Radar Identification - Primary indicates what?

• A. Receive a transponder reply
• B. See a target on primary radar
• C. Confirm with ATC radio contact
• D. Use GPS triangulation

Answer: (B)

Primary radar works by sending out pulses and detecting the echoes from objects. This means you can see a target on the primary radar display even if the aircraft isn’t equipped to or isn’t replying with a transponder. So “primary indicates” that you have detected a target on primary radar—the radar is showing the presence of an object, giving you range and bearing, but not the aircraft’s identity or altitude.

The other options don’t fit because a transponder reply is from secondary radar, not primary; confirming identity by ATC radio isn’t what the primary indication represents (it’s a separate identification method); and GPS triangulation isn’t how radar identifies targets in ATC.