Definition
An instrument approach in which an air traffic controller uses radar to provide the pilot with azimuth (heading) guidance to the runway. The controller issues headings to fly so the aircraft tracks the final approach course, and advises the pilot when to begin descent to the published minimum descent altitude. The pilot is responsible for descent and lateral tracking using that guidance; the controller does not provide vertical guidance to the runway.
Plain English
A radar-assisted approach where a controller watches the airplane on a radar screen and tells the pilot what heading to fly to line up with the runway, and tells the pilot when to start coming down. The pilot still flies the airplane and handles the descent; the controller is just giving directions.
Context Anchor
Seen in instrument flying when radar service is available and the pilot needs controller-provided guidance for an approach to an airport.
Derivation
Surveillance comes from the French surveiller, meaning to watch over. Here it points to the controller watching the aircraft on radar and guiding it down. It is not surveillance in the sense of spying — just continuous radar observation by ATC.
Why Pilots Care
Allows a safe landing when visibility is too low for visual flight but the aircraft lacks other instrument approach equipment or the airport has no published procedures.
Grounding Statement
Picture the pilot flying in low visibility while the controller watches the radar screen and gives simple turn instructions to line the aircraft up with the runway.
Intuition Check
Surveillance does not just mean that someone is watching the flight. Here it means a specific radar approach where the controller uses that watching to give active guidance to the pilot.
Example Sentence 1
With the GPS unreliable, the pilot requested a surveillance approach and followed the controller's headings down to minimums.
Example Sentence 2
ATC provided vectors for the surveillance approach to runway 27.