Federal AviationAdministrationSurveillance and

Broadcast Services

ADS-B In-Trail Procedures

Presented to the ASAS TN 2.5 WorkshopNovember 2008

Kenneth M. JonesFAA Surveillance and Broadcast Services Program Office

Surveillance and Broadcast Services

For Official Use Only2Federal Aviation

Administration

• The Aviation Rulemaking Committee (ARC) – ARC encouraged SBS Program to examine how operational benefits

of ADS-B could be optimized before compliance with a nationwide ADS-B mandate

• Objective– Develop a globally accepted, airborne ADS-B application that

provides operational benefits prior to required compliance with the ADS-B mandate

• Approach– Conduct an operational evaluation of ADS-B ITP that delivers more

efficient oceanic operations

• Anticipated Outcomes– Insight into the operational aspects of airborne ADS-B– Catalyst for change to regulatory process– Validate economic benefits of ADS-B ITP– Provide a growth path to future applications

ADS-B In-Trail Procedures

Surveillance and Broadcast Services

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Administration

FL360

FL340

FL350

Standard Separation

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

• ADS-B In-Trail Procedures– ADS-B ITP separation standard relies on airborne ADS-B data

evaluated by the flight crew which permits climb request– Controller retains separation responsibility and approves clearance

based on knowledge of complete traffic situation• No airborne monitoring during climb required

• ADS-B In-Trail Procedures are airborne ADS-B enabled climbs and descents through otherwise blocked flight levels

ADS-B In-Trail ProceduresFollowing Climb Example

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In Trail Procedure (ITP)

FL360

FL340

FL350

Standard Separation

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

white = no ADS-B requirements

Desired Altitude

Current Separation

ALLOWEDBLOCKED

Sequence of Events StatusPilot requests following climb

ATC verifies std climb criteria

Pilot verifies ITP climb criteria

Pilot requests ITP climb from ATC

Unable

Valid

Approved

ADS-B In-Trail ProceduresStandard Climb vs ITP Climb

ATC verifies ITP climb criteria

ATC grants ITP following climb

Valid

Pilot ITP Speed/Distance Criteria  Ground Speed ∆ Range ∆

or< 20 kt > 15 nm

< 30kt > 20 nm

ATC ITP criteria• Closing Mach ≤ 0.04 • Available target altitude

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ADS-B In-Trail ProceduresDevelopment Activities• Concept and Standards Development

– RTCA/EUROCAE Requirements Focus Group (RFG) • Airborne Traffic Situation Awareness ITP (ATSA-ITP) Safety, Performance and

Interoperability Requirements (SPR) Document– Interoperability requirements, Operational and Service Environment Description (OSED),

Operational Safety Assessment (OSA), Operational Performance Assessment (OPA)

Approved Summer 2008!

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Administration

• ICAO Separation and Airspace Safety Panel (SASP)– Adopted ADS-B ITP as part of their work package in November 2006– Developed ADS-B ITP collision risk analysis (approved by SASP October

2008)– Longitudinal Separation subgroup has proposed an amendment to ICAO Doc.

4444 (PANS ATM) for ITP

• Still requires broader ICAO approval

ADS-B In-Trail ProceduresConcept and Standards Development

Approved by SASP October 2008!

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Administration

• ADS-B applications require an appropriate crew interface

• Options for interface include primary field of view (e.g. PFD), forward field of view (e.g. EICAS) or other secondary fields of view (e.g. EFB)

• EFB chosen as a potentially lower cost retrofit option

• Display Development– Initial display designs conceptualized

– Survey distributed to 1500 oceanic line pilots; design revised based on the 250 survey responses received

ADS-B In-Trail ProceduresRetrofit Display Option

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• 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– 26 pilots over a 4 week period, 16 experiment scenarios flown – Participants were 777 and/or 747-400 pilots with current oceanic experience

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

• Results– Procedure was rated as both valid

and acceptable– Workload similar to standard level

changes (no significant increase)– Pilots found the increased situation

awareness provided by display very useful

– Results available as NASA TP 2008-215313

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Administration

• 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 in Airservices Australia’s TAAATS simulation facility– 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

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Administration

• Goal of Operational Evaluation of ITP– Conduct ITP operations in an oceanic environment on revenue flights

• Objectives of Operational Evaluation of ITP– Validate operational performance of ADS-B ITP

– Assess economic benefits of ADS-B ITP

– Establish framework for global ADS-B ITP implementation and follow-on airborne ADS-B applications

• Initial operations in the SOPAC– Favorable business case

– DO-260 signal issues appear manageable

• Migrate to the PACOTS– Appears to be a significant, compelling benefit mechanism

• Significant traffic interactions• Substantial fuel savings potential• Variety of aircraft types

ADS-B In-Trail ProceduresOperational Evaluation/Trial

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• About 10% of flights remain within 60nmi and 4,000 ft from other traffic for longer than 1 hr

• Traffic interactions are infrequent and very hard to predict

• Consequently, variations in fuel burn can be significant

• Flights board contingency fuel to avoid unplanned fuel stops

YSSY to KLAX

Jan. 12, 2004KLAX to YSSY

January 2004

ADS-B In-Trail ProceduresSOPAC Business Case

• Benefit mechanism assumptions– Flights operate MTOGW; reduction in contingency fuel replaced with additional cargo

revenue– Airline policy decision to carry less contingency fuel– Statistical analysis has shown that in the SOPAC, an airline could choose to keep the

same risk of unplanned fuel stops and board 300 lb less fuel with ITP

• 300 lb contingency fuel reduction results in a benefit per equipped aircraft of approximately 202K/year; potentially more

• Return on Investment for a carrier – one year!

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• Certification and verification of DO-260 signal– Current business case assumes a certified DO-260

signal

– Need to verify the signal is coming from an approved system or to verify the integrity of the signal received

ADS-B In-Trail ProceduresOperational Evaluation/Trial – Technical Issues

• Electronic Flight Bag (EFB)– Assumed an EFB installation for

retrofit aircraft

– Guidance indicates Class III EFB is the best solution

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Administration

Increased Delegation of Separation to

the Flight Deck

• Phase 1 –ADS-B In-Trail Procedures– Flight level changes allowed based on cockpit derived data

• No delegation of separation authority to the flight deck

– Increased situation awareness

• Phase 2 – Limited, Delegated Oceanic Separation Procedures– Enhanced ITP (ASEP-ITP)

• Limited delegation of separation authority to the cockpit during the maneuver

• Simplified procedure, reduced separation distance

– In-Trail Follow Procedures (ASEP-ITF)• Reduce co-altitude separation distances• Pair-wise separation using spacing techniques• Potential for big payoff in the North Atlantic

• Phase 3 – Airborne Self-Separation Corridors (SSEP-ITP)– Aircraft allowed to self-separate on approved corridors

• Potential for Significant Fuel Savings in Phases 2 and 3!

Enhanced Oceanic OperationsPhased Approach

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• Summary– ITP is cost beneficial to airlines in the Pacific

– ITP using certified DO-260 signal produces an early payback in the SOPAC

– An 747-400 with a certified ADS-B ITP system will receive immediate benefit in the SOPAC and be ready for use in other areas when authorized

• Next Steps– ANSP and private sector partnership development

ADS-B In-Trail ProceduresSummary and Next Steps