DESIGN AND DEVELOPMENT OF THE EN ROUTE DESCENT ADVISOR (EDA) 
FOR CONFLICT-FREE ARRIVAL METERING

Richard A. Coppenbarger, Richard Lanier, Doug Sweet, and Susan Dorsky


ABSTRACT

This paper describes the fundamental design and development of a 
new decision-support tool for time-based arrival metering, referred 
to as the En Route Descent Advisor (EDA). This automation is being 
developed at NASA Ames Research Center as a component of the 
Center-TRACON Automation System (CTAS). EDA computes advisories for 
the air-traffic controller to help deliver aircraft to an 
arrival-metering fix in conformance with a scheduled time-of-arrival 
constraint, while preventing separation conflicts with other aircraft 
along the arrival trajectory. The CTAS Traffic Management Advisor (TMA), 
fielded at numerous facilities in the United States under the FAA 
Free Flight Phase 1 initiative, computes the scheduled arrival times 
at the metering fix that EDA targets for optimal throughput into the 
terminal airspace. By computing strategic maneuver advisories based 
on speed, altitude, and heading to meet arrival time with a high 
degree of precision, EDA has the potential to significantly extend 
the capacity, efficiency, and workload benefits already attributed 
to TMA operations. The paper first describes the underlying trajectory 
process, followed by a description of the core meet-time and conflict 
resolution algorithms employed by EDA. The key aspects of the user 
interface are then described, which allow controllers to receive, 
evaluate, and accept EDA advisories at their discretion. Finally, a 
closed-loop simulation system for evaluating EDA in the laboratory is 
described, along with key findings obtained during a series of 
preliminary controller-in-the-loop simulation experiments.