Each and every light on an airfield has a specific purpose. Runway and taxiway lighting systems are essential for guiding pilots during takeoff, landing, and taxiing, especially during low visibility conditions like night or poor weather. These lights are color-coded to provide clear information about the runway’s layout and status, ensuring safe operations. Understanding the colors of these lights is critical for pilots.
Runway lights
Light type Color Purpose
Runway Edge Lights White/Yellow (near end) To outline the runway edges
Runway Centerline Lights White (Red/White near end, Red at the end) To guide aircraft along the center of the runway
Threshold Lights Green (start) / Red (end) To mark runway start and end
Taxiway Edge Lights Blue To define the taxiway edges
Taxiway Centerline Lights Green Guide aircraft along the center of taxiways
REILs Flashing White To enhances visibility of runway threshold
Runway Edge Lights are white and outline the edges of the runway. On instrument runways, the last 600 meters (or 2000 feet) may be yellow to signal the runway’s end. These lights help pilots maintain proper alignment during takeoff and landing.
Runway Centerline Lights are embedded into the runway and provide guidance along the center. These lights are white, but in the final 900 meters (about 3,000 feet) of the runway, the lights alternate between red and white to signal that the runway is ending. The last 300 meters (about 1,000 feet) are all red.
Threshold Lights mark the beginning and end of the runway for landing aircraft. These lights are green when viewed from the approach direction, indicating the runway’s start. From the opposite direction, the lights are red, signaling the runway’s end.
Runway End Identifier Lights (REILs) are flashing white lights located on either side of the runway threshold. They are designed to make the runway end more visible from a distance.
What are the four red and white lights to the left of the runway?
PAPI (Precision Approach Path Indicator) lights are a set of lights positioned alongside the runway that help pilots maintain the correct glide slope during an approach for landing. They consist of four lights that display either white or red, depending on the aircraft’s angle of approach. When a pilot sees two white lights and two red lights, it indicates that they are on the correct glide path. More white lights mean the aircraft is too high, and more red lights mean the aircraft is too low.
Taxiway lighting
Taxiway lights primarily enhance safety by clearly defining the taxi routes, reducing the risk of runway incursions, and ensuring that aircraft move efficiently on the ground.
Light Type Color Purpose
Taxiway Edge Lights Blue Outline the edges of the taxiway
Taxiway Centerline Lights Green Guide the aircraft along the center of the taxiway
Clearance Bar Lights Amber (Yellow) To indicate holding positions or intersections
Stop Bar Lights Red To prevent aircraft from entering a runway without clearance
Runway Guard Lights Flashing Amber Alert pilots when they are approaching a runway and need to exercise caution
Taxiway Edge Lights are blue and outline the edges of the taxiway. These lights provide clear boundaries to prevent aircraft from veering off the taxiway onto other surfaces. The blue edge lights are particularly important in areas where there are no physical markings or where the visibility is low.
Taxiway Centerline Lights are green and installed along the center of the taxiway. These lights guide the aircraft along the proper path. Centerline lights are especially useful at complex or busy airports where there are multiple taxiways and intersections.
Clearance Bar Lights are installed at holding positions or taxiway intersections. These lights are amber (yellow) and serve as a visual cue to indicate that the pilot must stop and wait for clearance to proceed.
Stop Bar Lights are red and are used at runway crossings or hold points. These lights ensure that aircraft do not inadvertently enter a runway without permission. When the pilot receives clearance to proceed, the stop bar lights turn off, and the green taxiway centerline lights illuminate to indicate that the aircraft can move forward.
Runway Guard Lights are amber and flash to alert pilots that they are approaching a runway. They are positioned on either side of a taxiway that intersects a runway, emphasizing the need for caution.
Next time you’re at an airport at night, why not take a look out the window and test your knowledge!
Cover photo: Andy Fonseca, JetPhotos
![An example full flight summary response from the Flightradar24 API: { "data": [ { "fr24_id": "0987654321", "flight": "SK1415", "callsign": "SAS1415", "operated_as": "SAS", "painted_as": "SAS", "type": "A20N", "reg": "SE-DOY", "orig_icao": "ESSA", "orig_iata": "ARN", "datetime_takeoff": "2023-01-27T05:15:22", "runway_takeoff": "12R", "dest_icao": "EKCH", "dest_iata": "CPH", "dest_icao_actual": "EPWA", "dest_iata_actual": "WAW", "datetime_landed": "2023-01-27T06:15:10", "runway_landed": "27L", "flight_time": 3600, "actual_distance": 1007.74, "circle_distance": 6245, "category": "Passenger", "hex": "4A91F9", "first_seen": "2023-01-27T05:06:22", "last_seen": "2023-01-27T06:18:10", "flight_ended": "true" } ] }](https://www.flightradar24.com/blog/wp-content/uploads/2025/04/Flight-summary-API-cover-300x148.jpg)
