What is the role of the localizer (LOC) and glide slope (GS) in an ILS approach?

• A. LOC provides horizontal guidance along the runway centerline; GS provides vertical guidance for descent path.
• B. LOC provides vertical guidance; GS provides horizontal guidance only.
• C. LOC provides distance measurement; GS provides altitude reading.
• D. LOC is used for weather data; GS provides wind information.

Answer: (A)

An ILS approach uses two guidance signals to steer you precisely to the runway: horizontal guidance from the localizer and vertical guidance from the glide slope. The localizer keeps you centered on the extended runway centerline, giving left-right deviation information so you can fly a straight path toward the runway. The glide slope provides vertical guidance, showing whether you’re above or below the desired descent path and helping you maintain a steady descent angle to the threshold. Used together, they give you both lateral and vertical guidance for a precise, stabilized approach. The localizer alone would give lateral guidance without a defined vertical path, and the glide slope alone would offer vertical guidance without lateral alignment.