ATC Clearance
Definition
Authorization from air traffic control for an aircraft to proceed under specified conditions, including route, altitude, and speed. Pilots must receive clearance before taxiing, taking off, or landing.
Related Terms
Ground Control
The ATC position responsible for directing aircraft movement on taxiways and non-active runways at an airport. Coordinates with tower control for runway crossings.
Squawk Code
A four-digit code assigned by ATC and entered into an aircraft's transponder for identification on radar. Special codes include 7500 (hijack), 7600 (radio failure), and 7700 (emergency).
Transponder
An electronic device on an aircraft that receives radar signals and automatically transmits a response with identification and altitude information back to air traffic control.