What is the width of a localizer at the runway threshold?

• A. 600 feet
• B. 700 feet
• C. 800 feet
• D. 900 feet

Answer: (B)

The localizer defines the lateral guidance corridor for an ILS approach, and its ground footprint at the runway threshold is a fixed, published width. That footprint is about 700 feet wide, which sets the usable area on the ground where the localizer signals guide you toward the runway centerline as you reach the threshold. This standard width ensures the lateral guidance is precise enough for a stable approach across typical runway configurations. The other numbers aren’t used because they don’t match the established localizer footprint used in instrument approach design.