a. This Glossary was compiled to promote a common understanding of the terms used in the Air Traffic
Control system. It includes those terms which are intended for pilot/controller communications. Those terms
most frequently used in pilot/controller communications are printed in bold italics. The definitions are primarily
defined in an operational sense applicable to both users and operators of the National Airspace System. Use of
the Glossary will preclude any misunderstandings concerning the system's design, function, and purpose.
b. Because of the international nature of flying, terms used in the Lexicon, published by the International
Civil Aviation Organization (ICAO), are included when they differ from FAA definitions. These terms are
followed by “[ICAO].” For the reader's convenience, there are also cross references to related terms in other parts
of the Glossary and to other documents, such as the Code of Federal Regulations (CFR) and the Aeronautical
Information Manual (AIM).
c. This Glossary will be revised, as necessary, to maintain a common understanding of the system.
EXPLANATION OF CHANGES
a. Terms Added:
GLOBAL NAVIGATION SATELLITE SYSTEM (GNSS [ICAO]
GLOBAL NAVIGATION SATELLITE SYSTEM MINIMUM EN ROUTE IFR ALTITUDE (GNSS MEA)
changes were made where necessary. Revision bars were not used due to
the insignificant nature of the changes.