Today’s National Airspace System (NAS) consists of a • Approximately 13,000 instrument flight proce- complex collection of facilities, systems, equipment, dures, including over 1,000 Instrument Landing procedures, and airports operated by thousands of peo- System (ILS) procedures, over 1,700 nondirec- ple to provide a safe and efficient flying environment. tional beacon (NDB) procedures, over 2,700 VHF The NAS includes: omnidirectional range (VOR) procedures, and over 3,500 global positioning system/area naviga- • More than 750 air traffic control (ATC) facilities tion procedures (GPS/RNAV). with associated systems and equipment to provide • Procedures such as microwave landing system radar and communication service. (MLS), localizer (LOC), localizer type directional aid (LDA), simplified directional facility (SDF), • Volumes of procedural and safety information nec- charted visual flight procedures, departure proce- essary for users to operate in the system and for dures (DPs), and standard terminal arrivals FAA employees to effectively provide essential (STARs). services. • Approximately 2,153,326 instrument approaches • More than 18,000 airports capable of accommo- annually, of which 36 percent are air carrier, 27 dating an array of aircraft operations, many of percent air taxi, 33 percent general aviation, and 4 which support instrument flight rules (IFR) depar- percent military. tures and arrivals. • Approximately 49,409,000 instrument operations logged by FAA towers annually. • Approximately 4,500 air navigation facilities. America’s aviation industry is projecting continued • Approximately 48,000 FAA employees who pro- increases in business, recreation, and personal travel. vide air traffic control, flight service, security, Airlines in the United States (U.S.) expect to carry twice field maintenance, certification, systems acquisi- as many passengers by the year 2015 as they do today. tions, and a variety of other services. [Figure 1-1] Figure 1-1. IFR Operations in the NAS. 1-1 BRIEF HISTORY OF THE operations at airports. Later, the addition of radar helped NATIONAL AIRSPACE SYSTEM controllers to keep abreast of the postwar boom in com- About two decades after the introduction of powered mercial air transportation. flight, aviation industry leaders believed that the air- plane would not reach its full commercial potential with- The introduction of jet airliners, followed by a series of out federal action to improve and maintain safety midair collisions, instigated the passage of the Federal standards. In response to their concerns, the U.S. Aviation Act of 1958, which transferred CAA functions Congress passed the Air Commerce Act of May 20, to the FAA (then the Federal Aviation Agency). The act 1926, marking the onset of the government’s hand in entrusted safety rulemaking to the FAA, which also held regulating civil aviation. The act charged the Secretary the sole responsibility for developing and maintaining a of Commerce with fostering air commerce, issuing and common civil-military system of air navigation and air enforcing air traffic rules, licensing pilots, certifying air- traffic control. In 1967, the new Department of craft, establishing airways, and operating and maintain- Transportation (DOT) combined major federal trans- ing aids to air navigation. As commercial flying portation responsibilities, including the FAA (now the increased, the Bureau of Air Commerce—a division of Federal Aviation Administration) and a new National the Department of Commerce—encouraged a group of Transportation Safety Board (NTSB). airlines to establish the first three centers for providing air traffic control (ATC) along the airways. In 1936, the By the mid-1970s, the FAA had achieved a semi-auto- bureau took over the centers and began to expand the mated ATC system based on a marriage of radar and ATC system. [Figure 1-2] The pioneer air traffic con- computer technology. By automating certain routine trollers used maps, blackboards, and mental calculations tasks, the system allowed controllers to concentrate to ensure the safe separation of aircraft traveling along more efficiently on the task of providing aircraft separa- designated routes between cities. tion. Data appearing directly on the controllers’ scopes provided the identity, alti- tude, and groundspeed of air- craft carrying radar beacons. Despite its effectiveness, this system required continuous 1946 enhancement to keep pace with the increased air traffic of the late 1970s, due in part to the competitive environ- ment created by airline deregulation. To meet the challenge of traffic growth, the FAA unveiled the NAS Plan in January 1982. The new plan called for more advanced systems for en route and ter- minal ATC, modernized flight service stations, and improvements in ground-to- air surveillance and commu- nication. Continued ATC modernization under the NAS Plan included such steps as the implementation 1970-2000 of Host Computer Systems (completed in 1988) that Figure 1-2. ATC System Expansion. were able to accommodate new programs needed for the future. [Figure 1-3] On the eve of America’s entry into World War II, the Civil Aeronautics Administration (CAA)—charged with In February 1991, the FAA replaced the NAS Plan with the responsibility for ATC, airman and aircraft certifi- the more comprehensive Capital Investment Plan (CIP), cation, safety enforcement, and airway development— which outlined a program for further enhancement of the expanded its role to cover takeoff and landing ATC system, including higher levels of automation as well 1-2 • Airport weather conditions. • En route severe weather. The goal of the OEP is to expand capacity, decrease delays, and improve efficiency while main- taining safety and security. With reliance on the strategic support of the aviation community, the OEP is limited in scope, and only contains programs to be accomplished between 2001 and 2010. Programs may move faster, but the OEP sets the minimum schedule. Considered a living docu- ment that matures over time, the OEP is continually updated as deci- sions are made, risks are identified and mitigated, or new solutions to operational problems are discovered through research. An important contributor to FAA plans is the Terminal Area Operations Aviation Rulemaking Committee (TAOARC). The objec- tives and scope of TAOARC are to Figure 1-3. National Airspace provide a forum for the U.S. aviation System Plan. community to discuss and resolve issues, provide direction for U.S. as new radar, communications, and weather forecasting flight operations criteria, and produce U.S. consensus systems. One of the CIP’s programs currently underway is positions for global harmonization. the deployment of new Terminal Doppler Weather Radar systems able to warn pilots and controllers of meteorologi- The general goal of the committee is to develop a means cal hazards. The FAA is also placing a high priority on to implement improvements in terminal area operations speeding the application of the GPS satellite technology to that address safety, capacity, and efficiency objectives, as civil aeronautics. Another notable ongoing program is tasked, that are consistent with international implemen- encouraging progress toward the implementation of tation. In the context of this committee, terminal area Free Flight, a concept aimed at increasing the efficiency means the airspace that services arrival, departure, and of high-altitude operations. airport ground operations. This committee provides a forum for the FAA, other government entities, and NATIONAL AIRSPACE SYSTEM PLANS affected members of the aviation community to discuss FAA planners efforts to devise a broad strategy to issues and to develop resolutions and processes to facil- address capacity issues resulted in the Operational itate the evolution of safe and efficient terminal area Evolution Plan (OEP)the FAA’s commitment to meet operations. the air transportation needs of the U.S. for the next ten Current efforts associated with NAS modernization years. come with the realization that all phases must be inte- grated. The evolution to an updated NAS must be well To wage a coordinated strategy, OEP executives met with orchestrated and balanced with the resources available. representatives from the entire aviation community— Current plans for NAS modernization focus on three key including airlines, airports, aircraft manufacturers, service categories: providers, pilots, controllers, and passengers. They agreed on four core problem areas: • Upgrading the infrastructure. • Providing new safety features. • Arrival and departure rates. • Introducing new efficiency-oriented capabilities • En route congestion. into the existing system. 1-3 It is crucial that our NAS equipment is protected, as lost commonly referred to as ADS-B, is a signal that can radar or communications signals can slow the flow of be received by other properly equipped aircraft and aircraft to a busy city, which in turn, could cause delays ground receiver stations, which in turn feed the throughout the entire region, and possibly, the whole automation system accurate aircraft position informa- country. tion. This more accurate information will be used to improve the efficiency of the system—the third cate- The second category for modernization activities gory of modernization goals. focuses on upgrades concerning safety. Although we cannot control the weather, it has a big impact on the Other key efficiency improvements are found in the NAS. Fog in San Francisco, snow in Denver,