Airborne Separation and Self-Separation within the Distributed Air/Ground Traffic Management Concept

1. ASAS Thematic Network - Workshop 2 Malmö, Sweden October 6-8, 2003 Airborne Separation and Self-Separation within theDistributed Air/Ground Traffic Management Concept                Mark G. Ballin NASA Langley Research Center

2. Presentation Overview • Introduction to DAG-TM Airborne Component • Potential for Benefits • En Route Free Maneuvering Operations • Capacity-Constrained Terminal Arrival Operations • Closing Remarks

3. FlightCrew • Information • Decision making • Responsibility AeronauticalOperationalControl Air Traffic ServiceProvider Distributed Air/Ground Traffic Management (“DAG-TM”) Concept Premise: Large improvements in system capacity, airspace user flexibility, and user efficiency will be enabled through • Sharing information related to flight intent, traffic, and the airspace environment • Collaborative decision making among all involved system participants • Distributing decision authority to the most appropriate decision maker Distributing decision authority may be a key enabler in multiplying system capacity by minimizing workload bottlenecks

4. DAG-TM Airborne Componentin Context • Mature-state focus • Complements near-term ASAS applications research • Characterization of mature-state feasibility, benefits potential, and system requirements is important, even for evolutionary modernization • Why must we consider such a challenging solution? No other proposed paradigm has potential to • accommodate expected growth in airspace operations – we must consider system that accommodates a threefold capacity increase • Projected increases in air carriers and air cargo • New class of small aircraft designed for point-to-point operations • adapt to demand in a cost-effective way • Increased traffic within region  increased CNS infrastructure • provide robustness to system failures • Increased number of human decision makers  greater redundancy • Redundant CNS infrastructure

5. DAG-TM Airborne Component Benefits Potential • Growth scalability for airspace capacity • More aircraft can be accommodated in a sector if a portion of them are self-managing • Each new autonomous aircraft in the system adds to the surveillance and separation provision infrastructures • Constraints due to controller workload are reduced through change in controller’s job from centralized control to traffic flow management • User flexibility to optimize VFR flexibility with IFR protection leads to reduced direct operating costs • Removal of “flow control” ground-hold restrictions based on en route and destination weather forecasts or ATC “saturation” • Reduction or removal of delays involved in waiting for flight plan approval • Time and fuel use during flight • Safety and reliability • Increased redundancy of traffic control • Economic scalability • Distribution of system modernization costs • For NAS users, more direct relationship between capital/recurring investments and benefits

6. Autonomous (AFR) Aircraft Concept Integrates: $+J Mixed operations Q Q Operational constraints Cost management, Passenger comfort User flexibility Q Q IFRpriority Q Airborne separation Q Q Q AeronauticalOperational Control Q Hazard avoidance Q Fleet management Q Priority rules Managed (IFR) Aircraft Q Q Special Use Airspaceavoidance Q Q IFR trajectorymanagement Q Maneuver restrictions Q Q Q Q Q Q Q Q Q Air Traffic Service Provider IFR and AFR traffic flow management Q User-determined optimal trajectory Crossing restrictions Terminal area En Route Free ManeuveringOperations Overview

7. En Route Free Maneuvering Roles & Procedures for Air/Ground Interaction Autonomous Flight Rules (AFR) Aircraft Air Traffic Service (ATS) Provider • Maintains separation from all aircraft • Extra separation margin given to IFR aircraft to minimize impact on ATS Provider • Ensures no near-term conflicts are created by maneuvering or changing intent • Selects and flies user-preferred trajectory • No clearance required in AFR operations (like VFR) • Trajectories selected to meet flight safety, fuel efficiency, performance limitations, and company preferences • Includes avoiding convective weather and maximizing passenger comfort • Unrestricted route & altitude except SUA’s established by ATS Provider • Conforms to TFM constraints • Adjusts path and speed to meet Required Time of Arrival (RTA) received from ATS Provider • Notifies ATS Provider if unable to meet RTA or crossing restrictions; request new assignment • Conformance required to gain terminal area access • Separates IFR aircraft only and monitors IFR conformance to flow/airspace constraints • Uses advanced tools and data link for enhancing IFR operations efficiency and tightening TFM tolerances • Establishes flow & airspace constraints for system-wide & local TFM • Meters AFR and IFR arrivals by assigning RTA’s (AFR) and speeds/vectors or data link trajectories (IFR) • Provides AFR aircraft an IFR clearance to enter terminal area (at which time AFR becomes IFR) • Not responsible for monitoring AFR ops • Exception: Avoids creating near-term conflicts between AFR/IFR aircraft when maneuvering IFR aircraft • AFR aircraft treated much like VFR aircraft; relies on AFR aircraft to separate from IFR aircraft • Not responsible for ensuring AFR aircraft meet RTA Airline Operational Control (AOC) • Manages strategic fleet operations

8. Conflict prevention band Conflict resolution trajectory Conflict region Airspace constraint Conflicting aircraft Ownship Intent and State Detection => Intent Only Strategic Strategic & Tactical Tactical Resolution => 5 min 2 min 0 min 10 min Time to Loss of Separation En Route Operations – Crew Perspective (1/3) Research Prototype Navigation Display (MD-11) • AOP: Planning system for autonomous operations • Long-term conflict detection(nominal 20+ min.) • Resolution through modified FMS route • Conflict(s) resolved without creating new conflicts with traffic or airspace • Pilot decision is strategic; resolution provides complete solution. Tactical information is also provided • Aircraft state- and intent-based conflicts • Traffic and area hazards • Intent-based CR algorithm • Iterates with FMS trajectory generation function to achieve “flyable” conflict-free trajectory • Not limited by imposed constraints (e.g., required time of arrival) • Determines optimal trajectory based on user-specified objectives

9. En Route Operations – Crew Perspective (2/3) • Several aircraft trajectories possible, depending on ownship pilot actions. All are probed for conflicts: • Planning (typically the FMS flight plan) • Commanded (current autoflight config - “no button push”) • State vector • Path reconnect (LNAV/VNAV not engaged) • Conflict prevention alternatives • Provisional (trial planning) FMS • Provisional MCP • Maneuver restriction bands (intent-based “no-go”) • Collision avoidance bands (state-based “no-go” for RTCA “CAZ”) • Conflict resolution alternatives • Fully automatic (full LNAV/VNAV solution) • Semi-automatic (pilot specifies resolution DOFs) • MCP targets • State Research Prototype Navigation Display (B777) Automatic Resolution (LNAV/VNAV engaged)

10. Example of Multi-Trajectory Conflict Probing Movie clip speed: 3x

11. ATSP-definedmaneuveringcorridor Meteringboundary Maneuver within prescribed corridorsfor optimal spacing Adhere to metering assignment for initial spacing and sequence Merge with converging traffic streams Unequipped Aircraft Adhere to runway assignment and sequence for load balancing, throughput Phase1 Fly with precision for optimal spacing Capacity-Constrained Terminal Arrival Operations Terminal airspace

12. Phase 1 Crew Decision Support Capability Advanced Terminal Area Approach Spacing (“ATAAS”) Algorithm • Provides speed commands to obtain a desired runway threshold crossing time (relative to another aircraft) • Compensates for dissimilar final approach speeds between aircraft pairs • Speeds based on a nominal speed profile • Includes wake vortex minima requirements • Provides operationally reasonable speed profiles • Provides guidance for stable final approach speed • Provide for any necessary alerting

13. Speed profile added to existing procedure Phase 1 Terminal Arrival Operations – Crew Perspective (1/3) Procedures based on an extension of existing charted procedures

14. Phase 1 Terminal Arrival Operations – Crew Perspective (2/3) Electronic Attitude Director-Indicator (EADI) B757 • Numeric display of ATAAS speed guidance • ATAAS speed coupled to F/S indication • Mode annunciation

15. ATAAS data block (commanded speed, mode annunciation and assigned time interval, lead traffic ID and range) { Lead traffic highlighted Lead traffic history trail Spacing position indicator Phase 1 Terminal Arrival Operations – Crew Perspective (3/3) Navigation Display B757

16. APPR SPACING 1/1 SELECT LEAD <PROF SPEED AAL846 > AAL941> LEAD AIRCRAFT UAL903 > COA281 CURRENT SPACING 128 SEC UAL225> UAL903> APPR DATA> APPR SPACING 1/1 <NEW LEAD SPACING INTERVAL --- CURRENT DISTANCE 7.8 LEAD GROUNDSPEED 271 KTS APPR DATA> APPR DATA APPROACH SPEEDS NASA557 135 KTS UAL903 130 KTS MIN DISTANCE 4 NM APPROACH WINDS 180 /19 < APPR SPACING Phase 1 Terminal Arrival Operations – Crew Perspective (4/4) FMC CDU Pages Select lead aircraft Enter assigned spacing interval Enter final approach speeds, minimum separation, airport winds

17. Closing Remarks (1/2) • The DAG-TM Airborne Component is part of a future mature-state airspace system consisting of coexisting non-segregated distributed and centralized networks. These networks provide system-level optimization, individual user flexibility to optimize, and a gradual modernization transition path. • Autonomous Flight Rules (AFR) is introduced as a new option for aircraft flight operations, and produces the distributed network in which aircraft exercise autonomous flight management capabilities to meet TFM constraints, maintain separation from all other aircraft, and to achieve user optimization objectives. • IFR operations are centrally managed by ground systems and controllers, and mature independently from AFR operations through evolutionary enhancements to ground automation. • AFR and IFR operations coexist in the same en-route and terminal-transition airspace, and AFR flights give way to IFR operations. AFR and IFR traffic are merged for terminal arrival using ground-based local TFM. Terminal operations at capacity-limited airports are fully IFR.

18. Closing Remarks (2/2) • Terminal area throughput is maximized through integrated enhancements in ground and airborne capabilities • Airborne capability to execute strategic spacing clearances accounting for dynamic wake vortex conditions to help maximize throughput. • Ground automation to enable full integration of spacing and non-spacing aircraft. • AFR operations permit growth scalability of the airspace system by accommodating significant traffic growth without exponential growth in ground infrastructure. Enhanced IFR operations provide access to all users with minimal impact from AFR operations. • Users have incentive to equip for AFR through relief from flow management and planning acceptance restrictions

19. Backup Slides

20. En Route Operations – Crew Perspective (3/3) FMC CDU Pages 1. Conflict advisory information displayed 3. Crew opts for alternative resolution. List displayed 2. Crew opts to resolve all conflicts. Recommended resolution presented on ND 4. Crew uploads resolution to FMS mod route

21. Air Traffic Control Technologies Overview • En route tools and display support for trajectory-based traffic management • Meet time cruise and descent speed advisories • Multi-aircraft trial planning for transition airspace • Multi-aircraft trajectory preview display • Datalink for information exchange and trajectory clearances • Toolbar for clearance input, datalink, and display control • TRACON tools and display support for self-spacing operations • Spacing interval advisory • History circles for conformance monitoring • Human-in-the-loop simulation with pilots and controllers • Dallas-Fort Worth airspace - ~ 8 North West en route & TRACON sectors • Arrival rush problem - ~ 90 aircraft • Multi-fidelity aircraft simulators with advanced avionics

22. Air Traffic Control Automation for DAG-TM CPDLC capability “shortcut” window Color coded arrivals & overflights CTAS conflict list Trial plan conflict list “dwelled” aircraft highlighting Route trial planning Speed advisories FMS route display TMA timeline Need some labels for the items on this slide. Data entry & display toolbar

23. 0 100 nm Strategic and Tactical Airborne Conflict Management FY2002 Piloted Simulation of Autonomous Aircraft Operations, NASA Air Traffic Operations Laboratory Constrained En-Route Scenario (b) Varied proximity of“Special Use Airspace” (a) Variedstandard forlateralseparation Traffic density: 15 -18 a/c per 10K nm2 Waypoint withrequired time of arrival Red bars: number and percentage of pilots that experienced at least one 2nd generation conflict Research objective: Investigate strategic and tactical conflict management tools in close proximity to traffic, airspace hazards, and traffic flow management constraints • Safe achievement of flight operational objectives was not affected by (a) reducing lateral aircraft separation requirements or (b) significantly constraining the available airspace for maneuvering • Use of strategic conflict management techniques strongly reduced the propagation of traffic conflicts by accounting for all regional constraints and hazards in the conflict solution

24. Airborne Spacing Flight Evaluation Flight activity recently completed at Chicago O’Hare • Validation of full-mission simulator study results, which showed large benefits achievable and very low impacts on flight crew workload • Vectoring scenarios (reflection of current day operations) • Aircraft followed ground track of leading aircraft, which was vectored by controller Initial Analysis • Results very comparable to simulation, even in presence of widely varying winds (35+ knot tailwind to headwind changes on final) • Spacing Performance • Most runs accurate to ±3 seconds at threshold crossing; many within 1 second (~200 ft)