Flight trials: "runway-to-runway" required time of arrival evaluations for time-based ATM environment

Abstract

Flight trials were conducted by Smiths Aerospace with Scandinavian Airlines in the spring of 200 1 evaluating the use of the Four-Dimensional Flight Management System (4-D FMS) and it's Required-Time-of-Arrival (RTA) function for a future Air Traffic Management (ATM) environment. 4-D FMS, along with air-ground datalink capability, is central to the ATM operational environment established by the European Commission's AFAS (Aircraft in the -Future ATM Bstem) program. These RTA trials supported this project's development by assessing the current generation FMS RTA algorithm's performance in an AFAS-like flight environment, and identifying necessary improvements for the next generation avionics. The Swedish CAA participated in these trials by providing priority servicing to the trials' flights allowing the evaluation of 4-D FMS performance in an "undisturbed AFAS operational scenario". Required-Time-of-Arrival (RTA) points were established at takeoff targeted for waypoints as late in the flight plan as the top of the Standard Terminal Arrival (STAR) and the destination runway threshold. The Smiths Aerospace standard FMS equipment on the Boeing "Next Generation" B737 was then responsible to guide the aircraft for the entire flight while an observer in the jump seat recorded performance data. The preliminary results from the 33 trial flights and subsequent analysis indicate that aircraft equipped with the current generation Smiths FMS can reliably predict and maintain a 4-D trajectory over an entire flight in -real-world fleet operations. Time-of-arrival errors at waypoints located at the top of the Standard Arrival procedures were demonstrated to be less than 7 seconds with a standard deviation of 4.8 seconds. In cases targeting the runway with an RTA constraint, errors were bounded to 21 seconds with a standard deviation of 12.7 seconds. This precise "runway-torunway" trajectory prediction and control capability is a critical building block in the AFAS "gate-togate" 4-D ATM concept. This paper describes the background and setup of these trials. Five supporting research objectives are introduced including RTA accuracy assessment, wind modeling effects, and the evaluation of trajectory time-control authority. Preliminary results and analysis are presented. Final analysis results will follow in a subsequent paper. Figure 1: SAS B737-600 Aircraft 0-7803-7034-

Study of the required time of arrival function of current FMS in an ATM context

“…The RTA will only trigger control activity if the ETA differs from the RTA by more than a certain tolerance. On some aircraft types, this tolerance is configurable, and typically narrows as the aircraft gets closer to the RTA waypoint [3]. The RTA target speed, as well as the possible speed variations within operational limits are displayed on the speed tape of the Primary Flight Display (PFD).…”

Flight validation of downlinked flight management system 4D trajectory

“…the planned location of the aircraft in space and time. This is a change from the present 'clearance-based control' dependent on observation of the aircraft current state, to trajectory-based control, with the goal of allowing the aircraft to fly along the user-preferred 4 trajectory. This concept is fundamental to several NextGen Operational Improvements, such as:…”

“…This trajectory then forms the basis for traffic flow management, deconfliction with other aircraft trajectories, and other system services. Through this exchange of aircraft trajectories, today's first-come, first-served ATC system will be replaced by a system comprising 4 User "preferred" in the sense of optimized to operator economical criteria 1-4244-1108-4/07/$25.00 ©2007 IEEE.…”

“…In 2001, Smiths Aerospace (now GE Aviation) conducted a series of flight trials with Scandinavian Airlines (SAS) evaluating the use of their FourDimensional Flight Management System (4-D FMS) and its Required-Time-of-Arrival (RTA) function for a future Air Traffic Management (ATM) environment [4,5]. The results from the 33 trial flights and subsequent analysis indicated that aircraft equipped with the current generation Smiths FMS 5 can reliably predict and maintain a 4-D trajectory over an entire flight in real-world fleet operations.…”

Simulation Results for Airborne Precision Spacing along Continuous Descent Arrivals

“…This additional space decreases the overall capacity of the destination airport. To maintain the arrival rates required for a very busy airport, different terminal area concepts have been researched over the past 30 years, to include time-based, [1][2][3][4] vectors and speed commands from a ground system, 5 Required Time of Arrival procedures for CDAs, 6,7 and speed commands generated on-board the aircraft. [11][12][13][14][15][16] Required Time of Arrival concepts are being developed to support high throughput for CDA procedures.…”