4D Trajectory and Time-of-Arrival Control to Enable Continuous Descent Arrivals

Abstract

Aircraft noise and emissions are quickly becom ing constraining factors to increasing the capacity of terminal airspace in both Europe and North America . Trajectory Based Operations are proposed as a key means to increase airspace capacity, while Continuous Descent Arrivals have been shown to decrea se the environmental impact of aviation. The European Commission supported project NUP2+ has created a unique infrastructure to network the 4 Dimensional Trajectory generated by an advanced Flight Management System with Air Traffic Control in revenue service flights. The use of this 4DT c ombi ned with time -based metering at the runway threshold has enabled Scandinavian Airline Systems to fly CDA s into Stockholm -Arlanda International Airport. This paper describes a set of dedicated trajecto ry evaluation flight trials that occurred in Sweden in September 2007. The procedure setup and research objectives are described. Results and analysis of the time -control and trajectory stability are presented indicat ing that the current generation avion ics can reliably predict and control to a precise 4D trajectory, with time -of -arrival errors at the destination runway less than 15 seconds . The impact of forecast wind accuracy on the time -control is examined, showing the importance of accurate wind fore casts. Comparison of the trajectory accuracy and stability during various stages of the flight both with and without time -control is presented along with a lternative methods of 4D TBO combined with time -control. Finally, assessment of the trajectory file size and dynamics indicate an average link load of only1.5kb/60s is needed. Conclusions and recommendations for expansion of these types of TBO as well as modifications for the next generation avionics are also presented.