This glossary is written for virtual airline and flight simulation use within Virtual Air Canada Airline. It is not intended as a real-world aviation reference.
ATC
Air Traffic Control
Air Traffic Control (ATC) is the ground-based service responsible for directing the movement of aircraft in controlled airspace and on the ground at airports. Its primary objective is to prevent collisions between aircraft, between aircraft and obstacles, and to maintain an orderly and expeditious flow of air traffic. ATC is organized into several functional areas: ground control manages aircraft on taxiways and aprons; tower control handles aircraft in the immediate airport environment during takeoff and landing; approach and departure controls manage aircraft transitioning between the terminal area and en-route structure; and area control centers (ACCs) or en-route centers handle aircraft during the cruise phase over large geographic areas.
Controllers issue clearances, instructions, and traffic information using standardized radiotelephony phraseology defined by ICAO and regional authorities. Pilots are required to read back specific instructions - such as runway assignments, altitude clearances, and transponder codes - to confirm receipt and understanding. ATC separation standards vary by airspace class, phase of flight, and equipment capability, and can be based on radar, ADS-B, procedural separation, or a combination. TCAS (Traffic Collision Avoidance System) aboard the aircraft provides an independent layer of collision protection and operates independently of ATC.