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. 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. About the Author: The Federal Aviation Administration (FAA) is an agency of the United States Department of Transportation with authority to regulate and oversee all aspects of civil aviation in the U.S. (National Airworthiness Authority). The Federal Aviation Act of 1958 created the group under the name "Federal Aviation Agency", and adopted its current name in 1967 when it became a part of the United States Department of Transportation. The Federal Aviation Administration's major roles include: Regulating U.S. commercial space transportation. Regulating air navigation facilities' geometry and Flight inspection standards. Encouraging and developing civil aeronautics, including new aviation technology. Issuing, suspending, or revoking pilot certificates. Regulating civil aviation to promote safety, especially through local offices called Flight Standards District Offices. Developing and operating a system of air traffic control and navigation for both civil and military aircraft. Researching and developing the National Airspace System and civil aeronautics. Developing and carrying out programs to control aircraft noise and other environmental effects of civil aviation.