airport lighting system

An airport lighting system , or ALS, is a lighting system installed on the approach end of an airport runway and consisting of a series of lightbars, strobe lights, or a combination of the two that extends outward from the runway end. ALS usually serves a runway that has an instrument approach procedure (IAP) associated with it and allows the pilot to visually identify the runway environment and align the aircraft with the runway upon arriving at a prescribed point on an approach.

Modern approach lighting systems are highly complex in their design and significantly enhance the safety of aircraft operations, particularly in conditions of reduced visibility.

Airports are hard to see at night, especially runways (where take-offs and landings occur) and taxiways (paved paths that lead between runways and the passenger or cargo terminal ramps). Using colored lights to outline the areas on which aircraft move makes them easier to see and follow at night.

Runways have the most complex lighting, and there are many different ways to light the runway. White lights alone the sides of the runway are typical, with some arrangement of red and/or yellow lights to help mark the ends. Complex light arrangements may be set up just off each end of the runway to help pilots spot the start of the runway at landing and help them to line up precisely with the middle of the runway as they come in toland. Other lights at the runway ends help pilots to check that they are at the correct height above the runway as they descend for landing. Sometimes airport lighting system is used, such as the “rabbit,” a line of bright white lights that flashes in sequence at the end of a runway, pointing pilots in the right direction for landing.

Outside of runways, taxiways are usually outlined in blue lights. At airports where the weather is often misty or foggy, green lights may be installed on the centerlines of the taxiways in addition to the blue lights at the edges, so that the pilots can find their way between the runways and terminals even when it’s hard to see very far.

There are other lights that some airports use, such as flashing “traffic lights” near runways, or red lights in the pavement right in front of a runway (to remind pilots that they are about to enter a runway), and so on.

Lights are not used in exactly the same way at every airport in the world, but they are used in ways consistent enough that pilots usually don’t have any trouble finding their way around on the ground and lining up with the runway during landing.

Blue are taxiway lights, green mark the end of a runway or a centerline embedded light on a taxiway, red can be the far end of a runway or part of the instrument landing system… There are lots of different color lights used in different situations. There are a few books, specifically the AIM (Airmen’s Information Manual) that could give details for you.

http://www.faa.gov/airports_airtraffic/air_traffic/publications/ATpubs/AIM/chap2toc.htm

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