusion, operationally, the LED light strips do enhance airport paint markings. This technology can be acquired from a much farther distance than paint markings. Another major advantage of this technology is its visibility when covered with standing water, whereas paint markings become obliterated. On the issue of snow covering, however, this technology becomes obliterated the same as paint markings.
DOT/FAA/AR-01/39
Author: Donald W. Gallagher