Definition
A row of flush-mounted, high-intensity lights installed along the centerline of a runway, spaced at uniform intervals, used to provide guidance during takeoff and landing in low-visibility conditions. The lights are white for most of the runway length, alternate red and white over the final 3,000 feet, and become solid red over the last 1,000 feet to indicate the runway end is approaching.
Plain English
A line of lights set into the surface of the runway, right down the middle, to help the pilot stay centered when taking off or landing in poor visibility. The colors change near the end of the runway to warn the pilot that the runway is running out.
Context Anchor
Seen on some paved runways during night operations, low-visibility takeoffs, landings, and rollout after touchdown.
Why Pilots Care
They give precise visual alignment guidance that reduces the chance of drifting off the runway edges, especially when visibility is poor.
Intuition Check
Do not confuse runway centerline lights with runway edge lights. Centerline lights mark the middle of the runway; edge lights mark the sides.
Example Sentence 1
On the foggy approach, the runway centerline lights gave the captain a clear visual reference to keep the airplane tracking straight after touchdown.
Example Sentence 2
During the low-visibility takeoff, the runway centerline lights provided the only reliable reference until the aircraft lifted off.