Definition
An imaginary line projected outward from each end of a runway along the same heading as the runway centerline, used as a reference for aligning the aircraft on final approach and after takeoff.
Plain English
If you drew a straight line out from the end of the runway, continuing in the same direction the runway points, that line is the runway centerline extension. Pilots use it as an invisible track to fly along when landing or departing.
Context Anchor
Used when flying the traffic pattern, especially when turning toward final approach or tracking straight out after takeoff.
Derivation
Centerline means the line through the middle of something. Extension comes from a word meaning to stretch out. Together, the phrase means the runway’s middle line continued outward beyond the actual runway.
Why Pilots Care
It gives pilots a clear, consistent reference point for entering and leaving the traffic pattern so everyone flies predictable paths and maintains safe separation.
Intuition Check
Do not think of the runway centerline extension as a painted line you can always see on the ground. In this context, it is usually an imaginary reference line continuing straight out from the runway centerline.
Example Sentence 1
The pilot rolled out of the base-to-final turn directly on the runway centerline extension and continued the approach.
Example Sentence 2
After takeoff the aircraft continued straight ahead past the runway centerline extension before turning crosswind.