Advanced Air Transportation Technologies Langley Research Center Evaluation of a Time-Based Airborne Inter-arrival Spacing Tool Presented by: Gary W. Lohr NASA Langley Research Center Hampton, VA ATM 2003 Conference June 25, 2003

Advanced Air Transportation Technologies Langley Research Center Concept Overview Benefits Concept, Tool Implementation Interfaces Simulator Study Flight Evaluation Current and Future Work Outline

Advanced Air Transportation Technologies Langley Research Center Terminal Arrival Concept ATSP establishes the operational flow Demand and capacity estimated; TRACON flow rates established Arrivals metered at TRACON boundary for initial sequencing & spacing Approach spacing and merging clearances given to equipped aircraft Speed and vectoring clearances given to unequipped aircraft Aircraft meet system goals through operational modes Flexibility exercised in maneuvering corridors to achieve system and user efficiency Approach Spacing provides optimized traffic flow Transition to stabilized approach and normal landing Appropriate clearances Issued as possible after aircraft enter terminal area

Advanced Air Transportation Technologies Langley Research Center Phased approach toward an enhanced terminal area environment Phase 2 Merge Phase 1 In-trail Phase 3 Maneuver          Enhanced Terminal Operations

Advanced Air Transportation Technologies Langley Research Center Approach Spacing Concept What is Approach Spacing? A concept designed to improve runway throughput Uses ADS-B aircraft state data and other information, coupled with an onboard algorithm to provide guidance to the pilot to achieve precise spacing of aircraft Includes supporting procedures for both the air and ground sides The Spacing Tool is at the heart of the Approach Spacing Concept, so…

Advanced Air Transportation Technologies Langley Research Center In-Trail Spacing UAL sec. NWA16 H +90 sec. N6113T +120 sec. UAL sec. AAL sec. ATC assigned spacing based on desired arrival rate and wake vortex separation standards Not restricted to “fixed routes”

Advanced Air Transportation Technologies Langley Research Center Benefits Increased runway throughput when instrument approaches are in use; potential for consistent spacing with visual approaches Reduction in voice radio communications, thereby reducing communication congestion and potential communication error In-trail aspects of operation are possible with minimal infrastructure changes

Advanced Air Transportation Technologies Langley Research Center Results of Mitre Monte-Carlo Studies 2.5 nmi Separation Standard* (Assumed baseline throughput -- about 32 / hour; LaGuardia traffic mix, 1 “violation” per 1000 operations) *From Mitre presentation, Nov 2001: Hammer and Wang; corrected Full Equipage MITRENASA Average inter-delivery rate Throughput (aircraft/hour) Total number of violations of separation standard per 1,000 aircraft with separation no greater than 14,000 feet Operationally significant Monte Carlo Analysis

Advanced Air Transportation Technologies Langley Research Center ATAAS Implementation Based on an extension of existing charted procedures Designed to enhance system-wide capacity (versus single aircraft performance) As much as possible, supporting crew/controller procedures should reflect current-day operations Speed profile added to existing procedure

Advanced Air Transportation Technologies Langley Research Center 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 Includes wake vortex minima requirements Provides operationally reasonable speed profiles Provides guidance for stable final approach speed Provide for any necessary alerting Tool - Implementation

Advanced Air Transportation Technologies Langley Research Center Pilot Interface Electronic Attitude Director-Indicator (EADI) Numeric display of ATAAS speed guidance Mode annunciation ATAAS speed coupled to F/S indication

Advanced Air Transportation Technologies Langley Research Center Pilot Interface (cont’d) Navigation Display Lead traffic highlighted Lead traffic history trail Spacing position indicator ATAAS data block (commanded speed, mode annunciation and assigned time interval, lead traffic ID and range) {

Advanced Air Transportation Technologies Langley Research Center Pilot Interface (cont’d) APPR DATA APPROACH SPEEDS NASA KTS UAL KTS MIN DISTANCE 4 NM APPROACH WINDS 180 /19 < APPR SPACING 1/1 SELECT LEAD <PROF SPEED AAL846> AAL941> COA281 > UAL225> UAL903> APPR DATA> Custom FMC CDU ATAAS pages Enter assigned spacing interval Select lead aircraft Enter final approach speeds, minimum separation, airport winds APPR SPACING 1/1 <NEW LEAD LEAD AIRCRAFT UAL903 SPACING INTERVAL CURRENT SPACING 128 SEC CURRENT DISTANCE 7.8 LEAD GROUNDSPEED 271 KTS APPR DATA> ---

Advanced Air Transportation Technologies Langley Research Center ATAAS Simulation Study Simulator Evaluation of the ATAAS Tool

Advanced Air Transportation Technologies Langley Research Center Experiment Objectives Pilot evaluation (acceptability) of: –Approach spacing tasks (including charts, procedures and use of ATAAS system) –ATAAS interface: Electronic Attitude Director-Indicator (EADI), Navigation Display (ND), and Flight Management Computer Control-Display Unit (FMC CDU) Pilot assessment of workload with different levels of automation Evaluation of algorithm performance when implemented on “real-world” equipment

Advanced Air Transportation Technologies Langley Research Center Facilities NASA Langley Integration Flight Deck (IFD) Simulator ATC lab facility with controller issuing scripted clearances Head-mounted eyetracker

Advanced Air Transportation Technologies Langley Research Center Pilot Procedures Simple set of pilot procedures Checklist outlines Pilot Flying (PF) and Pilot Not Flying (PNF) duties Similar to normal operations

Advanced Air Transportation Technologies Langley Research Center Test Matrix Eight subject pilots (single subject pilot) Eight arrival runs flown by each subject pilot Each subject pilot paired with confederate pilot Sufficient training time allowed in simulator for familiarization with ATAAS and speed control modes

Advanced Air Transportation Technologies Langley Research Center Simulation Results Threshold spacing interval within one second of target (A/T coupled) Spacing interval within ~5 seconds in all cases Standard deviation 1.3 to 1.7 seconds for all modes ATAAS System Performance

Advanced Air Transportation Technologies Langley Research Center Simulation Results (cont’d) Pilots rated the concept and ATAAS tool highly in all acceptability questions Overall procedure was rated highly, including phraseology and crew procedures No major objections or recommended changes to displays, clutter was not considered a problem. Minimum level of training recommended was video or computer-based, with simulator practice time

Advanced Air Transportation Technologies Langley Research Center Summary of Results Using ATAAS, subject pilots were able to easily manage speed to consistently achieve assigned spacing interval ATAAS pilot/controller procedures were easily assimilated into normal cockpit duties Amount of head-down time required to use ATAAS considered acceptable by subject pilots Proper training improves accuracy of results from the ATAAS system

Advanced Air Transportation Technologies Langley Research Center Flight Evaluation of the ATAAS Tool Chicago O’Hare International Airport (ORD) and Terminal Area

Advanced Air Transportation Technologies Langley Research Center Participants NASA – LaRC Spacing capable Rockwell Collins Spacing capable Not-Spacing capable Aviation Navigation Satellite Programs (ANSP)

Advanced Air Transportation Technologies Langley Research Center Required Equipment Two levels of equipage for aircraft participating in the Approach Spacing flights Spacing capable aircraft (ARIES and Sabreliner) Mode-S transponder (broadcasting basic ADS-B message) GNLU-930 (GPS Receiver) TCAS Unit Spacing algorithm Not spacing capable aircraft (Piper Chieftain) Mode-S transponder (broadcasting basic ADS-B message)

Advanced Air Transportation Technologies Langley Research Center Pre-departure Call for clearance Sabre, ARIES advise Chieftain – ready for taxi Chieftain calls ready for taxi Chieftain calls ready for TO Climbout Chieftain segregated Jets climbout on path or via vectors Expect 5K, 6K or 7K Select lead traffic Flt Plan – IFR “ORD BAE ORD” Rmk: ATAAS Flt Demo Target turn-on pt. for Chieftain Min. turn-on pt. for jets Stage for Spacing Chieftain vectored to IB route Sabre* vectored to turn-on ~7 nm behind Chieftain ARIES vectored to turn-on * In case of Sabre landing to re-fuel ARIES will close gap Chieftain Sabre, ARIES ORD- 10DME ORD- 15DME Flt crew reduces to final approach speed at FAF (continue to follow ATAAS) RNAV Scenario - Fly charted Route and altitude Vector Scenario - Chieftain depart fix on downwind heading and expect vectors, speed, alt. assign At altitude for turn-on to final (expt 4K or 5K) Runs terminate with low approach Aircraft should be At 170KIAS prior to turning final or 17nm for straight-in Generic ATAAS Path Approach Spacing nominally begins on the Inbound Leg

Advanced Air Transportation Technologies Langley Research Center Flight Scenarios Subsequent aircraft follow speed cues, follow lateral route Lead aircraft receives vectors to the FAC Nominal path for controller issued vectors to FAC Subsequent aircraft follow time history trail RNAV Route – STAR is FAC intercept Lead aircraft flies speed profile 210KIAS 170KIAS    Vectors to FAC   

Advanced Air Transportation Technologies Langley Research Center Scenario begins with two aircraft spaced at distance that allows for an aircraft to be sequenced between them   Flight Scenarios Vector scenario – simulated weather cell case Nominal traffic pattern to FAC Re-sequence - Vector Third aircraft assigned spacing behind “new” lead Second aircraft assigned spacing behind lead Lead aircraft receives vectors around storm cell to FAC                 

Advanced Air Transportation Technologies Langley Research Center Sample RNAV Path

Advanced Air Transportation Technologies Langley Research Center EXPECTED ORD RWYS

Advanced Air Transportation Technologies Langley Research Center Test Conditions, Schedule ARIES: NASA Pilots; Sabreliner: Rockwell-Collins pilots One pilot flying ATAAS guidance, other is safety pilot Twenty-eight runs flown: 11 RNAV scenarios, 17 Vector scenarios Prior training time in simulator for familiarization with ATAAS and speed control modes and scenarios Flights conducted during non-peak hours (~12AM through 4AM) Schedule: Flights conducted September , 2002

Advanced Air Transportation Technologies Langley Research Center Scenario Run List 1.(A) RNAV Route 2.(A) RNAV Route 3.(C) Vectors – Wx 4.(B) Vectors – Nom * 5.(D) Re-sequence 6.(B) Vectors – Nom 7.(C) Vectors - WX- (time permitting) 1. __________ 2. __________ 3. __________ 4. __________ 5. __________ 6. __________ 7. __________ 1. __________ 2. __________ 3. __________ 4. __________ 5. __________ 6. __________ 7. __________ 1. __________ 2. __________ 3. __________ 4. __________ 5. __________ 6. __________ 7. __________ Flt Period 1 Flt Period 2 Flt Period 3 Flt Period 4 * Two aircraft flying this scenario; Sabre on the ground Note 1 : Underlined scenarios indicates Auto-throttle coupled scenario (speed driven by ATAAS algorithm output); standard text indicates manual management of the throttles. In the event that auto-throttles are not operational, manual speed management will be used. Note 2 : Ordering of runs are planned to be the same for each day, however, ordering may change based on operational considerations. Blank lines provided in subsequent days to document changes

Advanced Air Transportation Technologies Langley Research Center Data Collection Objective data - State data for all aircraft Subjective data - Pilot questionnaire –Questions from simulator study questionnaire –Questions focusing on task of following lateral path of lead aircraft Other data - –Video taping of flight deck activities and ND –Comments from TRACON controller and pilots regarding Approach Spacing operation

Advanced Air Transportation Technologies Langley Research Center Results Quantitative Results for Spacing Interval with 90 Second Target Separation - ARIES only

Advanced Air Transportation Technologies Langley Research Center Results Qualitative Results - Pilot Comments and Researcher Observations Pilot Comments RNAV with Auto-throttle - easy operation Following path (lateral) of leading aircraft demanded attention, with practice can be integrated into pilot workload in the terminal area I found that I gained a much better understanding of how the algorithm worked in terms of iterating on the speed profile as I flew more scenarios Researcher Comments Use of the “V” Bar – could be distracting for in-trail operations, and might not be used as intended; would serve better purpose for other applications such as Visual Approaches, Merge or Maneuvering spacing operations. Pilots required little time to understand how the algorithm worked at a functional level

Advanced Air Transportation Technologies Langley Research Center Even pilots with limited flight time expressed positive comments regarding the Approach Spacing operation… Results

Advanced Air Transportation Technologies Langley Research Center Current and Future Work Continued analysis of the data from the flight activity Refinements to algorithm Further development of merge (Phase II) capabilities Simulator evaluation of merge operations Evaluation with the supporting ATSP ground tools

Advanced Air Transportation Technologies Langley Research Center Finally…