Air Traffic Control and Navigation
In FY 1995, the FAA's Advanced Automation System (AAS) program underwent major restructuring to contain cost growth and minimize delays, and several new systems were introduced. The Display Systems Replacement program has begun to replace aged display channels, controller workstations, and network infrastructure by providing control room platforms for transition into other planned user benefit enhancements. Previously suspended, the Display Channel Complex Rehost program restarted its work to rehost existing display channel complex software from obsolete computer hardware to a new, more reliable and maintainable computer system. The FAA ordered a new digital Voice Switching and Control System for all air route traffic control centers and the FAA Academy to replace 30-year-old equipment. That project completed deployment readiness review and passed operational testing and evaluation during FY 1995. FAA personnel also continued work on the Standard Terminal Automation Replacement System to provide for any size terminal radar control (TRACON) while making maximum usage of standard commercial software and components. Engineers also made progress on the Automated Radar Terminal Systems program and the Tower Control Complex program for computer automation.
During FY 1995, the U.S. GPS achieved the final operating capability for civil aviation usage, and the FAA continued to certify additional GPS receivers. In August 1995, the FAA awarded a contract to Wilcox Electric Incorporated for the Wide Area Augmentation System (WAAS), a network of ground stations and communications systems designed to enhance the integrity and availability of GPS signals. The FAA's GPS-Navigation Integrated Product Team, with the FAA Technical Center, established the National Satellite Navigation Test Bed to continue operational demonstrations of evolving augmentation technologies and to validate developing software by the WAAS contractor.
In the military arena, GPS continued to be deployed fully, with complete worldwide availability to the U.S. armed forces. GPS allows accurate, instantaneous positioning for military forces and supports a new generation of smart, highly accurate weapon systems. Of particular note in FY 1995, DoD began to integrate GPS into the survival radios for U.S. pilots, allowing rescue forces to locate and communicate with downed personnel without compromising their location. The Army agreed to buy 95,000 GPS sets for their forces, while the Navy and Air Force followed similar paths.
Engineers at the Institute for Telecommunications Sciences, part of NTIA, were instrumental in developing a national plan to augment navigation signals from GPS, a satellite program managed by DoD. By providing more accurate and reliable GPS signals, a wide variety of transportation modes will be served, and a large economic and technological impact is expected to occur.
The FAA continued to conduct flight tests for developing criteria for nonprecision GPS approach terminal instrument procedures to be employed at heliports. This effort resulted in 35 lives being saved in 1 year at a single test site in Chattanooga, Tennessee, where the world's first helicopter nonprecision GPS approach was certified. Because a helicopter was able to arrive quickly at the trauma center under poor weather conditions, these lives were saved. The FAA is participating with NASA, DoD, and industry to promote and expand the U.S. rotorcraft technology base to improve safety and expand operations. The FAA is also working with the Civil Tiltrotor Development Advisory Committee to ascer tain the pros and cons of developing a civil tiltrotor transportation system in the United States.
FAA personnel continued their work on the multi-element Terminal Air Traffic Control Automation (TATCA) program, which provides computer automation to assist controllers in traffic flow management in the airspace surrounding major airports. This automation technology benefited users through improved airspace capacity, reduced delays, fuel savings, and enhanced controller productivity. The Converging Runway Display Aid (CRDA) component of TATCA allows continued use of paired aircraft on intersecting runways during instrument meteorological conditions. After successfully implementing CRDA at six airports, FAA personnel proceeded to adapt it for five additional terminal facilities. During FY 1995, engineers completed the first research and development phase of the controller automated spacing aid, which enhances CRDA capabilities to separate precisely aircraft that are on merging paths. The third main element of TATCA is the Center-TRACON Automation System (CTAS), a package of software components that was developed by the FAA and NASA. The CTAS design strategy shifted from individual software development to an integrated packaging approach with other traffic flow management products. FAA personnel would like to integrate CTAS with other traffic flow management systems, such as the automated enroute air traffic control system, the departure sequencing program, the surface movement advisor, and the traffic management system.
NASA and United Airlines conducted flight tests to evaluate and validate a software tool called the Descent Advisor, one of the elements that make up CTAS. CTAS increases the efficiency of air traffic control by giving flight controllers a better awareness of traffic flows. NASA's Boeing 737 TSRV flew 24 CTAS test runs in the Denver terminal area to identify and quantify sources of prediction errors in the Descent Advisor software and to investigate guidance concepts for a new flight management system. Technicians equipped the aircraft with air data and navigation systems that measured the aircraft's location and flight condition to accuracies not possible with current air traffic control radars. All participants, including airport flight controllers, the FAA, airport management, and NASA were enthusiastic about the system and the test results. Investigators performed the CTAS flight tests under a joint research and development effort involving the FAA, NASA's ARC and LaRC, the National Center for Atmospheric Research, several aerospace contractors, and United Airlines.
The FAA required the Traffic alert and Collision Avoidance System (TCAS) I, a low-power system that provides alerting and unrecommended escape maneuvers, in turbine-powered commercial airplanes with 10 to 30 passenger seats by the end of 1995. Public Law 100-236 already required that all air carrier aircraft with more than 30 passengers seats, operating in U.S. airspace, be equipped with TCAS II. TCAS II alerts the pilots to traffic and advises whether to climb or descend when a potential conflict occurs; pilots have reported that the system has already prevented midair collisions. In FY 1995, the FAA continued to monitor the technical and operational performance of TCAS I and TCAS II and to make adjustments as necessary.
The FAA's Terminal Area Surveillance System program provided a single-system replacement for the current mix of multiple aircraft and weather terminal surveillance systems. In FY 1995, that program conducted research on, and technology demonstrations of, design concepts expected to provide enhanced capabilities to increase capacity, efficiency, and safety. Focus areas included seamless surveillance, timely hazardous weather prediction and detection, and full-volume coverage while providing for lower maintenance costs and accommodating site-specific needs. The FAA also completed a cost-benefit analysis of alternative concepts and began cost-performance trades and simulations for an S/C-band single-array radar design. In addition, the FAA began an evaluation of Russian phased-array technology and U.S. computer hardware/software technology and began trade studies on a radar for low- and medium-density airports.
During FY 1995, FAA personnel expanded the Tower Data Link Service to a total of 57 airports. Demonstrations of Graphical Weather Services and Traffic Information Services begun in 1995 are to lead to a regional evaluation program and then national implementation. FAA personnel also demonstrated Terminal Weather Information for Pilots at six sites. In addition, FAA managers defined the requirements for the Initial Terminal Data Link and authorized the development of software. The development of the Key Site in the Gulf of Mexico to support Automatic Dependent Surveillance-Broadcast (ADS-B) using GPS Squitter signals continued as well. FAA personnel also worked toward the development of U.S. and international standards for controller/pilot data link communications to standardize interfaces for digital messages for air traffic communications services, helping to relieve pilot and controller workload while reducing voice channel congestion. In addition, the FAA supported the development of the context management applications, which enable aircraft and ground systems to maintain up-to-date addressing information while an aircraft is in flight.
During the fiscal year, the FAA began end-to-end testing of the prototype oceanic data link by testing an air traffic services interfacility data communications system as a prototype for ground-to-ground data link communications between adjacent Flight Information Regions. Additionally, the Department of Air Transport for the Russian Federation agreed to permit the FAA to install a prototype air traffic services interfacility data communications system in the Russian far east and connect it to the Anchorage Air Route Traffic Control Center. The FAA also participated in the development of dynamic aircraft route planning capability in the South Pacific for the rerouting of aircraft in midflight.
During FY 1995, the FAA Technical Center in Atlantic City provided national airspace simulation capability support for developing operational procedures for the New York Air Route Traffic Control Center. This is to accommodate the anticipated change from a 2,000-foot to a 1,000-foot vertical separation standard in the North Atlantic Minimum Navigation Performance Specification airspace. Air traffic controllers are faced with the problem of positioning aircraft between portions of airspace in which various vertical separation minima apply, coupled by the lack of radar coverage in the transition areas.
The FAA Technical Center also assisted in validating procedures for the use of TCAS as an aid in ensuring adequate separation between a pair of same-route oceanic aircraft at different altitudes to allow the trailing aircraft, at a lower altitude than the leading aircraft, to climb to an altitude above the leading aircraft with less along-track separation than normally required under International Civil Aviation Organization procedures.
During FY 1995, the FAA Technical Center and the Integrated Product Team for Aircraft and Avionics determined whether the display of both indicated air speed and ground speed for a leading aircraft is needed by the crew of a trailing aircraft to maintain station during an instrument approach. This study supported the FAA initiative regarding pilot situational awareness when operating in a stationkeeping mode during final approach. These supported the Minimum Aviation System Performance Standards for ADS-B technology, which provides position and air speed information to the trailing aircraft.
In addition, the FAA Technical Center National Simulation Capability worked toward defining and developing a common set of air traffic communication protocols and standards and a highly reliable network architecture to support large-scale human in-the-loop simulations. DoD assisted in defining an Air Traffic Control Simulation Protocol.
Curator: Lillian Gipson|
Last Updated: September 5, 1996
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