What is the total degree spread of the localizer coverage range at 18 nautical miles?

The total degree spread of the localizer coverage range at 18 nautical miles is 10 degrees. This is because localizers are designed to provide guidance to pilots approaching a runway, and their signal coverage is specifically engineered to ensure that the aircraft can reliably receive and interpret the localizer signals for accurate navigation.

At a distance of 18 nautical miles from the runway, the localizer's coverage is typically defined to provide adequate precision in terms of lateral guidance within that limited angular spread. The 10-degree spread allows for some margin of error to accommodate aircraft deviations while still ensuring that pilots can capture and maintain the correct flight path toward the runway. This configuration is established to meet safety and regulatory standards, signifying that the localizer remains effective at this distance.

Understanding the coverage range is crucial for pilots as it informs them of how much deviation from the centerline can be tolerated while still remaining on course during an approach.