Plain English Meaning

The radio frequency a pilot tunes in to receive the side-to-side guidance signal that lines the aircraft up with a particular runway during an instrument approach.

Full Definition

The specific VHF radio frequency, between 108.10 and 111.95 MHz on odd-tenths channels, on which a runway's localizer transmits its lateral guidance signal for an ILS or LOC approach. Each instrument runway end has its own published localizer frequency that the pilot tunes into the navigation radio to receive course guidance to that runway centerline.

Context Anchor

Seen when setting up or briefing an instrument approach, especially to where each runway may have its own localizer frequency.