Optimizing Flight Paths for RNP Aircraft in Busy Terminal Areas - First Step Towards 4-D Navigation

The next generation air transportation system (NGATS) concepts, defined by the Joint Planning and Development Office (JPDO), consider 4D navigation as one of the core elements. During intervals of heavy traffic, establishing and achieving 4D operations for arrivals in busy terminal areas will be a major challenge. This paper presents the development and demonstration of a decision support tool called logical expansion of arrivals and departures to enhance RNP (required navigation performance) (LEADER). This human-in-the-loop simulation tool (with controller, pilot and traffic management coordinator (TMC) workstations) permits each aircraft, based on its capabilities, to fly desired 3D flight paths (shortest flight paths with continuous descent) under varying wind conditions. A flexible terminal area route structure is developed that eliminates all traffic merge points prior to the traffic converging on to the final approaches. The design of the tool is based on minimizing the variations between the aircraft flight planning and actual operations by defining routes all the way to touchdown and establishing landing schedules using accurate flight time estimates and pair-wise wake vortex separations. Traffic under high density conditions at a major airport during instrument meteorological conditions (IMC) was simulated. The results show significant savings in distance traveled and flight times, as well as a reduction in air/ground communications that would provide reduced operating costs for the users and lower workload for the operators. On an average, the flights saved 10.94 nmi in distance flown, 2 minutes and 16 seconds in flying time and reduced air/ground communications by 30 percent. Since the terminal areas involve most complex traffic patterns due to continuously climbing and descending flights, the tool offers a foundation and a first step towards realizing the future goal of using 4D navigation from end to end in the entire National Airspace System (NAS)