1. Delft University of Technology – Erasmus University Rotterdam University of Twente – Radboud University Nijmegen University of Groningen – Eindhoven University of Technology Three-Degree Decelerating Approaches in Arrival Streams Arjen de Leege, M.Sc. TU-Delft – Faculty of Aerospace Engineering

2. TRAIL Congress 2008 www.rstrail.nl Environmental impact & fuel burn Aircraft noise and emissions are becoming limiting factors for the growth of aviation Airlines focus on fuel-efficiency

3. TRAIL Congress 2008 www.rstrail.nl Along Track Distance Altitude Top of Descent Runway CDA Area of noise benefit No level segments, vertical profile higher Lower engine thrust, mostly idle thrust Continuous Descent Approach The CDA is a cost effective mean to reduce the environmental impact and fuel burn during approach

4. TRAIL Congress 2008 www.rstrail.nl CDAs & Runway Capacity Time Distance to the Runway ΔTΔT ΔT CDA separation Step-wise CDA ? Deceleration is a function of aircraft performance, weather, and the pilot ATCos apply larger separation buffers to ensure separation Runway capacity problems limit the use of CDAs

5. TRAIL Congress 2008 www.rstrail.nl Self-Spacing A possible solution for the runway capacity problem Transfer of the spacing task from the ATCo to the pilot Maneuverability during a CDA is driven by aircraft performance, weather, and pilot control strategy This information is more readily available in the cockpit rather than on the ground

6. TRAIL Congress 2008 www.rstrail.nl Self-Spacing Concepts AC1 AC2 AC3 AC1 manages separation between AC1 and AC2 AC2 manages separation between AC2 and AC3 Along Track Distance Altitude Distance-Based AC1 AC2 AC3 Along Track Distance Altitude Time-Based Estimated = Required

7. TRAIL Congress 2008 www.rstrail.nl TDDA Trajectory May 21, 2015 Along Track Distance IAS Altitude Idle Thrust TCB Altitude V APP Reference Altitude Normal Approach Deceleration Flap & Gear Extension Intercept 3 0 flight path to RWY

8. TRAIL Congress 2008 www.rstrail.nl TDDA Goals May 21, 2015 8 Along Track Distance IAS Altitude Separation Goal Min Sep. = Min Safe Sep. V = Vref

9. TRAIL Congress 2008 www.rstrail.nl TDDA Control Space Continued May 21, 2015 0510152025 0 50 100 150 200 250 300 350 400 Distance to THR [nm] Time [s] 01000200030004000500060007000 140 160 180 200 220 240 260 Altitude [ft] IAS [kts] IAS - AltitudeDistance - Time

10. TRAIL Congress 2008 www.rstrail.nl Initial Separation (1) May 21, 2015 0100200300400500 0 5 10 15 20 25 30 Time [s] Distance to THR [nm] Initial Separation: 112 - 138s or 8.3 - 10nm Lead Trajectory Separation Boundary Own Slow Trajectory Own Fast Trajectory

11. TRAIL Congress 2008 www.rstrail.nl Initial Separation (2) May 21, 2015 0510152025 0 50 100 150 200 250 300 350 400 450 Distance to THR [nm] Time [s] Lead Trajectory Control Space Boundary Separation Boundary

12. TRAIL Congress 2008 www.rstrail.nl Simulate Arrival Streams of Aircraft Flying the TDDA May 21, 2015 Fast time TDDA simulation tool Distance-based and time-based self-spacing Simulate arrival streams of 8 aircraft 5 aircraft types, different mass, pilot response delays, and actual wind conditions Aircraft initially positioned the middle of their control space

13. TRAIL Congress 2008 www.rstrail.nl Runway Capacity May 21, 2015 13 Self-SpacingDescriptive [AC/H] MeanMedianStd.MinMaxRange Time-Based35.735.33.326.749.723.0 Distance-Based39.238.83.630.953.322.3

14. TRAIL Congress 2008 www.rstrail.nl Runway Capacity May 21, 2015 Comparison with conventional approach procedure required Simulation of conventional procedure not available Make estimate using ‘packing factor’ Theoretical maximum PF = 1 Distance-based: PF = 0.90 Time-based: PF = 0.81

15. TRAIL Congress 2008 www.rstrail.nl Conclusions Runway capacity problems limit the use of CDAs Transfer of spacing task from the ATCo to the pilot is a possible solution The TDDA is a CDA that gives the pilot control over the descent path to perform the spacing task Initial separation is crucial for aircraft to be able to fly a CDA in an arrival stream Fast-time simulations showed that the runway capacity is sustained when flying the TDDAs in a distance-based self-spacing environment

16. Delft University of Technology – Erasmus University Rotterdam University of Twente – Radboud University Nijmegen University of Groningen – Eindhoven University of Technology Three-Degree Decelerating Approaches in Arrival Streams Arjen de Leege, M.Sc. TU-Delft – Faculty of Aerospace Engineering

17. TRAIL Congress 2008 www.rstrail.nl

18. TRAIL Congress 2008 www.rstrail.nl

19. TRAIL Congress 2008 www.rstrail.nl TDDA Scheduling & Optimization May 21, 2015 Along Track Distance IAS Altitude Optimization of Flap Schedule for separation and noise TCB Altitude Opt. for separation and noise TCB Altitude Opt. to Meet Goals