ILSapproach

An Instrument Landing System, often abbreviated as ILS, is a ground-based electronic navigation system that provides precision guidance to an aircraft approaching a runway. It enables pilots to descend through weather conditions that would otherwise be too poor to allow for a visual landing. The ILS is comprised of several components, the most critical being the localizer and the glideslope.

The localizer transmits a radio signal that provides lateral guidance, indicating whether the aircraft is to the left or right of the runway centerline. This signal is typically received by an antenna array located beyond the far end of the runway. Pilots monitor the localizer on their instrument panel, which shows a deviation indicator that moves left or right based on their position relative to the centerline.

The glideslope transmits a radio signal that provides vertical guidance, indicating whether the aircraft is above, below, or at the correct angle of descent towards the runway. This signal is broadcast from an antenna located on the side of the runway, approximately one-third of the way down its length. Similar to the localizer, a glideslope indicator on the instrument panel shows the aircraft's vertical position relative to the desired descent path.

In addition to the localizer and glideslope, an ILS system may include marker beacons. These are low-power transmitters located at specific distances from the runway threshold, providing audible and visual cues to the pilot as they pass over them, indicating their position along the approach path. Together, these components allow for a safe and precise approach and landing, even in low visibility conditions.