On an ILS, if the Localizer is lost, what is the status of the approach?

On an ILS, if the Localizer is lost, what is the status of the approach?

• A. The approach is unusable without the localizer
• B. The glide slope will compensate automatically
• C. You can continue on a localizer-only approach
• D. Switch to a VOR approach

Answer: (A)

An ILS relies on two independent guidance signals: lateral guidance from the localizer and vertical guidance from the glide slope. Both must be available for the approach to be flown as an ILS. If the localizer signal is lost, you lose the runway-centerline guidance, and the glide slope alone cannot provide horizontal guidance. In short, without the localizer, the ILS approach is not usable as published. You would need to switch to a different authorized approach (such as a VOR or RNAV approach) or execute a missed approach and plan an alternate routing.

An ILS relies on two independent guidance signals: lateral guidance from the localizer and vertical guidance from the glide slope. Both must be available for the approach to be flown as an ILS. If the localizer signal is lost, you lose the runway-centerline guidance, and the glide slope alone cannot provide horizontal guidance. In short, without the localizer, the ILS approach is not usable as published. You would need to switch to a different authorized approach (such as a VOR or RNAV approach) or execute a missed approach and plan an alternate routing.