Joel Klooster

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

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.

Flight validation of downlinked flight management system 4D trajectory

4-Dimensional (4D) trajectory-based operations (TBO) are viewed as a key enabler for future air operations by both SESAR1 and NextGen2. The European Commission project NUP 2+3 has created a unique infrastructure that provides the networking of real-time 4D Trajectory (4DT) data created by GE Aviations (formerly Smiths Aerospace) B737 flight management system (FMS) with air traffic management functions during revenue flights. This FMS has been modified to output and downlink an implementation of the ARINC 702A-1 Trajectory Bus, making the FMS-predicted 4DT available to controllers on the ground. This provision of the aircraft 4DT to the Air Navigation Service Provider (ANSP) has enabled a set of TBOs in Sweden including 4DT-based arrival management with time-based metering to the runway threshold, application of required time of arrival (RTA) to fine-tune this arrival management, and 4DT enabled advanced-continuous descent arrivals (A-CDA), referred to as green approaches by the project. The NUP2+ project goals include facilitating the study of 4DT performance requirements, associated 4DT air/ground networking requirements and producing operational flight data to support further studies. To begin to produce such study data, a series of controlled Trajectory Evaluation Flights was conducted by the NUP2+ project in December 2006. This paper presents an overview of the motivation, objectives, experiment conduct, and preliminary data analysis of this initial set of flights. Plans for the projects expansion of these experiments are also discussed.

Trajectory synchronization and negotiation in Trajectory Based Operations

Trajectory Based Operations (TBO) is a key component of both the US Next Generation Air Transport System (NextGen) and Europes Single European Sky ATM Research (SESAR). There is a significant amount of effort underway in both programs to advance this concept. Trajectory Synchronization and Negotiation are key required capabilities in both the NextGen and SESAR TBO concepts, and they provide the framework to improve the efficiency of airspace operations. In recognition of the importance of TBO, General Electric and Lockheed Martin have created a Joint Strategic Research Initiative (JSRI), which aims to generate technologies that accelerate adoption of TBO. This paper explores various trajectory synchronization and negotiation concepts, including existing gaps and shortfalls. This paper also presents the JSRI simulation and evaluation environment being developed, which embeds trajectory synchronization and negotiation concepts, and has the potential to address existing gaps and shortfalls.

Practice Summary: Flight Trajectory Optimization

We developed and implemented a novel algorithm to control the trajectory of an aircraft flight to reduce the costs it incurs. Our algorithm computes the values for the parameters to be entered into the aircrafts flight management system to minimize the fuel and schedule-adherence costs incurred on the flight. We implemented it in a prototype software system that is currently in use at GE Aviation Services.