CAASD has been working closely with the FAA and other parties to develop and assess various near-term terminal area procedures with the aim of improving airline service. One result of CAASDs work is TARGETS (or Terminal Area Route Generation, Evaluation, and Traffic Simulation), a research tool that, has been used to interactively design routes with controllers and pilots. TARGETS has also been used for route assessment, for design refinement from flight tests, and for controller familiarization with new procedures. TARGETS aids RNAV (Area Navigation) route definition in several ways: - By displaying the route on the video map used by controllers.
- By deriving latitude and longitude coordinates for the proposed waypoints based upon video map location.
- By performing preliminary flyability checks for user-supplied aircraft performance characteristics.
Using TARGETs traffic simulation capability, controllers can familiarize themselves with the new procedure and examine mixed equipage issues and other operational issues such as taking an aircraft on the route, and sequencing and merging aircraft onto the RNAV. With CAASD assistance, controllers for several sites created traffic scenarios to familiarize themselves with such operational issues. TARGETS consists of a route definition capability, as well as a terminal area traffic simulation.  By simply pointing and clicking the mouse to derive latitude and longitude coordinates (and simultaneously creating the desired flight path), TARGETS allows airspace planners and procedure developers to instantaneously define an RNAV Departure Procedure (DP), Standard Terminal Arrival Route (STAR), or an approach. Altitude and/or speed control application is simple and can be easily changed (or, in controller parlance, "amended"). - The Evaluation or "flyability" check is a true time saver with respect to understanding the feasibility of the new RNAV procedure. TARGETS users can instantaneously analyze the procedures flyability (which is based on speed/altitude constraints and aircraft performance).
- The procedure developer can import topographical map data and/or specify restricted airspace areas to maximize airspace development while designing a procedure that is environmentally sensitive.
- The terminal traffic simulation capability of TARGETS assists controllers in becoming familiar with the new RNAV procedure. The TARGETS workstation can be installed in any air traffic control facility for controller training and route familiarization activities.
The Philadelphia Story To step back to where things were in the system before RNAV was implemented, terminal airspace constraints imposed as miles-in-trail restrictions at the TRACON (Terminal Radar Approach Control) entry/exit fixes require ad hoc vectoring of aircraft. This is required not only to fly in the airspace where routes are not defined, but also to achieve required aircraft separations. But flying over extended paths results in additional flight times and higher fuel costs. To minimize the variances between desired versus actual flight paths and to improve air transportation predictability and reliability, routes or paths need to be defined to and from the airport prior to established en route phases of flight. Today, CAASD is working collaboratively with the FAA, air carriers, air traffic controllers, the National Air Traffic Controllers Association (NATCA), and Jeppesen utilizing the TARGETS tool, as well as facilitating and documenting a repeatable RNAV development process. TARGETS and the repeatable process have demonstrated favorable results. TARGETS has expedited the RNAV development and implementation process, and has assisted ATC with controller familiarization and controller acceptance. Addressing the Problem(s) Prior to the development of RNAV routes, aircraft traveling to and from the Philadelphia airport often suffered from poor on-time performance, disrupted bank (aircraft fleet) schedules, and passenger delays. One primary reason for these problems was the mandatory miles-in-trail restrictions at the Terminal Radar Approach Control (TRACON) entry/exit fixes. These restrictions required costly, time-consuming procedures including more voice communication between controllers and pilots and ad hoc vectoring of aircraft. To remedy the problem, CAASD developed the Terminal Area Route Generation, Evaluation and Traffic Simulation (TARGETS), a subset of the Terminal Route Using Speed Control Techniques (TRUST) system, and adapted it specifically for use in TRACON airspace. TARGETS enabled CAASD to design efficient and reliable paths for airplanes to fly. Its efficient because it benefits fuel economy and airspace use. At the same time, yet it is reliable enough to allow for reduced communications between pilots and air traffic controllers because the controllers know the exact position of the plane. The Project The project began with the formation of the Philadelphia RNAV route development team. The team, comprising representatives from the FAA, the Philadelphia Tower/TRACON, US Airways, Inc., and CAASD, was tasked with defining more efficient routes to and from the airport. Since its initial meeting in Philadelphia in February 1999, CAASD has taken a major role in the design and assessment of the RNAV route One of CAASDs primary tasks on this project was creating and documenting the RNAV implementation process and project steps. The teams work included the development of a repeatable process to ensure that necessary activities are completed, major milestones are met, tasks are assigned and completed, and that the overall process is critical-path observant, streamlined, and efficient. It would be hard to overestimate the importance of the repeatable process; it reduces implementation time from two or more years to approximately eight months. Beyond the development of the repeatable process, CAASD also adapted TARGETS for the terminal area. The team used TARGETS to define the RNAV route by depicting the route profile, deriving latitude and longitude coordinates for the proposed waypoints, and running preliminary flyability checks with respect to aircraft performance characteristics. The new RNAV route permits equipped aircraft to self-navigate all the way to touchdown. By contrast, aircraft unequipped with Area Navigation capabilities fly the conventional vectors. This new approach reduces the number of controller clearances (voice communications) from approximately eight to two or three. Reduced voice communications will both increase efficiency and reduce workload. Furthermore, since the controllers know precisely where the aircraft are flying, situational awareness will also be improved. [Q: Do they not with conventional navigation?] In addition, because the route permits the aircraft to self-navigate to touchdown, there are fewer altitude crossing restrictions and required speed assignments. The result is a more predictable flight path than what pilots and controllers are used to today. Another major CAASD contribution to the project involves the successful installation of the TARGETS system at the Philadelphia airport and the subsequent training of air traffic controllers in using the new RNAV procedure. Phase I route development consisted of a route that overlays the conventional paths used by controllers for inbound flights. The CAASD team played a major role in developing software tools for TARGETS, and helped Philadelphia controllers learn to use the route design tool to define waypoints for an RNAV approach to a specific runway. Preliminary Results and Future Developments The preliminary results are very positive. As part of the TARGETS team, CAASD staff worked with a wide variety of people throughout Phase I. The exposure to all sides of the project has given us a unique perspective on the process of defining RNAV procedures within terminal airspace. This perspective is a vital part of solving the problem since the procedures defined must satisfy every requirement presented in order to be implemented and used effectively. A 30-day live field trial utilizing US Airways revenue flights occurred in the summer of 1999. The RNAV route is now being flown by US Airways, wind and weather permitting, on a regular basis. Furthermore, the special approach plate has been made available for use by all other carriers that are properly equipped. [UPDATE: The other carriers will be advised of the new RNAV route and will be asked to have their crews prepare to fly the route on a common date, expected to be in fall of 1999.] Future developments include an expansion of the route development process that will delineate other arrival and departure routes at the Philadelphia airport. In addition, CAASD has begun RNAV route development activities at the Newark airport (New York TRACON) with flight tests occurring on the new arrival routes this summer. RNAV development work at two more sites is scheduled for the year 2000. Area Navigation (RNAV) Procedures Using RNAV procedures in busy, congested terminal airspace has great potential to improve situational awareness, reduce delays, increase user/provider efficiencies, and to alleviate certain existing noise concerns. These benefits can be realized in terminal areas where a significant segment of the aircraft population is equipped with advanced avionics, such as Flight Management Computer Systems (FMCS). The FMCS provides flight planning and performance management, navigation database storage and retrieval, precise navigation and guidance, and interface with other aircraft systems. These advanced systems can permit an aircraft to fly a more accurate and predictable flight path to or from an airport. Both users and providers can benefit from the prudent use of RNAV procedures in the near-term, while laying the foundation for usage of more advanced CNS/ATM concepts, such as Required Navigation Performance (RNP) in the years to come. RNAV procedure implementation is desired by a large percentage stakeholders. Thus it is equally important that airspace planners and procedure developers design and implement RNAV procedures effectively and in a timely manner. This goal can be achieved by having access to the appropriate tools and data, as well, as a repeatable process. Potential benefits include: - Reduced flying times and fuel savings
- Decreased workload for controllers and pilots
- Reduction in air/ground communications
- Improved predictability and reliability
- Improved situational awareness for controllers and pilots
- Improved aircraft efficiency
Benefits of RNAV Terminal Procedures Prior to the implementation of RNAV routes, aircraft traveling to and from busy airports required aircraft to be vectored (that is, assigned to fly certain headings at specific altitudes and at specific speeds) in the airspace where routes are not currently defined. Since the current set of new procedures is based upon overlays of existing procedures, the RNAV route minimizes variances between desired versus actual flight paths and improves schedule predictability. With RNAV equipped aircraft, the number of controller clearances (voice communications) is reduced from approximately 8 to two or three. The same reduction holds for the pilots, and as a result, there is increased efficiency and reduced workload. In addition, because the route permits the aircraft to self-navigate all the way to touchdown, there are fewer altitude crossing restrictions and required speed assignments. The result is a more predictable flight path than the flight path variations that result from current pilot/controller practices. Aircraft not equipped with RNAV capabilities fly the conventional vectors.
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