What does it mean when runway centerline lights change from white to alternating red and white?

The transition of runway centerline lights from white to alternating red and white indicates that there are 3,000 feet of runway remaining. This color change serves as an important visual cue for pilots, notifying them that they are approaching the end of the usable runway.

When pilots see this signal, it helps them assess their landing or takeoff situation and make crucial decisions regarding their speed and distance from the threshold. This system enhances situational awareness, particularly on busy runways, during various weather conditions, and at night, facilitating safer flight operations.

This specific distance marked by the alternating lights is part of the standardized visual aids that enhance both the safety and efficiency of aircraft operations on the ground.