Definition
A precision or surveillance radar approach in which a controller on the ground watches the aircraft on radar and gives the pilot continuous spoken instructions for heading, and (on a precision approach) glidepath, to guide the aircraft down to the runway. The pilot flies the airplane while the controller talks them down.
Plain English
An approach where a controller watches your airplane on radar and tells you, by radio, exactly which way to turn and when to descend so you line up with the runway. You fly the plane; they do the navigating.
Context Anchor
Seen in instrument procedures, military or special-use airport information, and airport qualification notes where radar approach service may be available or required.
Derivation
The name describes itself: 'ground-controlled' because the guidance comes from a controller on the ground, and 'approach' because it is the final descent toward landing. Worth keeping in mind because it tells you immediately who is doing the directing — not the aircraft's instruments, but a human watching radar.
Why Pilots Care
Allows a safe landing at airports lacking ILS or other onboard precision aids and in weather that would otherwise prevent the flight from continuing.
Intuition Check
Ground-controlled does not mean the controller flies the airplane. The pilot flies the airplane; the controller gives radar-based instructions from the ground.
Example Sentence 1
With the onboard navigation equipment unreliable, the pilot requested a GCA into the military field and followed the controller's headings and descent calls down to the runway.
Example Sentence 2
During the GCA the controller called, "Turn right heading two seven zero, descend to one thousand feet."