Integration of Traffic Flow Management Decisions

Abstract

The goal of traffic flow management in the national airspace system is to maintain efficient flow of air traffic without adversely impacting air traffic controllers' workload. It is shown in this paper that the air traffic service provider achieves this goal through a three-step process. In the first step, traffic flow management actions like Playbook and coded departure routes are used to reroute groups of aircraft flying in the same geographical neighborhood around flow- constrained areas. The rerouting process achieves the purpose of keeping traffic away from the flow- constrained areas but sometimes in the process creates congestion and bottlenecks in other regions of the airspace. To prevent this congestion, an additional layer of control is imposed on this traffic flow in the second step by temporal traffic decisions, such as miles-in-trail restrictions, which control the density of the flows along fixed paths. The aircraft comply with the miles-in-trail restriction by altering their speed, or by introducing a delay via flight path stretching or by airborne holding. In a third step, a few airborne aircraft may be locally rerouted around congested areas, while leaving other aircraft on their filed routes. The three-step hierarchical integration method is illustrated by an example that uses