Runway End Identifier Lights – Purpose and Characteristics

What are Runway End Identifier Lights (REAL)?

Runway End Identifier Lights (REAL) play a crucial role in airport lighting, providing pilots with clear, immediate identification of the runway’s threshold.

The system consists of two synchronized, high-intensity flashing lights, one on each side of the runway entrance. Their distinct strobe effect cuts through visual clutter from other airport or city lights, making the runway unmistakable.

Rails enhance a pilot’s situational awareness, helping to prevent runway confusion, reduce in-cockpit workload, and safeguard against landing short of the runway. They become critical at airports with multiple runways or when visibility is poor.

Characteristics of REAL Lights

• Configuration**: A pair of synchronized, unidirectional white strobe lights, one on each side of the runway threshold.

• Flash Rate**: Calibrated to flash between 60 and 120 times per minute.

• Aiming**: Each light is angled 10 to 15 degrees outward from the runway to face the approach path.

• Intensity**: Equipped with three adjustable settings for day, night, and varying weather conditions.

• Visibility**: Visible from up to 3 miles during the day and 20 miles at night.

Centerline Lights

To ensure precise alignment, many instrument runways feature Runway Centerline Lights.

Like edge lights, centerline lights use color-coding to signal the remaining runway distance.

Runway Edge Lights

While centerline lights provide longitudinal guidance, Runway Edge Lights define the runway’s lateral boundaries.

Edge lights also use color to convey crucial distance information.

Runway Light Colors and Their Meanings

Light colors on an airfield function as essential communication for pilots. Each color conveys specific, standardized information essential for safe operations.

• Green**: Marks the runway threshold, indicating the start of the usable surface.

• White**: Outlines the runway edges and marks the centerline for most of its length.

• Yellow**: Serves as a caution signal, replacing white edge lights on the last 2,000 feet of the runway.

• Red**: Signifies the end of the runway, used for the final 1,000 feet of centerline lights and to mark the runway end.

• Blue**: Outlines taxiways, clearly distinguishing them from runways.

Regulations Governing Runway Lighting

Aviation regulations from aviation authorities—such as the Federal Aviation Administration (FAA) in the U.S. and the International Civil Aviation Organization (ICAO) globally—ensure airport safety and standardization. These bodies define every aspect of runway lighting to ensure pilots interpret them uniformly worldwide.

For instance, FAA and ICAO standards precisely define the characteristics of Rails—from their placement and synchronization to their precise flash frequency (60–120 times per minute). This standardization ensures clear identification of the runway’s approach end.

These regulations create a predictable environment that enhances pilot situational awareness and prevents accidents, particularly in low visibility. This standardized lighting system forms the foundation of safe airport operations.

Conclusion

Rails represent an essential component of aviation safety.