Besides the localizer and glide slope, which element is commonly used with ILS during an instrument approach?

Besides the localizer and glide slope, which element is commonly used with ILS during an instrument approach?

• A. DME
• B. Marker Beacons
• C. VOR
• D. TACAN

Answer: (B)

Marker beacons provide fixed-distance cues along the ILS approach path to supplement the localizer and glide slope. They come in outer, middle, and back course markers, each giving distinct signals (audible codes and lights) to confirm you’re on the correct path and to mark key points as you approach the runway. The outer marker is encountered farther out where you would typically be preparing to intercept the glideslope; the middle marker signals closer in and helps verify your descent path near the decision point. Although modern procedures can substitute distance information with DME or GPS, marker beacons are the traditional element commonly associated with ILS, making them the best answer.

Marker beacons provide fixed-distance cues along the ILS approach path to supplement the localizer and glide slope. They come in outer, middle, and back course markers, each giving distinct signals (audible codes and lights) to confirm you’re on the correct path and to mark key points as you approach the runway. The outer marker is encountered farther out where you would typically be preparing to intercept the glideslope; the middle marker signals closer in and helps verify your descent path near the decision point. Although modern procedures can substitute distance information with DME or GPS, marker beacons are the traditional element commonly associated with ILS, making them the best answer.