What is the primary purpose of the localizer during an instrument approach?

What is the primary purpose of the localizer during an instrument approach?

• A. Align the aircraft with the runway centerline
• B. Provide vertical guidance
• C. Provide range distance
• D. Indicate wind information

Answer: (A)

The localizer provides horizontal guidance to keep the aircraft aligned with the runway extended centerline. It transmits a signal that the cockpit instruments interpret as left-right deviation from the runway course; when the course deviation indicator (CDI) centers, you’re on the runway centerline, guiding you to the approach end. This is what lets you fly a precise lateral path toward the runway. It does not supply vertical guidance—that comes from the glide slope—nor does it give range distance (that’s from DME or other range equipment), and it doesn’t provide wind information.

The localizer provides horizontal guidance to keep the aircraft aligned with the runway extended centerline. It transmits a signal that the cockpit instruments interpret as left-right deviation from the runway course; when the course deviation indicator (CDI) centers, you’re on the runway centerline, guiding you to the approach end. This is what lets you fly a precise lateral path toward the runway. It does not supply vertical guidance—that comes from the glide slope—nor does it give range distance (that’s from DME or other range equipment), and it doesn’t provide wind information.