Deregulation of the U.S. airline industry has resulted in ticket prices dropping by a third, on an inflation-adjusted basis. As a result some 1.6 million people fly on 4,000 aircraft every day. Airlines carried 643 million passengers in 1998, a 25% increase over 1993 and the FAA estimates that the nation??s airline system will have to accommodate 917 million passengers by the year 2008. The growth in air travel threatens to overwhelm the presently inadequate air traffic control system, which has not kept pace with available technology in navigation, communications, and flight surveillance. Much of the equipment used for air traffic control today is based on fifty-year-old technology; for example, analog simplex voice links for communications and ground-based radar for surveillance, and VHF Omnidirectional Range/Distance Measuring Equipment (VOR/DME) for navigation. The lack of system automation imposes heavy workloads on human air traffic controllers and increases the risk of accidents in heavy traffic situations.
Capacity limits are being reached in both airports and airspace, with congestion delays in departure and arrival schedules reaching record numbers. Funds to upgrade the air traffic control system are available in the trust fund created to receive the tax applied to airline passenger tickets and the tax on fuel for general aviation. The General Accounting Office says modernizing the air traffic control system will cost at least 17 billion for just the first 5 years of the FAA??s 15-year National Airspace System improvement plan. It is the NAS that provides the services and infrastructure for air transportation. Air transportation represents 6% of the Nation??s gross domestic product, so the NAS is a critical element of our national economy.
Given the size of the NAS, the task ahead is enormous. Our NAS includes more than 18,300 airports, 21 air route traffic control centers, over 460 air traffic control towers and 75 flight service stations, and approximately 4,500 air navigation facilities. The NAS spans the country, extends into the oceans, and interfaces with neighboring air traffic control systems for international flights. The NAS relies on approximately 30,000 FAA employees to provide air traffic control, flight service, security, and field maintenance services. More than 616,000 active pilots operating over 280,000 commercial, regional, general aviation and military aircraft use the NAS.
On March 11, 1999, the FAA released the NAS Architecture Version 4.0 to the public. Key influences on the architecture include the 1996 White House Commission on Aviation Safety and Security, which recommended that the FAA accelerate modernization of the NAS, and the 1997 National Civil Aviation Review Commission, which recommended funding and performance management methods for implementing NAS modernization. It describes the agency??s modernization strategy from 1998 through 2015. Based on the Free Flight operational concept, Version 4.0 contains capabilities, technologies, and systems to enhance the safety of the aviation system and provide users and service providers with more efficient services. Free Flight centers on allowing pilots, whenever practical, to choose the optimum flight profile. This concept of operations is expected to decrease user costs, improve airspace flexibility, and remove flight restrictions.
The NAS Architecture is divided into three modernization phases and its implementation is being synchronized with the International Civil Aviation Organization to ensure interoperability and global integration.
?h Phase 1 (1998-2002) focuses on sustaining essential air traffic control services and delivering early user benefits. Free Flight Phase 1 will be implemented. Controller computer workstations will begin major upgrades. Satellite-based navigation systems will be deployed, and air-to-air surveillance will be introduced. The ??Year 2000?? computer problem will hopefully be fixed.
?h Phase 2 (2003-2007) concentrates on deploying the next generation of communications, navigation and surveillance (CNS) equipment and the automation upgrades necessary to accommodate new CNS capabilities. Satellite-based navigation systems will be further augmented in local areas for more precise approaches. New digital radios that maximize the spectrum channels will be installed. As users equip, automatic dependent surveillance ground equipment will be installed to extend air traffic control surveillance services to non-radar areas. Tools from Phase 1 will be deployed throughout the NAS and upgraded as necessary.
?h Phase 3 (2008-2015) completes the required infrastructure and integration of automation advancements with the new CNS technologies, enabling additional Free Flight capabilities throughout the NAS. Two important features will be NAS-wide information sharing among users and service providers and ??four-dimensional?? flight profiles that utilize longitudinal and lateral positions and trajectories as a function of time.
The goals for modernizing the NAS are based on improving:
?h Safety ?V such as better weather information in the cockpit and on controller displays.
?h Accessibility ?V such as instrument approaches to many more airports.
?h Flexibility ?V such as allowing users to select and fly desired routes.
?h Predictability ?V such as meeting flight schedules even in adverse weather conditions.
?h Capacity ?V such as increasing aircraft arrival rates to airports.
?h Efficiency ?V such as saving fuel by reducing taxing times to/from the runways.
?h Security ?V such as controlling access to facilities and critical information systems.
The NAS Architecture is essential to the FAA and the aviation community because it provides the most detailed guide ever for planning operations and making NAS-related investment decisions. The Blueprint and Version 4.0 will be updated in response to changing needs, research results, new technology, and funding.
NAS modernization involves providing new systems to enhance capabilities and services for users. Modernization also includes making the critical infrastructure of air traffic control services easier and more cost-effective to operate and maintain. Critical infrastructure includes:
?h Communications, navigation/landing and radar surveillance systems
?h Weather detection and reporting equipment
?h Air traffic control computers and displays for controllers
?h Power generation and backup systems
?h Air traffic control facilities sustainment
Here is a brief summary of key NAS systems/capabilities and their architectural improvements:
Communications
Aviation communications systems will be upgraded, integrating systems into a seamless network using digital technology for voice and data. During the transition, the FAA will continue to support analog voice communications. A major improvement will be controller-pilot data link communications (CPDLC), which introduces electronic data exchange between controllers and the cockpit and reduces voice-channel congestion.
Navigation
Over the next 10 years, the navigation system is expected to use satellites augmented by ground monitoring stations to provide navigation signal coverage throughout the NAS. Reliance on ground-based navigation aids is expected to decline as satellite navigation provides equivalent levels of service. The transition to satellite-based navigation consists of:
?h Use of the global positioning system (GPS) as a supplemental system for en route navigation and non-precision approaches.
?h Deployment of the wide area augmentation system (WAAS) to augment GPS for primary means en route navigation and precision approaches. WAAS will be deployed in stages by adding ground reference stations, with operational capability improving in each stage.
?h Deployment of a local area augmentation system (LAAS) to augment GPS for precision approaches in low visibility conditions.
Surveillance
Surveillance in the future NAS will provide increased coverage in non-radar areas and includes aircraft-to-aircraft capabilities for greater situation awareness. The NAS Architecture calls for gradual transition from current radar systems to digital radar and automatic dependent surveillance (ADS).
Aviation Weather
The NAS Architecture contains improved ways to collect, process, transmit, and display weather information to users and providers, during flight planning and in flight. The goal is to give NAS providers and users depictions of weather information and provide more weather data in the cockpit to enhance common situation awareness.
Avionics
Avionics will evolve to take advantage of new communications, navigation, and surveillance-related technologies in the NAS Architecture, including:
?h New multi-mode digital radios for voice and data communications among pilots, controllers and various ground facilities.
?h Digital communications technology that increases available voice channel capacity and provides a data link which enables instructions, flight information services, and graphical weather data to be sent directly to the cockpit.
Free Flight Phase 1
New tools that give controllers, planners and service operators more complete information about air traffic control and flight operations comprise a large part of the NAS Architecture??s near-term plan. Some of these tools are embodied in a program called Free Flight Phase 1 Select Capability/Limited Deployment. The Free Flight 1 tools are:
?h User request evaluation tool/core capability limited deployment (URET CCLD) ?V an automated tool that assists en route controllers in identifying conflicts up to 20 minutes in advance of their occurrence.
?h Traffic management advisor (TMA) single center ?V an automated tool that assists en route radar controllers with sequencing aircraft to terminal areas.
?h Passive final approach spacing tool (pFAST) ?V an automated tool designed to work in conjunction with TMA to help controllers assign runways and sequence aircraft according to user preferences and airport capacity.
?h Collaborative decision-making (CDM) ?V a real-time exchange of flight plan and system constraints data between the FAA and airline operations centers in order to work collaboratively to better manage NAS traffic.
?h Surface movement advisor (SMA) ?V a system that provides information sharing to airline and airport personnel who plan and manage the sequence of taxi out and plan for arrivals in the ramp and gate areas at larger airports.
Automation Infrastructure
Free Flight Phase 1 tools and other future tools depend on infrastructure improvements already underway, such as the display system replacement (DSR), standard terminal automation replacement system (STARS) and host/oceanic computer system replacement (HOCSR), to operate.
DSR provides new controller workstations and a network infrastructure for the air route traffic control centers (ARTCC). DSR has the capability to show weather data from the next generation weather radar. STARS is the new terminal workstation that will interface with the new sequencing and spacing tools and the advanced communications, navigation, surveillance and weather systems. HOCSR replaces the host and oceanic processors and peripherals at the ARTCCs to solve immediate hardware supportability problems.
Since the early 1980s, efforts by the FAA to modernize the air traffic control system have experienced lengthy schedule delays and substantial cost overruns. There is a belief held by many that the above procurement and personnel reforms, while useful, are not likely to change the FAA??s bureaucratic corporate culture. And they do not address the inherent problems of the ATC system being part of the federal budget process, subject to external micromanagement, and subject to a conflict of interest between safety regulation and ATC operations. They believe the United States should follow the example of Britain, Germany, Switzerland and most recently, Canada, in fundamentally restructuring air traffic control. It is their opinion that a not-for-profit user-controlled, user-funded corporation is the best way to address the ATC system??s fundamental problems.
We find ourselves with a system that currently runs on obsolete and failure-prone equipment such as 1960s mainframe computers, equipment dependent on vacuum tubes, and radar between twenty and thirty years old. The FAA maintains safety margins by artificially increasing the spacing between flights, imposing ground holds and using other techniques that reduce system capacity. The airlines alone waste $3 billion a year in fuel and crew time due to the delays. Wasted passenger time is estimated at several billion dollars more. The FAA??s National Airspace System Architecture Version 4.0 looks very impressive on paper, but given their track record in regards to modernization, maybe we should be looking at alternatives to a thinly stretched bureaucracy.
