Oceanic ITP

Airborne Traffic Situational AwarenessAirborne Traffic Situational Awareness– – In-Trail Procedure (ATSA-ITP)In-Trail Procedure (ATSA-ITP)

Presented to the ASAS Thematic Network 2Presented to the ASAS Thematic Network 2

Malmo, SwedenMalmo, SwedenSeptember 27, 2005September 27, 2005

Stephane MarcheStephane MarcheKen JonesKen JonesTom GraffTom Graff

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ATSA - ITP

Background

– Oceanic Challenges

– TCAS In-Trail Climb/Descent

Airborne Traffic Situational Awareness – In-Trail Procedure– Overview

– Chronology of RFG activities

Summary

Outline

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ATSA - ITP

North Atlantic Organized Track SystemOverview and Technical Challenges

Solution

Compromise

Optimal

Extended periods out of radar coverage

Large longitudinal and lateral separation minima required for safe procedural separation

Most airlines want the same tracks and altitudes results in altitude “congestion”

Safe, efficient (from a traffic flow perspective) operations but many times not fuel efficient operations

Aircraft “stuck” at a non-optimal altitude due to traffic “congestion”

– For efficient operations, aircraft need to climb as they burn fuel

– Due to traffic congestion at higher altitudes, aircraft often restricted from climbing

Use airborne surveillance and onboard tools to facilitate altitude changes for greater fuel efficiency

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ATSA - ITP

South Pacific Oceanic RegionOverview and Technical Challenges

“Virtual tracks”– Two types of routes – Fixed and User Preferred

Routes (UPR)– Fixed routes do not account for wind or

weather (or airline efficiency considerations)– UPR’s – optimized routes generated by

individual customers (preferred solution)– Most UPR’s are generated by similar programs

based on same wind data so most end up on similar routes

Pairwise congestion– Aircraft leave the west coast of the United

States about the same time– Aircraft generally end up causing altitude

restrictions to each other a portion of the way into the flight

– Aircraft not able to operate as efficiently due to traffic conflicts

FL290

FL300

FL310

FL320

FL330

FL340

FL350

7 8 9 10 11 12 13 14 15 16

Time (hr)

Flight #1

Flight #2

Flight #3

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Oceanic Non-Radar AirspaceSummary of Problems

Extended periods out of radar coverage

Large longitudinal and lateral separation minima required for safe procedural separation at reporting points

Difficult for crew to get climb approval or predict when approval may be granted– Cleared for one altitude on entire track route (eg NATOTS)

– Pair-wise congestion preventing climbs when needed (eg SOPAC)

Must carry (and possibly burn) contingency fuel

Potential diversion if aircraft operates at significantly other than optimal altitudes due to traffic constraints

Difficult to escape a turbulent altitude due to pair-wise “congestion”

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ATSA - ITP

FL370

FL330

FL350

+20

Minimum 15 miles

RNG 20

TCAS In-Trail Climb

TCAS In-Trail Climb (1994) developed to allow aircraft to climb to more efficient altitudes

– Distance determined by pilot using TCAS display TCAS and voice radio used to positively identify traffic and determine the

distance behind traffic– Traffic positively identified by cycling transponder from “on”, to “stand-by” , back to “on”– Minimum distance = 15 miles– Maximum distance = TCAS Surveillance limit (typically 25-40 miles)

No change in pilot/controller separation responsibilities– ITC based on existing distance-based non-radar procedures

The TCAS In-Trail Climb procedure built on an ICAO approved DME procedure which allowed the controller to separate aircraft based on information derived

from cockpit sources and relayed by the flight crew

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ATSA - ITP

FL360

FL340

FL350

Current SeparationRequirement

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

As with TCAS in-trail climb, if traffic conflict geometry and dynamics are appropriate, controller can approve climb based on information derived in the cockpit

– No delegation of separation responsibility

– Controller approves climb with knowledge of all aircraft (including non-equipped aircraft) On-board system is used to provide required information and addresses TCAS ITC

deficiencies

– Use ADS-B “in” and on-board automation to provide target a/c flight ID, ground speed and range information

Eliminates need for communication with target a/c

Addresses ALPA concerns with TCAS ITC (cumbersome procedures, safety system cycled on and off, lack of flight ID)

Eliminates TCAS dropped targets

Airborne Traffic Situational Awareness - In-Trail Climb

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Oceanic in-trail climb safety case can be developed based on an update to the previously accepted TCAS ITC safety case

For increased utilization of the procedures, other maneuvers can be considered that utilize same equipment and similar procedures

Further safety analyses need to be performed for these additional maneuvers

In-Trail Procedure broken up into six maneuvers

– In-trail climb

– In-trail descent

– Leading climb

– Leading descent

– Combination of in-trail and leading climb

– Combination of in-trail and leading descent

Airborne Traffic Situational Awareness - In-Trail Procedures

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ATSA - ITP

Airborne Traffic Situational Awareness - In-Trail ProceduresIncreased Opportunities for Flight Level Changes

80 nm-80 nm

Restrictions based on today’s procedures and standards Co-speed @ Mach .80 10 minute separation, ~80 nm required No climbs allowed if other traffic are in the red hatched area

FL340

FL350

FL360

Opportunities for climbs using ATSA - ITP Maximum closure rate = 20 kts, minimum initiation range = 15 nm, minimum climb rate = 300 fpm No climbs allowed if other traffic are in the red hatched area

15 nm-15 nmFL340

FL350

FL360

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Airborne Traffic Situational Awareness - In-Trail Procedures Operator Benefits/Interest

Airline return on investment and resulting incentive to equip is key to any operational implementation

Airlines have been studying oceanic operations looking for potential improvements

– “Small” changes to operations can result in significant fuel savings (long “leg” lengths)– Oceanic operations compromise 30% of a domestic airline’s total annual fuel

consumption!

$0.40

$0.50

$0.60

$0.70

$0.80

$0.90

$1.00

$1.10

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

Domestic

International

Total

Source: Bureau of Transportation Statistics

Aviation fuel cost per gallon– Fuel costs increasing

"On average, fuel accounts for 16 percent of airline operating costs. Fuel prices are 55 percent higher than one year ago. This could add between $8 and $12 billion to our annual fuel bill and threatens to strangle our modest projected return to profitability. Instead of flying high, we could be left swimming in red ink.“

Giovanni Bisignani, Head, International Air Transport Association, 27 May 2004

– Flexible operations can also prevent flights from experiencing costly diversions

Potential fuel savings of ~$160,000 per airplane per year

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ATSA - ITP

Detailed concept of operations for improved oceanic operations

– Establish a single, globally accepted, Concept of Operations

– Results in a globally accepted set of standards for the procedure

Requirements Focus Group (RFG)

– Established to develop co-ordinated requirements across multiple ADS-B applications to harmonize avionics standards

Oceanic ADS-B ITP Application Description (Operational and Service Environment Description or OSED)

– ADS-B ITP Application Description development led by NASA and Airbus Co-Editors: Ken Jones (NASA), Stephane Marche (Airbus)

– Approximately 40 international participants contributed to the development of the document

– Three versions of the document produced and released internationally for comment

– Two international workshops held to address substantive issues

Airborne Traffic Situational Awareness - In-Trail ProceduresDetailed concept of operations

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Document Status and StatisticsChronology

ATSA-ITP OSED version 1.0 sent to RFG members 11 April 2005– Comments requested from RFG members by 22 April 2005– Received 295 comments on version 1.0– The comments were very good and many were accepted

RFG ATSA-ITP OSED Meeting– Held 17-19 May, 2005 in Washington, DC– Addressed major issues on concept and phase diagrams– Resolved most issues and had very few open items; most open items have since been

closed (others incorporated into the next set of comments)

ATSA-ITP OSED version 2.0 sent to RFG members 10 June 2005– Commenters were asked to self select the priority of the comments (high, medium, low

or editorial)– Comments requested from RFG members by 22 June 2005– Received 260 comments on version 2.0– Majority of the comments were either “low” or “editorial”

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Document Status and StatisticsChronology (continued)

ATSA-ITP OSED meeting held at RFG/6– Held July, 2005 in Malmo, Sweden– Addressed issues on concept and phase diagrams– Resolved all the major issues

ATSA-ITP OSED version 3.0 sent to RFG members 5 August 2005– Commenters were asked to self select the priority of the comments (high, medium, low

or editorial)– Comments requested from RFG members by 9 September 2005– Received 313 comments on version 3.0– Majority of the comments were either “low” or “editorial”– Next version to be released within the next couple of weeks

ATSA-ITP Operational Hazard Assessment (OHA) workshop to be held at RFG/7

– Held October 2005 in Brussels, Belgium

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ATSA - ITP

Airborne Traffic Situational Awareness - In-Trail Procedures Procedure Development and Approval

Desire global acceptance and approval of new oceanic procedures

– Operators desire approved procedures that will be applicable in all oceanic domains

– Implies ICAO approval required

South Pacific ICAO Procedures Development and Approval

– NASA briefed the Informal South Pacific ATS Coordination Group (ISPACG) briefing in February 2005

– Very interested in supporting and approving the procedure in the South Pacific

North Atlantic ICAO Procedures Development and Approval

– NASA briefed North Atlantic Implementation Management Group (NATIMG) briefing in April 2005 and the North Atlantic Air Traffic Management Working Group (NAT ATMG) in September 2005

– NAT ATMG will use a portion of the OSED developed by the RFG as a starting point for the ICAO procedure development

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ATSA - ITP

Goal– Enable a 6 month operational flight trial of the proposed Oceanic ADS-B

In-Trail Procedures on partner revenue aircraft

Objectives – Assess economic and operational feasibility of ADS-B In-Trail Procedures

Better understand system costs (flight deck, ground automation,etc.) Assess predicted benefits of ADS-B ITP Gain operational experience with ASAS technologies

– Establish basis for global ADS-B ITP implementation Lessons learned and data obtained will be used to aid implementation globally

Participants/Location – Evaluating Oakland/SOPAC flight trial

Held preliminary flight trial meetings with potential partners – Interest level is very high

– All participants desire to begin this within the next 18 months

– Planning fall workshop

Oceanic ADS-B In-Trail Procedures (ITP) Proposed ADS-B ITP Flight Trials

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ATSA - ITPSummary

Airborne Traffic Situational Awareness - In-Trail Procedures

– Airborne ADS-B data and an onboard decision support system used to enable climbs and descents that are not possible within today’s separation standards

– Addresses limitations of the existing TCAS In-Trail Climb procedure

– Aircraft that choose to equip are able to perform these additional in-trail maneuvers and achieve more optimal altitudes

– Results in more efficient and predictable flight profiles which translates into fuel savings and greater payload capacity

– Design goals

Buy its way into the cockpit (voluntary operator participation)

Global interoperability (where adopted)

Possible growth path

Benefit for first to equip (without disincentive for non-equipped)

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ATSA - ITPBack Up Slides

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ATSA - ITP

Procedure description broken up into 4 phases

Initiation, Instruction, Execution, and Termination

Definitions and Terms are key to understanding the procedure

Airborne Traffic Situational Awareness - In-Trail ProceduresDetailed Procedures

ITPAircraft

ReferenceAircraft

RequestedFlightLevel

CurrentFlightLevel

InterveningFlightLevel

StandardLongitudinal

Separation Requirement

OtherAircraft

StandardLongitudinal

Separation Requirement

ITPCriteria

OtherAircraft

Potentially BlockingAircraft

OtherAircraft

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ATSA - ITP

Qualifications/Preconditions for Conducting the ITP– Airline operational specifications permit ITP– Flight crew of ITP aircraft is properly qualified for ITP maneuvers – ITP aircraft must:

Have ITP equipment, providing flight crew with flight ID, range and ground speed differential to potentially blocking aircraft

Have own-ship position data accuracy meeting requirement for ITP Be on a same track with potentially blocking aircraft

– Requested flight level shall be: One same direction flight level above/below one intervening flight level No more than 4000 feet above/below current flight level

ITP Initiation Criteria– Range and ground speed differential criteria are met, for example:

Range from ITP aircraft to reference aircraft is greater than 15NM, and Positive ground speed differential is less than +20 knots

– Reference aircraft has qualified ADS-B– ITP aircraft’s performance will enable a vertical speed of at least +/-300 fpm at assigned

Mach number to requested flight level

ITP Request– If ITP qualifications/preconditions and criteria are met, ITP aircraft crew requests ITP,

providing the controller with flight ID and range of reference aircraft

Airborne Traffic Situational Awareness - In-Trail ProceduresDetailed Procedures – ITP Initiation

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ATSA - ITP

Controller ITP Clearance Issuance– If safe longitudinal separation will be maintained, a standard flight level

change clearance may be granted, if not – Controller:

validates flight ID of Reference Aircraft determines there is no greater than +0.03 Mach difference verifies Reference Aircraft is not in the process of changing its flight level or

direction

– Based on the ITP Aircraft’s request and controller’s determination, the controller would grant ITP request

ITP Crew Re-Assessment – After ITP clearance is issued, ITP Aircraft crew must again determine

that ITP criteria are met immediately before initiating climb or descent

Airborne Traffic Situational Awareness - In-Trail ProceduresDetailed Procedures – ITP Instruction

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ATSA - ITP

During the ITP Maneuver Crew performance

– Crew must: initiate ITP without delay after receipt of clearance,

(no different than initiating a standard climb or descent clearance) strictly adhere to assigned Mach number during maneuver maintain a minimum +/-300 fpm vertical speed throughout maneuver

– ITP aircraft crew is not required to monitor the range to reference aircraft during climb or descent.

– ITP flight crew reports established at new flight level

Controller performance– After issuance of the ITP clearance, controller will:

protect ITP aircraft’s initial flight level until it reports established at new flight level (for non-normal case where ITP aircraft must return to initial flight level)

not issue any maneuver clearance to reference aircraft until ITP aircraft reports established at new flight level

Airborne Traffic Situational Awareness - In-Trail ProceduresDetailed Procedures – ITP Execution

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ATSA - ITP

ITP Termination– ITP is completed when ITP aircraft flight crew reports established

at new flight level– If ITP aircraft must return to its initial flight level, an abnormal

termination occurs

Airborne Traffic Situational Awareness - In-Trail ProceduresDetailed Procedures – ITP Termination

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ATSA - ITPTCAS In-Trail Climb/Descent Chronology

Trial procedure approved for use in Oakland and Anchorage FIRs– Only United and Delta approved for Phase 1 trials (10/94 – 3/96)

Both aircraft (the lead aircraft, and the one performing the ITC) had to be qualified Phase 1 ITC trials

– 68 ITCs requested and 37 ITCs performed in first 18 months of trial (10/94-3/96)

– Limited utility due to Both aircraft had to be participating (i.e. United and/or Delta) Limited TCAS range, unreliability of TCAS at longer ranges to reacquire traffic

when transponder cycled Subsequent Actions

– Rapidly fell out of favor, partially due to ALPA concerns– Airlines removed ITC procedures from their Aircraft Flight Manuals in 2000– United has put TCAS ITC back in their manuals in the Pacific, primarily as a

tool for turbulence avoidance Airline Pilots Association (ALPA) expressed concerns over the

procedure– Safety system cycled on and off– Lack of flight ID on display

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ATSA - ITP

0 1 2 3 4

Time(hrs)

290

300

310

320

330

340

350

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370

380

390

400

FL

(fe

et)

10º20º30º40º50º

Note: Data is for a Boeing 777-200B at Mach .84 with a track entry weight of 530,000 lbs. This is for a standard day with zero winds.

Approximate location for waypoint reporting points.

Operator Efficiency ConsiderationsFuel Burn Comparisons by Altitudes Flown

Boeing 777-200B(Eastbound in NATOTS)

∆ = 3148 lbs∆ = 3148 lbs∆ = 1022 lbs∆ = 1022 lbs

∆ = 835 lbs∆ = 835 lbs∆ = 2099 lbs∆ = 2099 lbs∆ = 3587 lbs∆ = 3587 lbs∆ = 5353 lbs∆ = 5353 lbs

∆ = 196 lbs∆ = 196 lbs

Minimum Burn Level Crossing (MBLC)

∆ ∆ = 0 lbs= 0 lbs∆ ∆ = 0 lbs= 0 lbs

∆∆= -112 lbs= -112 lbs∆∆= -112 lbs= -112 lbs

Unrestricted Altitude Crossing (UAC)Unrestricted Altitude Crossing (UAC)

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ATSA - ITP

Atlantic and Pacific Oceanic Regions and Route Structures

Fixed Routes (eg., CEP)– Fixed routes similar to domestic

airway structure– Do not account for changing

wind or weather conditions– Reduce complexity for ATC,

but are not always most efficient for customers

Organized Track Systems (eg., NATOTS, PACOTS)– Flexible track system established by ATSP’s, utilizing forecasted weather conditions to produce

the most time/fuel efficient routes for a representative city pair (established daily)

User Preferred Routes (UPRs)– Optimized routes generated by individual operators based on aircraft type, aircraft loading,

weather and flight plan requirements– Advantages include optimum cruise trajectories (altitudes, routes), improved fuel efficiency,

increased predictability on fuel usage and payload capacity

WATRS EUR-CAR

EUR-NAM

NATOTS

CEP

SOPAC

PACOTS

NOPAC

CENPAC