Three-Degree Decelerating Approaches in Arrival Streams Arjen de Leege, M.Sc. TU-Delft – Faculty of Aerospace Engineering Delft University of Technology – Erasmus University Rotterdam University.
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Three-Degree Decelerating Approaches in Arrival Streams Arjen de Leege, M.Sc. TU-Delft – Faculty of Aerospace Engineering Delft University of Technology – Erasmus University Rotterdam University of Twente – Radboud University Nijmegen University of Groningen – Eindhoven University of Technology Environmental impact & fuel burn • Aircraft noise and emissions are becoming limiting factors for the growth of aviation • Airlines focus on fuel-efficiency TRAIL Congress 2008 www.rstrail.nl Continuous Descent Approach • The CDA is a cost effective mean to reduce the environmental impact and fuel burn during approach Altitude Top of Descent TRAIL Congress 2008 Area of noise benefit Along Track Distance • No level segments, vertical profile higher • Lower engine thrust, mostly idle thrust www.rstrail.nl Runway CDAs & Runway Capacity Distance to the Runway • Runway capacity problems limit the use of CDAs TRAIL Congress 2008 separation ? CDA Step-wise Time ΔT ΔT CDA • Deceleration is a function of aircraft performance, weather, and the pilot • ATCos apply larger separation buffers to ensure separation 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 TRAIL Congress 2008 www.rstrail.nl • This information is more readily available in the cockpit rather than on the ground Self-Spacing Concepts Distance-Based AC2 manages separation between AC2 and AC3 Altitude AC1 AC2 AC3 AC1 manages separation between AC1 and AC2 Along Track Distance Time-Based AC1 Altitude TRAIL Congress 2008 Estimated = Required AC2 AC3 Along Track Distance www.rstrail.nl TDDA Trajectory Intercept 30 flight path to RWY Altitude Normal Approach TCB Altitude Along Track Distance Reference Altitude IAS TRAIL Congress 2008 VAPP Along Track Distance www.rstrail.nl November 2, 2015 TDDA Goals Separation Goal Altitude Min Sep. = Min Safe Sep. Along Track Distance IAS TRAIL Congress 2008 V = Vref Along Track Distance www.rstrail.nl November 2, 2015 8 TDDA Control Space Continued IAS - Altitude Distance - Time 0 260 50 240 IAS [kts] Time [s] 100 150 200 250 160 20 15 10 Distance to THR [nm] www.rstrail.nl 200 180 TRAIL 300 Congress 2008 350 400 25 220 5 0 140 7000 6000 5000 4000 3000 2000 1000 Altitude [ft] November 2, 2015 0 Initial Separation (1) TRAIL Congress 2008 Distance to THR [nm] 30 Initial Separation: 112 - 138s or 8.3 - 10nm Lead Trajectory Separation Boundary Own Slow Trajectory Own Fast Trajectory 25 20 15 10 5 0 0 100 200 300 400 500 Time [s] www.rstrail.nl November 2, 2015 Initial Separation (2) 0 Lead Trajectory Separation Boundary Control Space Boundary 50 100 Time [s] 150 200 250 300 TRAIL Congress 2008 350 400 450 25 20 15 10 5 0 Distance to THR [nm] www.rstrail.nl November 2, 2015 Simulate Arrival Streams of Aircraft Flying the TDDA • Fast time TDDA simulation tool • Distance-based and time-based self-spacing • Simulate arrival streams of 8 aircraft TRAIL Congress 2008 www.rstrail.nl • 5 aircraft types, different mass, pilot response delays, and actual wind conditions • Aircraft initially positioned the middle of their control space November 2, 2015 Runway Capacity TRAIL Congress 2008 55 55 50 50 45 45 40 40 35 35 30 30 25 25 400 300 200 100 0 Arrival Streams Self-Spacing www.rstrail.nl Time-Based Distance-Based Mean 35.7 39.2 Capacity [AC/H] Capacity [AC/H] Self-Spacing Distance-Based Time-Based 100 200 300 400 Arrival streams Descriptive Median Std. 35.3 3.3 38.8 3.6 [AC/H] Min Max Range 13 26.7 49.7 23.0 30.9November 53.3 2,22.3 2015 Runway Capacity • • • Comparison with conventional approach procedure required Simulation of conventional procedure not available Make estimate using ‘packing factor’ PF TRAIL Congress 2008 www.rstrail.nl • • • k i2 k i2 S allow ed S actual S actual S allowed Theoretical maximum PF = 1 Distance-based: PF = 0.90 Time-based: PF = 0.81 November 2, 2015 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 TRAIL Congress 2008 • 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 www.rstrail.nl Three-Degree Decelerating Approaches in Arrival Streams Arjen de Leege, M.Sc. TU-Delft – Faculty of Aerospace Engineering Delft University of Technology – Erasmus University Rotterdam University of Twente – Radboud University Nijmegen University of Groningen – Eindhoven University of Technology TRAIL Congress 2008 www.rstrail.nl TRAIL Congress 2008 www.rstrail.nl Altitude TDDA Scheduling & Optimization TCB Altitude Opt. for separation and noise Optimization of Flap Schedule for separation and noise TRAIL Congress 2008 IAS Along Track Distance TCB Altitude Opt. to Meet Goals Optimization of Flap Schedule for separation and noise Along Track Distance www.rstrail.nl November 2, 2015