Allowing aircraft to descend uninterrupted at low engine power, continuous descent operations promise to maximize fuel efficiency while minimizing environmental impact. Tailored arrivals is a concept for enabling continuous descents under constrained airspace conditions by integrating advanced air and ground automation through digital datalink. Operational trials were completed in January 2007 involving transpacific flights into San Francisco during early morning hours. Leveraging newly deployed Federal Aviation Administration automation in the oceanic environment, trajectory-based clearances were transmitted by datalink to Boeing 777 aircraft equipped with future air navigation system avionics. NASA's prototype ground-based automation for high-density arrival management tailored trajectory clearances to accommodate artificially imposed metering constraints. Upon sharing wind and descent-speed-intent data, ground-based and airborne automation were found to predict meter-fix arrival times to within a mean accuracy of 3 s over a 25 min prediction horizon. Corresponding mean altitude and alongtrack prediction errors of ground-based automation were 500 ft and 1:3 n mile, respectively, in comparison with surveillance truth. A benefits analysis suggests Boeing 777 fuel savings of between 200 and 3000 lb per flight (depending highly upon baseline traffic conditions) together with a corresponding reduction in CO 2 emissions of between 700 and 10,000 lb per flight.

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The Efficient Descent Advisor (EDA) is a prototype ground-based decision support tool (DST) that assists air traffic controllers in efficiently managing arrivals in en route airspace. Currently under development at NASA Ames Research Center, EDA is an extension of the Traffic Management Advisor (TMA) and a component of the Three Dimensional Path Arrival Management (3D PAM) project, a collaborative FAA/NASA/Industry effort. The objective of this study was twofold: one was to investigate the effects of fixed or dynamic turnout points as part of the path stretch maneuver on EDA operation performance and controller workload. The other was to examine the feasibility of the 3D PAM concept under the presence of uncertainty in aircraft weight, winds, and pilot maneuver conformance. Results indicate that the dynamic start-point configuration caused more corrective advisories to be issued, and made the traffic patterns more complex, though the configuration had little impact on controller workload. Results also demonstrated that the inclusion of uncertainties of the chosen magnitude did not significantly impact either EDA functions or usability for the traffic simulated.