If you have ever visited a major airport at night, it is highly likely you have spotted various kinds of lighting as you soar into the sky, which can range from a steady red or blue hue to a flashing white. Without these lights, it would not be possible for aircraft to operate once the day turns into night.
One of the most important lights at an airport are, of course, the runway lights, which are available in multiple forms. If you’ve ever wondered their purpose, here is everything you need to know about runway lighting.
Runway Edge Lighting Systems
The next time you are at an airport at night, look out for steady white lights along the edges of a runway. These are runway edge lights, which are white lights that will turn to a yellow hue when a plane approaches the final 2,000 feet or half the runway length. Once an aircraft reaches the end of a runway, the lights will turn to red. There are a wide array of runway lights available in different intensities, such as high intensity (HIRL), medium intensity (MIRL), or low intensity (LIRL).
A Runway Centreline Lighting System
You will find runway centreline lighting systems (RCLS) installed on a precision runway. The white lights are often spread across 50-ft intervals located on the runway’s centreline, hence the name. The lights will alternate between white and red when there are 3,000 feet remaining, and then will turn to a fixed red at the last 1,000 feet. This is to indicate the remaining runway length to the pilot.
Touchdown Zone Lights
You can probably gather the purpose of touchdown zone lights (TDZL) by the name. It is essential lighting provided in airports during low visibility so that a pilot can identify a touchdown area.
They are the fixed white lights located in the two rows flanking the centreline. The lights will start at 100 feet and will extend to either the runway’s midpoint or 3,000 feet below the threshold, whichever one is less.
Runway Guard Lights
Runway guard lights, which are known as wig-wags to pilots, were introduced in many airports in 1995 to increase safety. While you might never have noticed the flashing amber lights, they will warn a pilot when they are set to taxi onto a runway.
A unit is mounted onto each side of a taxiway where an aircraft will be required to stop. A pilot can only taxi past the guard lights once they have received clearance from an air traffic controller.
Land and Hold Short Lights
During Land and Hold Short Operations (LAHSO), you might notice flashing white lights across the runway’s hold short line. You also should look out for other forms of lighting, such as the Take-off Hold Light Array (THL), Runway Intersection Lights (RILs), and the Final Approach Runway Occupancy Lights (FAROS), which will each inform both ground vehicle operators and pilots when it is safe for them to either cross or enter a runway.