Plain English Meaning

An invisible line in the sky, broadcast by a ground radio station, that the pilot tracks by keeping a needle centered on the cockpit display. A VOR sends out many of these lines in all directions, and the pilot picks one to fly. A localizer sends out just one, lined up with the runway, used during landing approaches.

Full Definition

A specific ground track defined by a VOR (VHF Omnidirectional Range) radial or a localizer signal, which the pilot follows by keeping the course deviation indicator centered. A VOR is any selected radial radiating from a , while a course is the narrow, fixed - transmitted by a localizer aligned with the .