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more profitable. Thus, within a few years, most
regional air traffic in the continental U.S. will be by
jet, with turboprops filling a smaller role.
FAA and industry studies have investigated the underlying operational and economic environments of RJs on the
ATC system. They have revealed two distinct trends: (1)
growing airspace and airport congestion is exacerbated by
the rapid growth of RJ traffic, and (2) potential airport
infrastructure limitations may constrain airline business.
The FAA, the Center for Advanced Aviation System
Development (CAASD), major airlines, and others are
working to find mitigating strategies to address airline
congestion. With nearly 2,000 RJs already in use—and
double that expected over the next few years—the success of these efforts is critical if growth in the regional
airline industry is to be sustained. [Figure 1-8]
CORPORATE AND FRACTIONAL OWNERSHIPS
Though technically considered under the GA umbrella,
the increasing use of sophisticated, IFR-equipped aircraft
by businesses and corporations has created a niche of its
own. By using larger high performance airplanes and
equipping them with the latest avionics, the business
portion of the GA fleet has created demands for ATC
services that more closely resemble commercial operators than the predominately VFR general aviation fleet.
GENERAL AVIATION
The tendency of GA aircraft owners to upgrade the performance and avionics of their aircraft increases the
demand for IFR services and for terminal airspace at airports. In response, the FAA has increased the extent of
controlled airspace and improved ATC facilities at major
airports. The safety of mixing IFR and VFR traffic is a
major concern, but the imposition of measures to separate and control both types of traffic creates more restrictions on airspace use and raises the level of aircraft
equipage and pilot qualification necessary for access.
MILITARY
From an operational point of view, military flight activities comprise a subsystem that must be fully integrated
within NAS. However, military aviation has unique
requirements that often are different from civil aviation
users. The military’s need for designated training areas
and low-level routes located near their bases sometimes
conflicts with civilian users who need to detour around
these areas. In coordinating the development of ATC
systems and services for the armed forces, the FAA is
challenged to achieve a maximum degree of compatibility between civil and military aviation objectives.
ATC FACILITIES
FAA figures show that the NAS includes more than
18,300 airports, 21 ARTCCs, 197 TRACON facilities,
over 460 air traffic control towers (ATCTs), 58 flight
service stations and automated flight service stations
(FSSs/AFSSs), and approximately 4,500 air navigation
facilities. Several thousand pieces of maintainable
equipment including radar, communications switches,
ground-based navigation aids, computer displays, and
radios are used in NAS operations, and NAS components represent billions of dollars in investments by the
government. Additionally, the aviation industry has
invested significantly in ground facilities and avionics
systems designed to use the NAS. Approximately
47,000 FAA employees provide air traffic control, flight
service, security, field maintenance, certification, system acquisition, and other essential services.
Differing levels of ATC facilities vary in their structure and purpose. Traffic management at the national
level is led by the Command Center, which essentially “owns” all airspace. Regional Centers, in turn,
sign Letters of Agreement (LOAs) with various
approach control facilities, delegating those facilities
chunks of airspace in which that approach control
facility has jurisdiction. The approach control facilities, in turn, sign LOAs with various towers that are
within that airspace, further delegating airspace and
Figure 1-8. Increasing use of regional jets is expected to have
a significant impact on traffic.
1-10
responsibility. This ambiguity has created difficulties
in communication between the local facilities and the
Command Center. However, a decentralized structure
enables local flexibility and a tailoring of services to
meet the needs of users at the local level. Improved
communications between the Command Center and
local facilities could support enhanced safety and
efficiency while maintaining both centralized and
decentralized aspects to the ATC system.
AIR ROUTE TRAFFIC CONTROL CENTER
A Center’s primary function is to control and separate
air traffic within a designated airspace, which may cover
　
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