Memphis International Airport
experienced a dip in passenger traffic when Delta Airlines pulled their hub status, but those unused runways may shine a little brighter thanks to technology from Oak Ridge National Laboratory
(ORNL) being tested by FedEx Corporation
According to the Department of Transportation and Federal Aviation Administration, LED bulbs are significantly less visible than traditional incandescent light bulbs when viewed through enhanced flight vision systems (EFVS). Despite this, random installations of LEDs are now occurring at airports and on obstacles across the country to comply with the Energy Independence and Security Act of 2007. The act mandates phasing out incandescent light bulb use for energy conservation purposes. Some northern runways have tested LEDs, but pilot feedback was negative, citing that the LEDs were both too bright, blinding pilots, and too efficient – they weren’t hot enough to show up in the infrared cameras used to assist pilots in poor weather. EFVS ability to image LEDs is diminished due to light wave length and reduced heat signature when compared to traditional incandescent lights.
To solve these problems, Skip Monk, Founder of Spectrum FML, Inc. asked James Klett, a Senior Research Staff Member in ORNL’s Materials Science & Technology Division, and his team to help them overcome some of the technical challenges involved in replacing incandescent bulbs used for airport lighting. “They’re so efficient and cool they are invisible to the EFVS in adverse weather conditions,” said Klett.
Klett has devoted his career to working with forms of carbon, including inventing a thermally conductive and lightweight material called graphite foam. Graphite foam emits energy across the spectrum in a very uniform fashion. When viewed under a hyper-spectral imager, the output of the foam is over 90 percent efficient (compared to 10 percent for incandescent bulbs) and emits radiation sensed by a very wide range of aircraft, helicopter, unmanned aerial vehicle and infrared cameras.
The team tested LED concepts that will give pilots an improved view of the runway in normal conditions without being too bright and that will enhance the pilot’s capabilities to track the runway in inclement weather. They incorporated an induction heated graphite foam source that generates a specific infrared spectrum that can be picked up by an airplane’s EFVS. The rough prototype was tested for a few months earlier this year at Memphis International Airport by FedEx.
“The purpose of that test is to ensure our EFVS cameras installed on aircraft with heads up display and EFVS to help operate our aircraft in adverse weather conditions will properly detect and image the infrared light radiated. The other purpose of the ongoing testing is to ensure the proposed replacement lights are also compatible with current airport runway lights,” said Kerns.
The prototype tested in Memphis was then sent to Washington, D.C. to be evaluated by those at the FAA. After their input or approval, plans are to continue testing and evaluating to optimize the lights. Work has been fast, but there is not yet a timetable for a commercial product or expanded implementation. FedEx and ORNL have follow up plans to test the next phase or a second prototype light that will emit both visible and infrared light and fit inside the standard flood light housing. But the researchers expect the final outcome to be lights that will far outlast current runway lights and will be capable of withstanding weather and temperature extremes.
If all goes well, this work promises safety, savings, and cooler summer nights, at least on the runway at Memphis International.