Definition
Authorization issued by ATC permitting a pilot to conduct an instrument approach procedure. The clearance typically specifies the type of approach to be flown and constitutes approval to descend and execute the published procedure once the aircraft is on a published segment of the approach.
Plain English
Permission from air traffic control to fly a published instrument approach down to the runway. Once you have it, you are cleared to follow the procedure as charted.
Context Anchor
Heard on the radio during instrument flying when a controller clears an aircraft to begin the final published path toward an airport.
Derivation
“Approach” comes from older words meaning “to come near.” In aviation, it means the phase of flight where the aircraft is coming near the airport to land. “Clearance” means official permission from air traffic control, not just that the path is free of obstacles.
Why Pilots Care
It lets the pilot descend and follow the published procedure without waiting for further instructions until reaching the final approach segment or missed approach point.
Intuition Check
Do not read “clearance” as “everything ahead is clear.” Here it means official permission to fly the approach procedure. Also, an approach clearance is not automatically a landing clearance.
Example Sentence 1
Approaching the initial fix, the controller said, 'Cleared ILS Runway 27 approach,' and the pilot read back the approach clearance before beginning the descent.
Example Sentence 2
After receiving the approach clearance we started the descent checklist.