Home » Energy Efficent LED PAPI

INTRODUCTION

There is a National Initiative to reduce the dependence of the United States on conventional fossil fuels.  Critical to the success of this initiative is the development of more energy efficient means for carrying out the important tasks of society.  One aspect of direct interest is the reduction of electrical power consumed by the nation’s airports, and airport lighting is an important subsection or this task. 

The FAA has pioneered the development of LED based lighting solutions for all aspects of airport lighting.  Stellar Photonics and its partners have developed a successful design for the LED PAPI (Precision Approach Path Indicator) that can produce the required 30,000 cd of white, and 15,000 cd of red light for the high and low sectors of the Light Housing Assembly (LHA). 

This design has demonstrated that it can achieve up to 90% reduction in input electricity, while reducing maintenance requirements by a factor of 10.  Nationwide adoption of this LED PAPI design will result in substantial savings in electricity and significant reduction in ongoing operating expenses. 

 
ENERGY EFFICIENT 

When compared to a conventional PAPI LHA, the saving in electricity provided by Stellar’s design is significant.  A typical PAPI system requires 2400 watts to operate at full power, and 30 percent of that to operate at its’ night time setting.  If one assumes that the system operates on the average for 12 hours a day at its’ day setting, and 8 hours per day at its night setting the total power consumption per day for a conventional PAPI will be approx 35000 watt-hours per day (or  35.000 kilowatt hours/day).

RELIABLE

In addition to the power savings, the STELLAR LED PAPI system will be 10 times more reliable than currently deployed PAPI’s.   Current halogen lights last approximately 2000 hours while LEDs last greater than 20,000 hours. When combined with the reduced electrical requirements, the result is a much lower ongoing operations cost to maintain the airport infrastructure.

CLEARER SIGNALS

Another advantage for the LED PAPI is that the PAPI’s signals will be clearer to the pilots.  This is due to the limited spectral nature of LED light.  In conventional PAPIs, both the red and white signals use relatively broad spectral light.  When propagating through the atmosphere the blue portions of the spectrum are more easily scattered by the intervening air.  This leads to a shift in apparent color with distance towards the red and makes the signal less easy to distinguish, particularly in hazy or foggy conditions.  LED light (even the white) is much narrower in spectral width leading to colors that appear sharper, and with less color distortion.

EASE OF MAINTENANCE

The STELLAR design also features a cassette based mounting system for the LED’s.  The LED’s are mounted on an easily accessible cassette which can be unscrewed and replaced in less than 5 minutes.  Removal and replacement of a cassette will not change the alignment, or other critical aspects of the LHA.