Which of the following components is required for an Instrument Landing System (ILS) in the US?

An Instrument Landing System (ILS) is a crucial component used to assist pilots in landing aircraft, particularly in low visibility conditions. The system provides precise lateral and vertical guidance to the aircraft as it approaches the runway.

The glideslope is essential because it provides vertical guidance to help pilots maintain the correct descent angle during an approach. This ensures that the aircraft descends at a proper rate, aligning with the runway's threshold.

The localizer serves as the horizontal guidance portion of the ILS. It helps pilots align the aircraft with the centerline of the runway as they approach for landing. The localizer transmits a signal that helps determine whether the aircraft is to the left or right of the runway centerline, allowing for precise navigation.

Additionally, the outer marker is an important component that provides a visual reference point at a specific distance from the runway. It helps pilots know their position during the approach and can trigger alerts for decision-making on whether to continue the approach or go around.

Together, these three components—glideslope, localizer, and outer marker—work cohesively to create a complete ILS system. Therefore, the inclusion of all three components as critical parts of an ILS helps ensure safe and efficient landings in various weather