Which term designates areas where disturbances to the ILS localizer and glideslope may occur due to surface vehicles operating near the equipment?

• A. Runway exclusion zones
• B. Localizer protection zones
• C. Taxiway shoulders
• D. Critical areas near the antennas

Answer: (D)

Interference with ILS signals happens when surface vehicles or equipment operate close to the localizer and glideslope antennas, potentially distorting or blocking the guidance signals. To keep the system reliable during approach and landing, predefined zones around the antennas restrict surface traffic. These are called critical areas near the antennas. The other terms aren’t the standard way to describe the protected zones around ILS equipment: runway exclusion zones cover broader runway safety areas, taxiway shoulders relate to pavement structure on taxiways, and localizer protection zones isn’t the conventional terminology used for this purpose.