Definition
Authorizations issued by air traffic control (ATC) granting a pilot permission to proceed under specified conditions within controlled airspace. A clearance typically includes a route, altitude, and any restrictions, and must be read back by the pilot to confirm correct receipt.
Plain English
Permission from air traffic control to fly a specific route, at a specific altitude, under specific conditions. The pilot reads it back so the controller knows it was heard and understood correctly.
Context Anchor
Used in radio communication with air traffic control, especially during instrument flight, taxi, departure, route changes, altitude changes, approach, and landing.
Derivation
From 'clear' — to make free or open the way. A clearance is literally the controller clearing a path through the airspace for that flight.
Why Pilots Care
A pilot must receive and correctly read back a clearance before entering controlled airspace or conducting IFR operations; failure to comply can result in loss of separation or regulatory violation.
Intuition Check
Do not read clearances as casual suggestions or general approval. In aviation, clearances are specific permissions with limits, conditions, and instructions the pilot must understand before acting.
Example Sentence 1
Before taxiing for an IFR departure, the pilot called clearance delivery and copied the full clearance, then read it back word for word.
Example Sentence 2
After receiving the takeoff clearance the pilot taxied onto the runway and departed.