Abstract
Continuous descent operations (CDO) is an efficient aircraft descent procedure that results in minimal fuel consumption because aircraft descend from their optimal top of descent (TOD) at idle engine thrust. So, it is desirable for all descending aircraft to follow CDO from the viewpoints of efficient aircraft operations and reduced environmental impact. Currently in Japan, CDO are implemented at three airports, but its operations are limited to time frames with low traffic volumes due to the difficulties air traffic control (ATC) experience in maintain required separation between aircraft during higher traffic situations especially at large-scale airports. The object of this study is to expand the implementation of CDO and increase the number of successful CDO at large-scale airports. First, we assumed the three underlying issues: uncertainty of predicted trajectories, capability of maintain separation minima, and controller workload. In order to deal with these issues, the following measures were conducted in this study. To address the uncertainty of predicted trajectories, we developed a trajectory generation algorithm with highly accurate trajectory prediction technology. In order to maintain the separation minima and for controller workload, we developed a CDO decision support tools for air traffic controllers. In the development of trajectory generation algorithm, the CDO descent trajectory was generated by numerical calculations using EUROCONTROL’s Base of Aircraft Data (BADA), and the validity of the model was confirmed by comparing it with a series of full flight simulator experiment data. We also considered constrained-CDO named as Fixed-FPA (Flight-path Angle) descent during which an aircraft descends continuously at a constant flight path angle. Results indicated that the fixed-FPA descent with speed control capability consumed less fuel compared to cancelled CDO. To validate the CDO decision support tool, a series of human-in-the-loop simulation experiments were implemented targeting the Kansai International Airport, which is the airport with highest number of CDO implementations in Japan.One of the results indicated the effectiveness of early speed adjustment during descent phase for maintain safety separation between CDO arrival aircraft. Experiments revealed that the effective number of arrival aircraft for such speed adjustment were three arrivals within a 10-minute time frame and seven arrivals in a 30-minute time frame.
