Runway Assignments That Minimize Terminal Airspace and Airport Surface Emissions

Air traffic operations at and around major airports in the United States are in need of improvement. From the perspective of arrivals, when one or more runways are in great demand, unnecessary delay and emissions occur during peak periods at major airports while other runways at the same airport are operating under capacity. The primary cause of this imbalance in runway utilization is that traffic flow into and out of terminal areas is asymmetric (as a result of airline scheduling practices) and arrivals are typically assigned to the runway nearest the fix through which they enter the terminal area. From the perspective of departures, delays and emissions are incurred because arrivals take precedence over departures with regard to the utilization of runways (despite the absence of binding safety constraints) and because arrival trajectories often include level segments that ensure "procedural separation" from arriving traffic while planes are not allowed to climb unrestricted along the most direct path to their destination. This paper presents an optimization model for simultaneously assigning aircraft to runways and scheduling the arrival and departure operations on these runways such that the total emissions produced in the terminal area and on the airport surface are minimized. Model constraints include such real-world considerations as the minimum separation required between successive aircraft and the precedence relationships that aircraft flying a common route take. An analysis of simulation results indicates that implementation of this model could result in as much as a 30% reduction in arrival emissions with a corresponding 3% reduction in departure emissions.