Definition
A form of air traffic surveillance in which an aircraft is detected and tracked by ground-based sensors without any active signal or response from equipment on the aircraft itself. Primary surveillance radar, which bounces a radio pulse off the aircraft's skin and reads the return, is the most common example.
Plain English
The controller can see the aircraft on radar even though nothing on the aircraft is sending information back. The radar finds it on its own.
Context Anchor
Seen in air traffic control and surveillance discussions, especially when comparing primary radar with systems that depend on aircraft equipment replies.
Derivation
‘Non cooperative’ means the aircraft is not cooperating with the surveillance system — not in a hostile sense, but in the technical sense that it is not actively helping the system find or identify it. ‘Surveillance’ comes from the French ‘surveiller’, meaning ‘to watch over’.
Why Pilots Care
Provides detection capability for aircraft with failed or absent transponders and supplies independent backup when cooperative systems are unavailable.
Intuition Check
Non cooperative does not mean the pilot is being unhelpful or refusing instructions. It means the surveillance system does not depend on the aircraft’s equipment sending information back.
Example Sentence 1
Primary radar provides non cooperative surveillance, allowing controllers to see aircraft even when their transponders have failed.
Example Sentence 2
In remote areas with only non-cooperative surveillance, the controller still receives skin-paint returns from the aircraft.