National Airspace System
The National Airspace System (NAS) is the term used to represent the overall environment in which aircraft operate. This includes the aircraft itself, the pilots, the facilities, the tower controllers, the terminal area controllers, the enroute controllers, and the oceanic controllers. It includes the airports, the maintenance personnel and the airline dispatchers. All of this, with their computers, communications equipment, satellite navigation aids, and radars, are part of the NAS.
It covers every aspect of aviation in the United States, beginning with the aircraft itself. The Federal Aviation Administration (FAA) is charged with certifying the aircraft for safe operations. The FAA also certifies maintenance and repair operations, their practices and personnel, and even the certification of spare parts.
Airports are perhaps the most fundamental component of the NAS. No matter the size or complexity of an airport, FAA sets standards for construction and operation of airport facilities.
The NAS includes some 36,000 pieces of equipment operating in hundreds of locations throughout the United States. These can range from simple navigation beacons to very modern Air Route Traffic Control Centers that handle the enroute traffic. The mission of this highly integrated system is to support all phases of flight for aircraft in the United States, from initial flight planning to successful take off, enroute operations, and landing. The system provides communications, navigation, surveillance, display, flight planning, and weather data to controllers, traffic managers and pilots.
The NAS integrates a number of control facilities, radars, computers, and communications systems. Operated by the controller workforce, a staff of some 15,000, they control the aircraft in the system and provide critical data through every stage of their operations. Included in this are the towers themselves, the 171 Terminal Radar Approach Control Facilities throughout the United States, the Air Route Control Centers that control aircraft in the En Route environment and the three Oceanic Control Centers. All of these control centers are linked and managed through an Air Traffic Control System Command Center in Herndon, Virginia. All of these centers are operated and managed by FAA personnel.