Plain English Meaning

It's the signal that tells the aircraft whether it's lined up left or right of the runway as it comes in to land. It doesn't tell the pilot how high to be -- only how to stay on track side-to-side toward the runway.

Full Definition

The lateral (left/right) guidance signal provided to an aircraft on final approach, indicating its alignment with the runway centerline. In Microwave Landing System (MLS) operations, approach azimuth guidance is transmitted from a ground station located beyond the stop end of the runway and defines a wide coverage sector through which the aircraft can intercept and track the final approach course.

Context Anchor

Seen in discussions, especially when describing that guide an aircraft toward the runway for .