Future Air Ground Integration - FAGI

1. FAGI – Future Air Ground IntegrationAlexander Kuenz,Institute of Flight Guidance, DLR Braunschweig, GermanyPresented on REACT Workshop 2008, Seville

2. Future Air Ground Integration - FAGI • DLR-funded project • Duration Jan 2007 – Dec 2009 • Involved Departments: • Institute of Flight Guidance/Braunschweig • Institute of Communication and Navigation/ Oberpfaffenhofen+Neustrelitz • Equipment: Flight Operations/Braunschweig and Institute of Flight Systems/Braunschweig • First concept finalized, first validation by experts done • Development of tools in progress • Final validation by ATM-simulations in 2009

3. Motivation: A Definition of „Green Trajectories“ Environmentally friendly procedures in terms of • NOx and CO2 emissions • Noise emissions andimmisions on the ground • Fuel efficiency Achieved by • Efficient usage of engines • Low drag aircraft configuration • Flying high altitudes } Arrival: Continuous Descent Approaches (CDA)

4. DLR`s Advanced Continuous Descent Approach CFL Engines idle No level flight from Top of descent to touchdown Altitude • …but great demands on • trajectory prediction and • guidance precision Once in descent, it is hardly possible to react on ATC instructions 3° Distance to Touchdown

5. Trajectory Prediction and Guidance using DLR’s Advanced Flight Management System (AFMS)

6. Flight and Simulation TrialsVFW614 (ATTAS) Airbus A330 FFS (ZFB) Adaptation to aircraft type via Base of Aircraft Data provided by Eurocontrol

7. Deviations from planned 4D-trajectory Deviations may occur due to • Insufficient or imprecise aircraft performance data • Jitter in the configuration points • Inaccurate weather forecast • … Possible reactions are to • Hold the correct speed and cumulate an altitude error • Hold the correct altitude and cumulate a speed error • Average altitude and speed error The AFMS tries to hold the time deviation at minimum.

8. Results of automatic and manual ATTAS/A330 approaches (>30 NM) Two approaches differed (10 seconds time precision): • Constant downdraft in the lee of Harz mountains, but the weather forecast does not contain vertical wind components • A mini jet stream was encountered between 10000ft and 5000ft without a sampling point for the weather grid in-between. Inaccurate weather is the main factor for deviations!

9. GED 10 8 6 4 REDGO (FAF) 2 ACDA LDLP 0 RW25R 0 2 4 6 8 10 12 14 16 NM Noise footprints of LDLP and ACDA (SIMUL)Approaches with Airbus A320 to 25R in Frankfurt Main via Gedern NM

10. Two Aircraft landing in Frankfurt… Capacity Driven Early Merging: • Same Lateral Route • Same Altitude Profile • Same Speed Profile  Assuming different types of aircraft, ACDAs are unsuitable in high traffic situations

11. Requirements to handle green trajectories in high traffic TMAs: • Trajectory-based handling to benefit from the described airborne capabilities  User preferred Trajectory • Mixed traffic support for FMS-equipped and unequipped aircraft • Late merging to fly the aircraft’s optimum profile as long as possible • Time-based separation could even improve today’s capacity • Emergency handling and flexible planning for short term departures

12. DLR’s approach for a Trajectory Based TMAhandling Extended TMA • Radius 80-120NM to allow time variation by speed changes • Strategic path stretching if speed variation is insufficient

13. Late Merging Point • Merging just before final approach (e.g. G/S intercept) • Time based merging, time constraint for every approaching aircraft DLR’s approach for a Trajectory Based TMAhandling

14. RTAs for the Late Merging Point are assigned when entering the E-TMA DLR’s approach for a Trajectory Based TMAhandling

15. Static E-TMA entries • Aligned to the main traffic routes • Keep TMA structured and clearly arranged DLR’s approach for a Trajectory Based TMAhandling

16. Dynamic E-TMA entries • Are provided if possible • For aircraft entering between static entries DLR’s approach for a Trajectory Based TMAhandling

17. Procedural Separation before merging allows flying aircraft optimized vertical and speed profiles DLR’s approach for a Trajectory Based TMAhandling

18. FMS-equipped aircraft can fly their predicted trajectory on their own and fulfill the time constraint at the Late Merging Point 10:05:37 +/-5s DLR’s approach for a Trajectory Based TMAhandling

19. Unequipped aircraft are supposed to be integrated by means of a ground based guidance module. A trombone path stretching area helps to improve accuracy. 10:07:20 +/-?s DLR’s approach for a Trajectory Based TMAhandling

20. Trombone also used for • Insertion of short term departures • Equipped aircraft violating their constraints • Insertion of emergency delays DLR’s approach for a Trajectory Based TMAhandling

21. DLR’s approach for a Trajectory Based TMA handling Procedural separation between direct and trombone aircraft: • Equipped aircraft perform shallow descents • Trombone aircraft are forced to stay above at intersections The proposed E-TMA structure is promising but not verified yet!

22. TP Air-Ground Synchronization: Requirements Onboard: • Highly accurate 4D trajectory flyable fulfilling predefined constraints • High Mid-term reliability, no update necessary in most cases for last 100NM On Ground: • 4D trajectory needed • for Trajectory Based Conflict Detection and Resolution • for Conformance Monitoring • Required lateral and time accuracy is medium to high • Required vertical accuracy is low due to route structure

23. TP Air-Ground Synchronization: Prediction • No need for a high bandwidth data link • Air and Ground Trajectory predicted with preferably same input data • List of Waypoints exchanged by Route Name via R/T • Constraints are defined by Route + one Time constraint at Late-Merging Point • Aircraft Performance Model from BADA • Descent Parameter via R/T • Some inputs not available on ground: Same Weather, Aircraft’s Weight, Turn Radius, Airliner’s specific settings…

24. TP Air-Ground Synchronization: Assumptions Lateral assumptions: • Route based on straights and curved segments • Bank-Angle: Speed & Bank  Turn-Radius Vertical assumptions: • Arriving aircraft do not climb in E-TMA • Aircraft descend as late as possible flying the descent profile Speed assumptions: • Arriving aircraft do not accelerate in E-TMA • Arriving aircraft decelerate as late as possible to reach RTA at LMP Learn from aircraft’s progress: when deviations occur, regenerate!

25. Conclusion • ACDA flight and simulation trials with ATTAS & A330 proved high accuracy of DLR’s AFMS in manual and automatic mode • Inaccurate weather forecast is main factor for deviations • Achieved precisions of 150ft altitude and 5 seconds time deviation for idle descents are good enough for trajectory based TMA-handling • A trajectory based TMAconcept was introducedproviding operationsfor mixed traffic and emergencies • No need for a high band-width data link, TP synchron-ization can be done viaR/T.

26. Thanks for your attention! Questions?