An Airspace Concept Evaluation System Characterization of National Airspace System Delay

Abstract

This paper presents an analysis of National Airspace System (NAS) delay. An interacting set of models called the Airspace Concept Evaluation System (ACES) was used to simulate one day of NAS-wide air tra‐c. A total of 36 simulations were run. They included nine difierent airport capacity conditions across the NAS and four levels of NAS-wide demand. The analysis of delay results for these 36 simulations shows that delay increases quadratically with increased demand. The delay versus capacity curves have linear trends. However, nonlinearities within these curves expand with increased demand. These nonlinearities suggest that additional factors such as regional concentrations of airports in low capacity conditions due to regional weather do have a signiflcant in∞uence on the results. This analysis is an important flrst step in exploring and understanding the intricacies of the NAS so that further efiorts can be made to improve it. I. Introduction Over the past several decades, the demand for air travel has increased. The National Airspace System (NAS) has evolved with modest advances in weather/wind prediction, faster and quieter airplanes, and by adding new runways and technologies at airports. Each small step plays a part in the attempt to minimize delay as demand continues to grow. However, current technology is fast approaching the point of diminishing returns. New airspace operational concepts will be necessary to reverse this imbalance. These conceptual changes may afiect the entire NAS in unpredictable ways. The Airspace Concept Evaluation System (ACES) is a NAS-wide fast-time simulation developed at NASA Ames Research Center. ACES simulates a model of the NAS with interacting agents for center control, terminal ∞ow management, airports, individual ∞ights, and other NAS elements. These agents pass messages between one another similar to real world communications. This distributed agent based system is designed to emulate the highly unpredictable nature of the NAS, making it a suitable tool to evaluate envisioned airspace concepts. Before new concepts can be evaluated, the tool must be used to evaluate the current NAS situation. This will lead to the development of processes that attempt to better understand the interdependencies between elements making up the NAS. Through these processes, the cascading efiects that interdependencies produce on the system can be better understood. As a flrst step, this study was performed to establish an initial characterization of NAS-wide delay. The goal was to use ACES to simulate a variety of demand and capacity scenarios in the NAS to quantitatively establish their efiects on system-wide delay. The study included thirty-six simulations, each encompassing a 24-hour demand period. The simulations varied in ∞ight demand and airport operational capacity. Four ∞ight demand cases were studied which included a representation of current-day 2002, an approximate doubling of current-day 2002, and two intermediate ∞ight demand schedules. All cases included domestic commercial passenger ∞ights operating between the top 98 US airports. Capacity was varied with nine cases representing difierent airport operational capacities. Two cases represented optimum and worst-case airport states. All airports operated under visual ∞ight rules (VFR) during the simulation period for the optimum case. For the worst case, the 30 benchmark airports 8 operated