Required time of arrival as a control mechanism to mitigate uncertainty in arrival traffic demand management

摘要

The objective of this study is to explore the use of Required Time of Arrival (RTA) capability on the flight deck as a control mechanism on arrival traffic management to improve traffic delivery accuracy by mitigating the effect of traffic demand uncertainty. The uncertainties are caused by various factors, such as departure error due to the difference between scheduled departure and the actual take-off time. A simulation study was conducted using the Multi Aircraft Control System (MACS) software, a comprehensive research platform developed in the Airspace Operations Laboratory (AOL) at NASA Ames Research Center. The Crossing Time (CT) performance (i.e. the difference between target crossing time and actual crossing time) of the RTA for uncertainty mitigation during cruise phase was evaluated under the influence of varying two main factors: wind severity (heavy wind vs. mild wind), and wind error (1 hour, 2 hours, and 5 hours wind forecast errors). To examine the CT performance improvement made by the RTA, the comparison to the CT of the aircraft that were not assigned with RTA (Non-RTA) under the influence of the selected factors was also made. The Newark Liberty International Airport (EWR) was chosen for this study. A total 66 inbound traffic to the EWR (34 of them were airborne when the simulation was initiated, 32 were pre-departures at that time) was simulated, where the pre-scripted departure error was assigned to each pre-departure (61 % conform to their Expected Departure Clearance Time, which is +/-300 seconds of their scheduled departure time). The results of the study show that the delivery accuracy improvement can be achieved by assigning RTA, regardless of the influence of the selected two factors (the wind severity and the wind information inaccuracy). Across all wind variances, 66.9% (265 out of 396) of the CT performance of the RTA assigned aircraft was within +/- 60 seconds (i.e. target tolerance range) and 88.9% (352 out of 396) aircraft met +/-300 seconds marginal tolerance range, while only 33.6% (133 out of 396) of the Non-RTA assigned aircraft's CT performance achieved the target tolerance range and 75.5% (299 out of 396) stayed within the marginal. Examination of the impact of different error sources - i.e. departure error, wind severity, and wind error - suggest that although large departure errors can significantly impact the CT performance, the impacts of wind severity and errors were modest relative the targeted +/- 60 second conformance range.