Definition
An authorization issued by air traffic control (ATC) that permits a pilot to depart from an airport under specified conditions, typically including the assigned route, initial altitude, departure frequency, and transponder code. It is required before takeoff under instrument flight rules (IFR) and may also be issued for certain VFR operations from controlled airports.
Plain English
Permission from air traffic control to leave the airport, telling the pilot where to go, how high to climb at first, and which radio frequency and transponder code to use.
Context Anchor
You may receive a departure clearance before a flight from clearance delivery, ground control, a control tower, or another air traffic control facility.
Derivation
From Latin 'clarus' meaning 'clear.' A clearance is literally permission that 'clears' the way. In ATC use, it means the pilot has been cleared by the controller to proceed under stated conditions.
Why Pilots Care
It provides the legal and operational instructions needed to depart safely in controlled airspace and maintain separation from other traffic.
Intuition Check
Do not assume departure clearance means takeoff clearance. A departure clearance often tells you how to leave after takeoff; a separate takeoff clearance may still be required before you use the runway.
Example Sentence 1
Before taxi, the pilot called clearance delivery and received a departure clearance with a route, an initial altitude of 3,000 feet, and a departure frequency.
Example Sentence 2
After receiving the departure clearance, the crew set the assigned heading and altitude in the autopilot.