Which marker is used as the standard decision maker?

Which marker is used as the standard decision maker?

• A. Outer marker
• B. Inner marker
• C. Middle marker
• D. Approach lighting

Answer: (C)

Marker beacons on an ILS provide fixed reference points along the final approach. The middle marker is the standard decision maker because it marks the conventional decision height for most ILS approaches, giving you the point at which you should have the required visual references to continue the landing. If you don’t have the runway environment in sight by that point, you should execute a missed approach. The inner marker is used only for the most precise approaches (CAT II/III) at lower decision heights, and the outer marker appears earlier along the approach. Approach lighting is a separate visual aid, not the official decision point.

Marker beacons on an ILS provide fixed reference points along the final approach. The middle marker is the standard decision maker because it marks the conventional decision height for most ILS approaches, giving you the point at which you should have the required visual references to continue the landing. If you don’t have the runway environment in sight by that point, you should execute a missed approach. The inner marker is used only for the most precise approaches (CAT II/III) at lower decision heights, and the outer marker appears earlier along the approach. Approach lighting is a separate visual aid, not the official decision point.