The minimum components of an ILS are Localizer, Glidepath, and which additional system?

The minimum components of an ILS are Localizer, Glidepath, and which additional system?

• A. RVR
• B. Approach lighting system
• C. GPS
• D. DME

Answer: (B)

An instrument landing system relies on two active guidance signals to direct the aircraft: the localizer for horizontal guidance and the glide path for vertical guidance. The third component that completes the set is the approach lighting system, which provides the pilot with vital visual cues during the approach. It helps identify the runway environment, judge distance, and transition from instrument flight to visual alignment with the runway, especially in low visibility. The other options aren’t part of the ILS structure: RVR is a visibility measurement, not a component of the landing guidance; GPS is satellite navigation used for en route or approach guidance but not part of the ILS; DME is distance measuring equipment for navigation, not part of the ILS installation.

An instrument landing system relies on two active guidance signals to direct the aircraft: the localizer for horizontal guidance and the glide path for vertical guidance. The third component that completes the set is the approach lighting system, which provides the pilot with vital visual cues during the approach. It helps identify the runway environment, judge distance, and transition from instrument flight to visual alignment with the runway, especially in low visibility.

The other options aren’t part of the ILS structure: RVR is a visibility measurement, not a component of the landing guidance; GPS is satellite navigation used for en route or approach guidance but not part of the ILS; DME is distance measuring equipment for navigation, not part of the ILS installation.