Localizer
What is localizer?
The localizer (LOC) is the part of an Instrument Landing System (ILS) that provides lateral (left/right) guidance to keep you aligned with the runway centerline. Its ground antenna array sits at the departure end of the runway and radiates a field pattern that defines a course straight down the extended centerline. Think of it as the "steering" of an ILS approach—it tells you whether you're left or right of centerline, but says nothing about your altitude.
Also known as: LOC, localizer course
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