Definition
A form of air traffic surveillance in which the aircraft actively contributes to its own detection by transmitting information to ground systems. This is done through onboard equipment such as a transponder or an ADS-B Out unit, which sends identification, altitude, and (for ADS-B) position data to ATC. Examples include secondary surveillance radar, ADS-B, ADS-C, and Wide Area Multilateration.
Plain English
Surveillance where the aircraft helps the ground system see it by sending out its own signals, rather than just being spotted passively.
Context Anchor
Seen in air traffic control, radar services, transponder use, ADS-B discussions, and surveillance system descriptions.
Derivation
Cooperative comes from the Latin cooperari, meaning to work together. The aircraft and ground system are working together to produce the surveillance picture, rather than the ground system doing all the work alone.
Why Pilots Care
Determines whether your aircraft meets modern ATC tracking standards and remains visible during flight in controlled airspace.
Intuition Check
Cooperative does not mean the pilot is helping by talking on the radio. Here it means the aircraft’s equipment is taking part by sending or replying with data.
Example Sentence 1
Because the aircraft was equipped with both a Mode C transponder and ADS-B Out, it was fully visible to ATC through cooperative surveillance.
Example Sentence 2
Controllers rely on cooperative surveillance from equipped aircraft for accurate altitude and position updates during busy traffic periods.