air traffic services airspaces
Airspace of defined dimensions, alphabetically designated, within which specific types of flights may operate and for which air traffic services and rules of operations are specified (ICAO). ATC (air traffic control) airspaces are classified as Class A to G (in the United States, A to E and G). In these airspaces, types of flight—VFR or IFR, separation provided, VMC (visual meteorological conditions) visibility and distance from cloud minima, speed limitations, radio communications requirements, and whether the flights require an ATC clearance or not are specified.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved