What is the role of Marker Beacons in an ILS?

Marker beacons play a critical role in the Instrument Landing System (ILS) by delivering precise distance information to pilots as they approach a runway. Specifically, marker beacons are used to indicate certain points along the final approach path, such as the outer marker, middle marker, and sometimes the inner marker. These beacons emit signals that inform pilots of their distance from the runway threshold, contributing to the safe and accurate navigation of aircraft during landing operations.

By providing this precise distance information, marker beacons assist pilots in maintaining the appropriate descent profile and timing for their approach, ensuring that they are properly aligned for landing. This element of the ILS is essential for successful aircraft operations, particularly in low visibility conditions where visual references are limited.