FIGURE 6.1 Elements of the center TRACON automation system (CTAS). Source: National Aeronautics and Space Administration.

  1. The traffic management advisor (TMA) supports the TRACON and en route traffic management controllers, primarily in developing an optimal plan, to assign each aircraft a scheduled time of arrival at a downstream point, like a final approach fix or runway threshold, and a sequence of arrival, relative to other aircraft approaching the terminal area. The traffic management advisor begins to compute these for inbound aircraft at a point about 200 miles or 45 minutes from the final approach. The plan is designed to optimize the overall flow of the set of aircraft, as well as the fuel consumption of each individual aircraft. At the same time, it accounts for various constraints on runway availability and aircraft maneuverability. The plan is also accompanied by an assessment of flight path changes to be implemented in order to accomplish the plan. A set of three displays assists the traffic management coordinator in evaluating the plan (Figure 6.2, see color plate). These include a time line of scheduled and estimated times of arrivals for the aircraft, a listing of alternative runway configurations, and a load graph, which indicates the anticipated traffic load across designated points in the airspace in 15-minute increments. The displays can be presented in large-screen formats for group viewing (Figure 6.3, see color plate). The actual implementation of the plan generated by the traffic management coordinator with the assistance of the traffic management advisor is carried out by the other two elements of CTAS, the descent advisor, and the final approach spacing tool.

  2. The descent advisor (DA) provides controllers at the final sector of the en



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