From the cockpit at night, a runway is not a strip of tarmac. It is a pattern of coloured lights. Each colour and position tells the pilot something: where the runway starts, where it ends, how much runway is left and whether the approach is too high or too low. This guide explains the main runway lighting systems that pilots, air traffic controllers and airport operations staff work with every day.
Why runways need lights
At night, in rain, haze or fog, pilots cannot rely on seeing the runway surface. Aerodrome lighting follows ICAO Annex 14 standards, so a pilot trained in Chennai reads the same pattern in Dubai or Singapore. The lights do three jobs: guide the aircraft onto the extended centreline, show the correct descent path, and mark the runway's limits during landing and take-off.
The main runway lights
1. Runway edge lights
White lights run along both edges of the runway. On instrument runways the last 600 m (or the last third of the runway, whichever is less) show yellow, warning the pilot that the end of the runway is close.
2. Threshold and runway end lights
A row of green lights marks the threshold, where the usable runway for landing begins. Seen from the other direction, the runway end lights show red: there is no more runway beyond this line.
3. Runway centreline lights
Centreline lights are set into the runway surface. They are white for most of the length, then alternate red and white from 900 m before the end and become all red for the last 300 m. A pilot rolling out in poor visibility can judge the remaining distance without seeing the end of the runway.
4. Touchdown zone lights
Rows of white light bars (barrettes) on either side of the centreline in the first part of the runway mark where the aircraft should touch down. They are used on runways for low-visibility (Category II and III) approaches.
5. Approach lighting system
Before the runway even begins, a pattern of lights extends outward into the approach area, often with sequenced flashing lights that seem to "run" toward the threshold. It lets a pilot coming out of cloud on an instrument approach line up with the centreline quickly.
6. PAPI: the glide path in lights
The Precision Approach Path Indicator (PAPI) is a row of four lights beside the touchdown point. Each unit shows white or red depending on the angle you see it from:
- Two white, two red: on the correct glide path (usually 3°).
- Three or four white: too high.
- Three or four red: too low. Pilots remember it as "red over red, you're dead".
Watch: runway lights in 60 seconds
What about taxiways?
Taxiways use different colours so they are never confused with a runway: blue edge lights and green centreline lights. Red stop bars at runway holding points mark where an aircraft must wait for clearance. They are one of the most important tools against runway incursions.
Who works with runway lighting?
Pilots use it on every night landing. Air traffic controllers set its brightness and switch stop bars. Airport operations and electrical maintenance teams inspect it every day and report outages, because a failed light can change which approaches are allowed. Learning these systems is part of the airport operations and aviation management curriculum, and a common topic in aviation interviews.
Quick revision
- Green = threshold, red = runway end, yellow edge lights = caution zone.
- Centreline: white, then red/white for the last 900 m, then red for the last 300 m.
- PAPI: two white + two red = on slope.
- Taxiways: blue edges, green centreline, red stop bars.
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