Continuous Descent Arrival National Operational Feasibility

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Continuous Descent Arrival, also called Continuous Decent Approach, is a procedure where aircraft descend directly from a relatively high altitude without the traditional leveling off in a series of steps. Recent CDA (see PARTNER Project 4, Continuous Descent Arrival) ) studies focused on CDA’s potential fuel/flight time saving and noise/emission reduction. Several studies examined the excess fuel from level-offs for arrivals at large U.S. airports. In these studies, safety (such as separations between aircraft) was not the primary concern. However, if CDA should be employed in the practical system, it is critical to investigate its operational feasibility for heavy traffic scenarios. The objective of this research is therefore to examine and quantify the operational feasibility of CDAs nationally. We examine a number of large airports in the U.S. and estimate the number or percentage of arrivals that could reasonably be expected to perform a CDA, or part of a CDA, given airspace and air traffic flow control constraints. This research will help the FAA quantify CDA’s potential fuel savings and economic benefits. In this research, our primary simulation tool is the Future ATM Concepts Evaluation Tool, software under development at NASA Ames Research Center.


A set of software tools were developed for studies on feasibility of continuous descent arrivals under normal and heavy air traffic. These tools were based on the NASA-developed software Future ATM Concepts Evaluation Tool (FACET) as well as Matlab statistic toolboxes.

Participating university

Purdue University

Lead investigators

Dengfeng Sun, Assistant Professor, School of Aeronautics and Astronautics Engineering, Purdue University,

FAA program manager

Joseph Post,


Evaluation of Continuous Descent Approach in Normal Air Traffic Conditions. Project 40 final report. Download