What are the range, altitude, and angular width for Localizer reception?

• A. 18 NM, 4500 ft AGL, and 10 degrees
• B. 10 NM, 4500 ft AGL, and 35 degrees
• C. 18 NM, 3000 ft AGL, and 25 degrees
• D. 18 NM, 6000 ft AGL, and 10 degrees

Answer: (A)

Localizer reception is defined by its service volume, which limits where you can reliably receive horizontal guidance. The usable range extends out to about 18 nautical miles from the antenna, and the signal is dependable only up to about 4500 feet above the airport elevation. In addition, the localizer provides a usable lateral guidance band within roughly 10 degrees on either side of the runway centerline, keeping the course guidance accurate within that narrow angular width. Therefore, the best match is 18 NM, 4500 ft AGL, and about 10 degrees. The other options either suggest too high an altitude or a wider angular band than the localizer can reliably provide.