LED green threshold lamp
Approach Light Systems (ALS) provide the basic means to transition from instrument flight to visual flight for landing. The FAA Lighting Systems Office is in the process of researching the use of Light Emitting Diodes (LEDs) in an approach lighting system application. Under a Small Business Innovative Research (SBIR) contract, LED threshold lamps have been developed that produce similar light intensities and colors of incandescent lamps used in a Medium Intensity Approach Lighting System with Runway Alignment Indicator Lights (MALSR). These lamps have been evaluated at the William J. Hughes Technical Center and found to provide the same visual cues to pilots as the incandescent threshold lamps with green filters. Following this evaluation, five LED Threshold Lamps underwent environmental testing at an independent lab. The lamps successfully completed temperature, vibration, icing, photometric, chromaticity, and electrical characteristics tests. Upon completion of these tests, two sets of green lamps (18 per site) were installed on operational runways at the Grand Forks International Airport and Phoenix�s Sky Harbor Airport for a one-year operational evaluation. Data on power consumption and pilot surveys were collected on a bi-monthly basis. The preliminary results appear encouraging.

Additional work under the SBIR includes the development of LED steady burning white LED lamps, which will replicate the existing PAR-38 lamps and screw into a PAR 38 lamp holder. Other work includes development of an LED In-Pavement lamp in an L850E base. The FAA took delivery of one green and five white lamps for evaluation at the WJH Technical Center. Upon completion of this evaluation, environmental tests will be conducted at an independent lab on the lamps. Another funded effort is to develop a feasibility study to determine if the LED technology can replicate a MALSR flasher.

Cost Benefit Data: The FAA conducted a cost benefit analysis (CBA) on the replacement of PAR-56 incandescent lamps with LED lamps for all MALSR threshold light applications were conducted. The study concluded that there was a 2.5 benefit in replacement lamps and the sensitivity analysis confirmed that the decision was sound. Lamp life and lamp costs were the two most influential factors. Estimated savings were $24.7M and the costs of the change would be returned in only 2 years.

FAA Technical Lead:
Ndubuisi Nnorom - (202) 493-4661

Current Status: The FAA continues LED testing and development and is working on developing a MALSR and PAPI LED contract.