Effects of UAS-Specific Capacity Constraints on Delays and Aircraft Encounters

This paper presents the impacts of Unmanned Aircraft System (UAS)-specific sector capacity constraints on the delay of UAS and the number of encounters between UAS and manned aircraft. The capacity constraints – represented by a limit placed on the number of aircraft allowed in a given sector – are satisfied by delaying the departure times of UAS that would otherwise exceed the constraint while preserving the intended routes of flights. A first-come first-served departure scheduler is used to determine departure times delays for UAS that satisfy the UAS-specific sector capacity constraints. In this paper, using both time-based and distance-based criteria for determining the aircraft encounters, the conflict risk for different UAS-specific capacity constraints is analyzed. Fast-time simulation results show that the number of encounters generally decreases as the UAS-specific sector capacity is reduced. When the capacity constraints are two times tighter, the number of encounters is reduced by up to 42%. The results also show a general trend toward increased departure delay for UAS as the capacity constraints get tighter.