A Guide to Commercial Aircraft Lights
If you’ve been to an airport at night, you’ve probably noticed the array of vivid, sparkling lights as aircraft glide down the tarmac. The beaming lights on the airframe are an assortment of fixtures that each serve a specific purpose to aircraft and air traffic control. A few light assemblies that are universal to every commercial aircraft include anti-collision lights, taxi lights, and landing lights.
Anti-collision light fixtures (ACLs) give aircraft, and aircraft controllers, the ability to identify another aircraft. There is a red beacon light on top and bottom of the aircraft fuselage, as well as two white strobe lights— one on each wing tip. These lights are turned off when the engine is shut off due to their intensity. In order to be visible at night, ACL lights can be seen from up to 20 miles away and 40,000 ft. from the ground, which means they can be blinding, literally.
Another version of ACLs are colorful position lights; they are the red and green lights on aircraft wing tips. The red light is always located on the left wing, and the green light is always located on the right wing. There is also a white rear-facing light fixture on the back of each wing. This arrangement allows other aircraft to determine whether an airplane is traveling towards them or away from them. Indicator lights are kept on until the aircraft completes its full flight cycle.
Taxi lights serve a similar purpose as the headlights on an automobile do. They are installed on the nose gear strut, as well as each wing. As an aircraft prepares for landing or takeoff, the taxi lights illuminate the tarmac and allow for easier visibility as they navigate to their gate or runway. The lights cover several feet of ground around the aircraft. When preparing to land, most pilots keep taxi lights off until the tower gives them clearance. This helps eliminate confusion about which aircraft have been cleared to land at any given time. Taxi lights are typically only turned on by the pilot when the aircraft is below 18,000 ft.
If you’ve glanced out a passenger window as the aircraft prepares its final descent, you may have seen landing lights pulsing on the wing. Landing lights are mounted underneath an aircraft fuselage or on the wings of an aircraft. Despite their name, they are also used during take-off. The “blinking” alternates, or pulses, from the left of the aircraft to the right of the aircraft in order to increase visibility as it’s descending. These lights are switched to a static state when an aircraft is around 200 ft. from the ground and can fully illuminate the ground below an aircraft from this distance. Landing lights are extremely bright, alike to the intensity of a spotlight. Landing lights utilize 600-watt bulbs— to put this into perspective, they are over 10x as bright as automotive headlights, and can be seen from miles away.
And there you have it— the practical reasons for a majority of the lights on commercial aircraft. They’re useful, but they’re pretty cool looking too.
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