Do not allow vehicles or aircraft operations in or over the ILS critical area when an arriving aircraft is inside the MM, 1/2 miles final, and the weather observation indicates a ceiling of less than _________ or RVR less than __________.

• A. 200 ft; 2,000 ft
• B. 300 ft; 3,000 ft
• C. 100 ft; 1,500 ft
• D. 400 ft; 2,500 ft

Answer: (A)

The situation tests how weather and visibility affect protection of the ILS critical area when an arriving aircraft is very close to landing. The ILS critical area must be kept clear to prevent signal interference and ensure the arriving airplane can complete the approach safely.

The correct thresholds are a ceiling of 200 ft or an RVR of 2,000 ft. When either of these is exceeded (i.e., the ceiling is below 200 ft or the RVR is below 2,000 ft) and an arriving aircraft is inside the MM, half-mile final, vehicles and aircraft should not operate in or over the ILS critical area. These values represent the standard protective limits for maintaining safe instrument approach operations.

The other options use different values that do not match this protective standard, so they don’t provide the same level of safety for the critical area during a near-landing instrument approach.