Definition
The painted line of white dashes running lengthwise down the middle of a runway, marking its longitudinal axis and providing a visual reference for alignment during takeoff, landing, and rollout.
Plain English
The white dashed line painted down the middle of the runway. Pilots use it to keep the airplane straight and centered when taking off or landing.
Context Anchor
Seen during taxi onto the runway, the takeoff roll, the landing flare, and the landing roll.
Why Pilots Care
Proper alignment with the runway center line maintains directional control and prevents runway excursions or side-loads on landing gear.
Intuition Check
Do not treat the runway center line as just a rough suggestion near the middle. In normal takeoff and landing, it is the main visual reference for keeping the airplane aligned with the runway.
Example Sentence 1
After lining up for takeoff, the pilot held the nosewheel on the runway center line and smoothly advanced the throttle.
Example Sentence 2
On final approach the pilot made small corrections to stay on the runway center line until touchdown.