The Instrument Landing System provides which type of guidance?

• A. Lateral guidance only
• B. Vertical guidance only
• C. Both lateral and vertical guidance
• D. Altitude readouts only

Answer: (C)

An Instrument Landing System gives you both horizontal and vertical guidance on approach. The localizer provides lateral guidance, guiding you left or right to keep the aircraft centered on the runway's centerline. The glide slope provides vertical guidance, telling you whether you’re above or below the proper descent path and helping you descend along a precise glide angle toward the runway.

Together, these two signals let you align your aircraft with the runway and maintain the correct descent path, which is why it’s considered a precision approach. As you fly, you center the localizer needle to stay on the runway centerline and center the glide slope needle to stay on the proper glide path. When the glide slope is captured and you’re on both paths, you follow them down to the runway.

Altitude readouts come from the aircraft’s instruments (like the altimeter) and other systems, not from the ILS itself, so describing it as “altitude readouts only” doesn’t fit what the ILS provides.