National Aeronautics and Space Administration ADS-B In-Trail Procedures Overview of Research Results Presented to the ASAS TN2 Workshop September 2007

National Aeronautics and Space Administration

ADS-B In-Trail ProceduresOverview of Research Results

Presented to the ASAS TN2 WorkshopSeptember 2007

Kenneth M. JonesCrew Systems & Aviation Operations BranchNASA Langley Research CenterHampton, Virginia 23681-2199(757) 864-5013E-mail: [email protected]

2

Enhanced Oceanic Operations Objective and Rationale

• Research Objective

– Develop methodologies, concepts, and procedures to reduce separation requirements for future air transportation systems using airborne ADS-B and Airborne Separation Assistance Systems (ASAS)

• Why airborne ADS-B and ASAS?

– Both are key components of NextGen and SESAR concepts of operation to accommodate much higher densities of air traffic

– Research and development of early ASAS applications will provide:• Insight into the nuances and details necessary to reduce separation requirements

for the future

• Incentive for operators to voluntarily equip with transformational technologies and for manufacturers to develop suitable hardware and software

• Why Oceanic?

– Unique domain for conducting and obtaining valuable research data • Can make dramatic improvements (reductions in separation) with ADS-B and

ASAS without the need to develop completely new technologies

• These reductions can result in significant operational benefits

• Air traffic environment that is open to new technologies and procedures

3

• Efficient oceanic operations require flight level changes– Climbs required for optimal

performance as fuel is burned

– Altitude changes for favorable winds or to avoid turbulence

ASAS Enabled Climbs

Sub-Optimal Cruise

Optimal

• Current oceanic operations limit opportunities for flight level changes– Many flights operate along the same routes at the same time– Reduced surveillance performance (compared with radar) results in large separation

minima for safe procedural separation – Large separation minima often restrict aircraft from making desirable altitude changes

• Use of ASAS applications (including airborne surveillance and onboard automation) enable flight level changes which have operational benefits

– ADS-B ITP is an early phase of a multi-phase approach

Enhanced Oceanic Operations Oceanic Challenges and Incentives

4

FL360

FL340

FL350

Standard Separation

blue = ADS-B transceiver and onboard decision support systemred = ADS-B out minimum required

• Flights can be held at non-optimal altitudes due to traffic conflicts at intermediate altitudes

• ADS-B In-Trail Procedure application based on an approved ICAO procedure– Controller separates aircraft based on information derived from cockpit sources and relayed

by the flight crew

• Receipt of ADS-B data from surrounding aircraft; use of a cockpit display and software provides data to qualify the aircraft for the maneuver

– No airborne monitoring during climb required– Controller retains responsibility for separation

• The pilot requests, and the controller may approve, a flight level change based on information derived in the cockpit and the controller’s awareness of the full traffic picture

ADS-B In-Trail ProceduresFollowing Climb Example

5

In Trail Procedure (ITP)

FL360

FL340

FL350

Standard Separation

blue = ADS-B transceiver and supporting display systemred = ADS-B out minimum required

white = no ADS-B requirements

Desired Altitude

Current Separation

ALLOWEDBLOCKED

Enhanced Oceanic Operations: Phase 2Standard Climb vs ITP Climb

Sequence of Events

Realize that a climb is desiredStandard climb?

ITP following climb?

Request ITP following climb

Unable

Valid

Approved

ITP speed/distance criteriaGroundspeed difference < 20 kt and difference in range > 15 nm

orGroundspeed difference < 30 kt and difference in range > 20 nm

6

• Concept Development

– Concept of operations development for normal and non-normal operations

– RTCA/EUROCAE Requirements Focus Group (RFG) Airborne Traffic Situation Awareness ITP (ATSA-ITP) application description

• Establish a single, globally accepted, concept of operations (domain independent)

• Safety and Performance Analyses

– Safety and collision risk analysis using probabilistic methods and Monte Carlo simulation for the ITP

– RFG ATSA-ITP safety and performance assessment work

– ICAO Separation and Airspace Safety Panel (SASP)

• Concept Evaluation

– Use of TMX to evaluate ITP climb opportunities and efficiency gains

– Evaluation of ITP and cockpit decision support tools in NASA Langley’s Air Traffic Operations Lab (ATOL): pilot perspective

– Evaluation of ITP operations: controller perspective

– Operational flight evaluation of ITP

ADS-B In-Trail ProceduresResearch Activities

7

• Experiment Overview– Evaluated ITP flight level change opportunities

– Simulation tool: TMX• Joint NLR/NASA medium fidelity batch simulator• Includes pilot model, ATC model, CPDLC model, ITP procedure logic

– Focused on North ATlantic Organized Track Structure (NATOTS)• Simulation of current day operations used as a baseline• Distribution of traffic and track loading based on current day NATOTS data

– Varied traffic densities and ADS-B equipage levels

– Modeled ITP flight level changes as well as standard flight level changes that result from increased situation awareness

– Over 900 unique traffic flows simulated

• Preliminary Results– Operational benefits are obtained with the use of an onboard ADS-B receiver

and traffic display

– There are significant operational benefits from situation awareness

ADS-B In-Trail ProceduresBatch Simulations

8

Track V

31000

32000

33000

34000

35000

36000

37000

38000

39000

40000

41000

10000 15000 20000 25000 30000 35000 40000

2000

1000

0

-1000

-2000

-3000

-4000

-5000


Altitude(feet)

Simulation Time (seconds)

Difference in feet

Difference between FMS Recommended Altitude and Altitude Attained prior to Track ExitModerately Loaded Track, Medium Density, No ADS-B Equipage

9

Track V

31000

32000

33000

34000

35000

36000

37000

38000

39000

40000

41000

10000 15000 20000 25000 30000 35000 40000

2000

1000

0

-1000

-2000

-3000

-4000

-5000


Altitude(feet)


Difference in feet

Difference between FMS Recommended Altitude and Altitude Attained prior to Track ExitModerately Loaded Track, Medium Density, 90/80 (ADS-B Out/ADS-B In) Equipage

10


• At track exit– No ADS-B equipage case: 27% of aircraft are at FMS recommended altitude– 90/80 equipage case: 58% of aircraft are at FMS recommended altitude

• During the crossing:– No equipage: 2 out of 52 aircraft climbed– 90/80 equipage case: 24 out of 52 aircraft made altitude changes with an

average change of altitude of 1417 feet per aircraft

No ADS-B Equipage 90/80 Equipage

31000

32000

33000

34000

35000

36000

37000

38000

39000

40000

41000

10000 15000 20000 25000 30000 35000 40000

31000

32000

33000

34000

35000

36000

37000

38000

39000

40000

41000

10000 15000 20000 25000 30000 35000 40000

11

0

10

20

30

40

50

60

70

80

90

100

NO ADS-B IN

ADS-B IN EQUIPPED


Fuel Savings (lbs)

Nu

mb

er

of

Airc

raft

Variation of Fuel SavingsMedium Density, 90/80 Equipage

0

5

10

15

20

25

30

35

12

• ASAS applications require hardware, software and an appropriate crew interface

• Options for crew interface include primary field of view (e.g. PFD), forward field of view (e.g. EICAS or TCAS) or other secondary fields of view (e.g. EFB mounted on the side)

• Display Development

– Initial display designs conceptualized

– Survey questionnaires distributed to 1500 oceanic line pilots

– Design revised based on the 250 survey responses received

ADS-B In-Trail ProceduresConcept Validation Study - Flight Crew Perspective

13

• Research Objectives– Assess the Validity of the ITP– Assess Pilot Acceptability of the ITP

• Part-Task Human-In-The-Loop Experiment– Conducted in ATOL September 2006– 23 pilots over a 4 week period, 16 scenarios flown – Participants were 777 and/or 747-400 pilots with current oceanic experience

• Developed prototype Flight Manual Bulletin and Electronic Flight Bag (EFB) interface


• NASA Air Traffic Operations Lab (ATOL)– Medium-fidelity, part-task, air

traffic simulation environment

– Designed for exploration of inter-aircraft, aircraft/airspace, and air/ground interactions

– Demo available

14

• Results– Procedure was rated as both valid and acceptable– Workload was determined to be similar to standard level changes (no significant increase)

• Rating of 1: Minimal Operator Effort • Rating of 4: Moderately High Operator Effort• Rating of 7: Maximum Operator Effort • Rating of 10: Task Can Not Be

Accomplished– Pilots found the increased situation awareness provided by the display very useful– Report to be published fall 2007


1.581.20

1

2

3

4

5

6

7

8

9

10

Standard ITP

Requested Flight Level Change Maneuver

Mea

n W

orkl

oad

Ratin

g

1.421.32 1.481.951.611.611.51.05

0123456789

10

Requested Flight Level Change Maneuver

Mea

n W

ork

load

Rat

ing

Mean Modified Cooper-Harper (MCH) workload ratings associated with requested flight level change maneuvers

15

• Research Objectives– Assess whether ITP is valid from the perspective of an air traffic controller

– Assess whether ITP is acceptable to air traffic controllers

• Experiment conducted August 2007– 12 controllers from two different procedural sectors

– Each controller dealt with multiple ITP scenarios in three 50 minute sessions

• Preliminary results– Workload is no higher than current day operations

– Most controllers thought they would use it more than once per shift

– Recommendations for ITP phraseology were suggested

– Would prefer preformatted CPDLC messages to free text

– ITP could be acceptably applied using VHF voice

ADS-B In-Trail ProceduresConcept Validation Study - Controller Perspective

16

• Goal of Operational Evaluation of ITP– Evaluate the ITP concept in an operationally relevant environment

• Objectives of Operational Evaluation of ITP– Assess operational performance and economic feasibility of ADS-B ITP

– Assess validity of simulation results

– Establish basis for global ADS-B ITP implementation and/or follow-on work

• Approach– Conduct evaluation on revenue flights

– Support an evaluation in surveillance airspace

– Migrate to operational evaluation in non-surveillance airspace

• Results we will Obtain from an Operational Evaluation– ADS-B data quality and reception ranges

– Frequency of use of ITP

– “Real world” aspects of the concept and implementation

– Aircraft system architecture investigation and evaluation

– Flight crew acceptance and usage of ADS-B In data for situation awareness

– Basis from which to develop future applications

ADS-B In-Trail ProceduresOperational Flight Evaluation

17

• ICAO Separation and Airspace Safety Panel

– ICAO authorization of a new separation standard required for flight in oceanic airspace

• Presentations given to SASP and Subgroups

– Developed and presented an ADS-B ITP collision risk analysis to the Mathematics Sub-Group

• Methodology and results well received

• Anticipating approval during late 2007

– Project Team 6 (Longitudinal Separation subgroup) adopted ITP as a part of their work program

• Australia presented a paper and proposed amendment to ICAO Doc. 4444 (PANS ATM) for ITP

• Anticipate approval in 2008

• SASP recognized this is as one of the first new separation standards that involves significant airborne ADS-B roles and responsibilities

ADS-B In-Trail ProceduresInternational Collaboration – ICAO SASP

18

Summary

• ADS-B In-Trail Procedures– Airborne ADS-B enabled climbs and descents through blocked flight levels

– More predictable and fuel-efficient operations in non-surveillance airspace

• Summary of Results– Batch Results

• Operational benefits are obtained with the use of an onboard ADS-B receiver and traffic display

– Concept Validation Study – Pilot Perspective• Procedure was deemed to be acceptable and valid• Workload was determined to be similar to standard level changes

– Concept Validation Study – Controller Perspective• Procedure was deemed to be acceptable and valid• Workload was determined to be similar to standard level changes

– ICAO SASP• Recognized ADS-B ITP as one of the first new separation standards that involves

significant airborne ADS-B roles and responsibilities

19

Back Up Slides

20

ADS-B In-Trail Procedure (ITP) Flight Crew Checklist

21


Track X

31000

32000

33000

34000

35000

36000

37000

38000

39000

40000

41000

10000 15000 20000 25000 30000 35000 40000 45000

2000

1000

0

-1000

-2000

-3000

-4000

-5000

Altitude(feet)

Difference in feet

Difference between FMS Recommended Altitude and Altitude Attained prior to Track ExitBusiest Track, Medium Density, No ADS-B Equipage


24% of aircraft at FMS recommended altitude

22

Track X

31000

32000

33000

34000

35000

36000

37000

38000

39000

40000

41000

10000 15000 20000 25000 30000 35000 40000 45000

2000

1000

0

-1000

-2000

-3000

-4000

-5000


Altitude(feet)

Difference in feet

Difference between FMS Recommended Altitude and Altitude Attained prior to Track ExitBusiest Track, Medium Density, 90/80 (ADS-B Out/ADS-B In) Equipage


43% of aircraft at FMS recommended altitude

23


• At track exit– No ADS-B equipage case: 24% of aircraft are at FMS recommended altitude– 90/80 equipage case: 43% of aircraft are at FMS recommended altitude

• During the crossing:– No equipage: 1 out of 83 aircraft climbed– 90/80 equipage case: 26 out of 83 aircraft made altitude changes with an

average change of altitude of 1385 feet per aircraft

31000

32000

33000

34000

35000

36000

37000

38000

39000

40000

41000

10000 15000 20000 25000 30000 35000 40000

31000

32000

33000

34000

35000

36000

37000

38000

39000

40000

41000

10000 15000 20000 25000 30000 35000 40000

No ADS-B Equipage 90/80 Equipage

Documents

National Aeronautics and Space Administration ADS-B In-Trail Procedures Overview of Research Results Presented to the ASAS TN2 Workshop September 2007