What is the purpose of Control Tower Visibility Aids in ATC operations?

• A. To maintain a visibility checkpoint chart or list of visibility markers posted in the tower for determining tower visibility.
• B. To record aircraft flight times.
• C. To manage runway lighting schedules.
• D. To track weather radar data.

Answer: (A)

Control Tower Visibility Aids provide standardized references for judging how far and what the tower can see from its position. A visibility checkpoint chart or list of visibility markers posted in the tower defines the features and markers used to assess tower visibility, giving the controller a fixed frame of reference. By comparing actual visibility to these markers, the controller can consistently determine whether visibility is sufficient for operations, decide what clearances to issue, and maintain uniform decisions across shifts. This is not about recording flight times, managing runway lighting, or tracking weather radar; it’s about having objective, repeatable references to determine what the tower can observe.