What is the purpose of the Instrument Landing System (ILS)?

The Instrument Landing System (ILS) is specifically designed to provide precision guidance to aircraft during the approach and landing phases, especially in conditions of low visibility such as fog, rain, or snow. It consists of two primary components: the localizer and the glideslope. The localizer helps pilots to align the aircraft with the centerline of the runway, while the glideslope provides vertical guidance to ensure the proper descent angle is maintained as the aircraft approaches the runway. This precision guidance is critical for safely landing an aircraft when visual references may be limited or unavailable.

Other options address different aspects of aviation that do not pertain specifically to the primary function of the ILS. Pre-flight planning involves assessing flight routes and conditions, general navigation is focused on the broader journey of the flight rather than landing specifically, and air traffic management is concerned with the coordination of multiple aircraft in an airport environment rather than the precision landing guidance provided by the ILS.