Oceanic ITP Airborne Traffic Situational Airborne Traffic Situational Awareness Awareness – – In-Trail Procedure (ATSA-ITP) In-Trail Procedure (ATSA-ITP) Presented to the ASAS Thematic Presented to the ASAS Thematic Network 2 Network 2 Malmo, Sweden Malmo, Sweden September 27, 2005 September 27, 2005 Stephane Marche Stephane Marche Ken Jones Ken Jones Tom Graff Tom Graff
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Oceanic ITP Airborne Traffic Situational Awareness – In-Trail Procedure (ATSA-ITP) Presented to the ASAS Thematic Network 2 Malmo, Sweden September 27,
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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
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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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+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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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)
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
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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
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
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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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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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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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
– 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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Procedure description broken up into 4 phases
Initiation, Instruction, Execution, and Termination
Definitions and Terms are key to understanding the procedure
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
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
– 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
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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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