1 Ninth USA/Europe Air Traffic Management Research and Development Seminar (ATM2011) Estimating ATM Efficiency Pools in the Descent Phase of Flight Potential Savings in both Time and Fuel

Abstract — In the descent phase of flight, limited research has focused on the benefits of ATM improvements in an environment where flight times are constrained by capacity. Both NextGen and SESAR have prioritized increasing capacity to reduce congestion and absorb future demand. For the foreseeable future, ATM will always have to manage congestion. This paper focuses on a methodology for estimating the total benefit pools, in terms of time and fuel that ATM can potentially influence in the descent phase of flight. Best practices from existing research on efficiency pools are incorporated and refined to provide estimates with data commonly available in today’s ATC system. The analysis shows that at busy airports, most of the additional fuel used on top of an unconstrained trajectory is directly related to the need to sequence aircraft. How to absorb time in a time constrained environment in the most efficient manner is a key issue. This paper explores the benefits of reducing speed in cruise to absorb delays currently managed in the terminal area. The findings estimate the unimpeded benefit pool, actionable by ATC in the terminal area, averages 3 minutes for the top 34 airports in both US and Europe, or approximately 100 kg. of additional fuel per arrival. The potential benefit of reducing speed in cruise (i.e. with no change in capacity) is estimated to be around 30 percent of the unconstrained benefit pool in a conservative scenario. These findings provide incentive for further research complementing the numerous studies related to optimal descent profiles, which are mainly associated with non-congested periods. The estimated benefit pool associated with speed control in this paper applies directly to optimizing congested periods. Keywords-component; ATM Benefit Pools, fuel savings, speed control, delay methodology I