Runway lighting is used at airports that allow night landings. Seen from the air, runway lights form an outline of the runway. A particular runway may have some or all of the following:
- Runway end identifier lights (REIL) – unidirectional (facing approach direction) or omnidirectional pair of synchronized flashing lights installed at the runway threshold, one on each side.
- Runway end lights – a pair of four lights on each side of the runway on precision instrument runways, these lights extend along the full width of the runway. These lights show green when viewed by approaching aircraft and red when seen from the runway.
- Runway edge lights – white elevated lights that run the length of the runway on either side. On precision instrument runways, the edge-lighting becomes amber in the last 2,000 ft (610 m) of the runway, or last third of the runway, whichever is less. Taxiways are differentiated by being bordered by blue lights, or by having green centre lights, depending on the width of the taxiway, and the complexity of the taxi pattern.
- Runway centerline lighting system (RCLS) – lights embedded into the surface of the runway at 50 ft (15 m) intervals along the runway centerline on some precision instrument runways. White except the last 900 m (3,000 ft): alternate white and red for next 600 m (1,969 ft) and red for last 300 m (984 ft).
- Touchdown zone lights (TDZL – rows of white light bars (with three in each row) at 30 or 60 m (98 or 197 ft) intervals on either side of the centerline for 900 m (3,000 ft).
- Taxiway centerline lead-off lights – installed along lead-off markings, alternate green and yellow lights embedded into the runway pavement. It starts with green light at about the runway centerline to the position of first centerline light beyond the Hold-Short markings on the taxiway.
- Taxiway centerline lead-on lights – installed the same way as taxiway centerline lead-off Lights, but directing airplane traffic in the opposite direction.
- Land and hold short lights – a row of white pulsating lights installed across the runway to indicate hold short position on some runways that are facilitating land and hold short operations (LAHSO).
- Approach lighting system (ALS) – a lighting system installed on the approach end of an airport runway and consists of a series of lightbars, strobe lights, or a combination of the two that extends outward from the runway end.
According to Transport Canada’s regulations, the runway-edge lighting must be visible for at least 2 mi (3 km). Additionally, a new system of advisory lighting, runway status lights, is currently being tested in the United States.
The edge lights must be arranged such that:
- the minimum distance between lines is 75 ft (23 m), and maximum is 200 ft (61 m);
- the maximum distance between lights within each line is 200 ft (61 m);
- the minimum length of parallel lines is 1,400 ft (427 m);
- the minimum number of lights in the line is 8.