Concentric rings on instrument approach procedure charts are dashed-line circles outside the reference circle that show en route and feeder facilities. Which option best completes this statement?

• A. Local weather facilities
• B. Airport traffic zones
• C. En route and feeder facilities
• D. Terminal area navigation fixes

Answer: (C)

These concentric dashed rings indicate the network of en route and feeder facilities that connect the en route structure to the instrument approach. En route facilities are the navigation aids and airways you use while flying between airports, and feeder facilities are the routes that bring you from those en route paths into the terminal area and toward the approach. Casting these rings outside the reference circle helps you visualize where you can transition from en route navigation to the approach procedure, showing how the approach is fed from the broader navigation system. The other options don’t fit because weather facilities aren’t depicted this way on approach charts, airport traffic zones aren’t shown as this ringed pattern, and terminal area navigation fixes are specific charted points rather than these surrounding facility networks.