Unveiling the Secrets of Longer-Lasting AGL Airport Lights (+ Bonus Assessment Tool).
Tender specs almost always stipulate that lights must comply with CASA or ICAO standards. And sometimes they stipulate a smooth glass lens, which is a great start.
But, the key to a long-lasting airport can be found in the datasheets and reports from the airport lighting manufacturer.
This is an insider’s explanation into what 3 details to examine, the reasons why, and where to find the information.
There’s also bonus assessment tool with 9 more metrics at the end of this article to help with your decision making.
1. Temperature: Why AGL Light Materials are critical to lifespan
The lifetime of Airport Lights can vary from 60,000 to 350,000 hours. Longer lasting Airport lights are better at moving heat away from the LED. The goal is to carry heat away from the LED, using the light body as the vehicle.
LEDs are temperature sensitive. Poor heat management results in:
Reduction in lifetime hours
Decrease in light output (intensity)
Airport lights contend with scorching days on a remote airstrip plus the LED fixture itself generating heat.
The material of the light body is critical.
Metallic light bodies are conductive, so transfer heat away from the LED. This lengthens the life of the airport light.
Plastic insulates and traps heat, decreasing the life of the LED.
The longest lasting airport lights have an LED board fixed with thermal paste to a metallic fixture. This is ideal for conducting heat away from the LEDs.
If your airport is in a salty environment, make sure the fixture is anodised to protect it from corrosion. Anodising is like GOR-TEX for light fixtures. Marine equipment stays in good condition even in harsh saltwater exposure.
In summary: LEDs degrade faster if the light body fails to transfer heat away. Look for materials with natural conductive properties.
The graph below illustrates the plunge in performance hours when heat is poorly managed.
L70 lifetime of an LED light source as function of junction temperature (Copyright Cree Inc)
What to examine: A light body made from metallic parts and a large surface area for the circuit board to dissipate heat is ideal.
For a white runway edge light, anything within the range of 100-200 candela (aka brightness) is technically, MOS Part 139 compliant for low intensity.
But it’s better to install LEDs running at low intensity on the upper end of the brightness range.
Here’s why: LEDs gradually lose their brightness. And higher currents = faster decline in brightness.
The goal is to optimise the brightness within the rated current of the LED, without causing dazzle to the pilot
For example, a new white runway edge light at 170 candela at 350mA will stay within the compliant range for longer than a new light that only emits 130 candela at 750mA.
Runway lights illuminated at less than 130cd
Runway lights illuminated at more than 170cd
The lens material can also dull the light. When plastic lenses are exposed to UV light, the plastic turns cloudy, smothering the light output. Without regular maintenance and lens replacements, the runway becomes dull and drops out of the 100-200cd range.
In summary, A brighter light from the start, running at a low current with a smooth glass lens means a long lasting AGL Airport light modern LED, with a smooth glass lens, means a longer lasting light – and a better ROI for council.
What to examine?
Airport light LEDs can only be as new as the date of their last NATA test. The date on this document provides a clue about which generation of LEDs are in the light.
The NATA test report or the airport lighting manufacturers datasheet shows the average intensity of the runway edge lights. As long as the LEDs are new generation (and running within the recommended current parameters) above 160cd is ideal for a low intensity runway for a longer lasting compliance. It’s also important to consult with your engineer to consider the environment of the specific airport to avoid dazzling the pilot.
3. LED’s: Newer or Older Generation?
Lifespan, brightness, colour, heat tolerance and efficiency have all gotten better with each generation of LED. AGL Airport lights made with newer LEDs through more light with less energy. Some reasons for this:
Improved chip design means improved brightness while maintaining efficiency
Enhanced phosphor coatings have led to brighter and more vibrant light
Advanced optics boosts the perceived brightness.
Airport lights with newer LEDs will throw more light using less power. And they handle heat and stress better.
Older LEDs throw less light, using more power to do so. They handle heat poorly and don’t last as long.
In summary: It is better to have airport lights with a newer generation of LED because they last longer and perform better than older generations.
What to examine? A lifetime test report is the best way to assess the quality of the LEDs. If its not available, the airport lighting manufacturer can give the NATA test certificates. Check the date on the test certificate. A more recent test date may indicate a newer generation of LEDs. Keep in mind the lights may have been retested with old LEDs.
Bonus Assessment Tool
We made an assessment tool to help you compare and choose the best airport light for your aerodrome. As a bonus, we added 9 more metrics to use in your evaluation.
Download this article and your assessment tool today!
Lee is an Airport Lighting consultant and owner at Aerolight Airports. Lee helps you save money on lights and build a more reliable airport for emergency services and locals. Lee is a mum and enjoys running (not at a gym - its too boring).