The symbol used on TCAS to indicate proximate traffic is which shape?

• A. Diamond
• B. Circle
• C. Square
• D. Triangle

Answer: (A)

In TCAS displays, the system uses simple shapes to show how close other aircraft are and how urgent a response may be. Proximate traffic is indicated by a diamond shape. This shape is chosen because it stands out clearly and quickly communicates that the other aircraft is nearby enough to require attention, without implying an immediate action like an alert or maneuver. When traffic reaches a higher threat level, TCAS can issue a resolution advisory, and the display will convey that with additional cues, but the proximate target stays identified by the diamond shape to emphasize its closeness and the need to monitor it.