Mitigating the Effect of Demand Uncertainty Due to Departures in a National Time-Based Metering System

Demand uncertainty, as manifest by the difference between expected and actual departure times, is a significant source of error f or predicting times-of-arrival for aircraft at points of congestion such as airports. Assigning a nd controlling four-dimensional trajectories is envisioned as an important component of the U.S. next generation air traffic system, with the ability to schedule aircraft and a ssign delays based on predicted arrival times an important component of such four-dimensional trajectory capability. For this reason methods need to be developed to mitigate the effects of demand uncertainty on predicted times-of-arrival. This paper discusses t he results of ongoing research into determining appropriate and manageable methods for mitigating such effects on a scheduling system. The results follow previous stu dies that examined the effect of demand uncertainty on scheduling over short distances (app roximately 250 nautical miles); this study found that different methods may be needed for long distances. While no conclusive results were found, a method for identifying and testing po ssible solutions is presented along with the results of the analysis to date.