Definition
The Air Traffic Control service in which controllers use radar returns to monitor the position of aircraft and issue instructions for separation, navigation, and traffic flow within a defined airspace. It combines two functions: surveillance (watching where aircraft are) and control (issuing clearances and instructions based on what is seen).
Plain English
Controllers watch aircraft on a radar screen and use what they see to give pilots instructions about heading, altitude, and traffic, keeping aircraft safely apart and moving in an orderly flow.
Context Anchor
Used in en route instrument flying when a Center or Approach controller has your aircraft on radar and may give route, altitude, or heading instructions.
Derivation
Radar' is an acronym for Radio Detection And Ranging, developed in the 1930s and 40s. 'Surveillance' comes from the French surveiller, meaning 'to watch over.' Together the phrase describes watching over aircraft using radio-based detection, then controlling them based on that watching.
Why Pilots Care
Maintains safe aircraft separation and enables efficient routing when visual references or onboard navigation alone are insufficient.
Analogy
It is like someone watching several moving cars on a screen and giving directions so they do not get too close to each other.
Intuition Check
Surveillance does not mean the controller is secretly watching you; here it means actively monitoring your aircraft’s position. Control does not mean the controller flies the airplane; it means the controller gives instructions you must follow when cleared or instructed.
Example Sentence 1
Once handed off to Center, the flight was under radar surveillance and control for the remainder of the en route phase.
Example Sentence 2
Radar surveillance and control allowed the controller to vector the aircraft around weather while maintaining separation from other traffic.