ATC Clearence
Authorisation for an aircraft to proceed under conditions specified by an air traffic control unit.
Clearance Limit
The point to which an aircraft is granted an air traffic control clearance.
ATC Instructions
Directives issued by air traffic control for the purpose of requiring a pilot to take a specific action.
Holding Fix
A geographical location, identified by visual or other means that serves as a reference for a holding procedure.
Holding Procedure
A predetermined manoeuvre which keeps an aircraft within a specified airspace whilst awaiting further clearance.
Separation
Spacing between aircraft, levels or tracks.