What is the primary use of localizers at airports?

The primary use of localizers at airports is to provide horizontal guidance to aircraft. Localizers are an essential part of an Instrument Landing System (ILS), which helps pilots accurately align their aircraft with the centerline of the runway during the approach phase of landing. The localizer transmits a radio signal that allows the aircraft's navigation system to determine its position relative to the runway. This capability is crucial for safe landings, especially in conditions with reduced visibility.

By providing precise lateral positioning information, localizers help pilots ensure that they are on the correct flight path, which enhances safety during landing operations. This function is indispensable in busy airport environments where multiple aircraft are approaching for landing.