Airborne Traffic Situational Awareness

1

• Airborne Traffic Situational Awareness
• In-Trail Procedure (ATSA-ITP)
• Presented to the ASAS Thematic Network 2
• Malmo, Sweden
• September 27, 2005
• Stephane Marche
• Ken Jones
• Tom Graff

2
Outline

• Background
• Oceanic Challenges
• TCAS In-Trail Climb/Descent
• Airborne Traffic Situational Awareness In-Trail
  Procedure
• Overview
• Chronology of RFG activities
• Summary

3
North Atlantic Organized Track SystemOverview
and Technical Challenges

• 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

Solution
Optimal
Compromise
4
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)
• UPRs optimized routes generated by individual
  customers (preferred solution)
• Most UPRs 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

5
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

6
TCAS In-Trail Climb
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

• 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

7
Airborne Traffic Situational Awareness - In-Trail
Climb
FL360
FL350
FL340
blue ADS-B transceiver and onboard decision
support system red 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

8
Airborne Traffic Situational Awareness - In-Trail
Procedures

• 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

9
Airborne Traffic Situational Awareness - In-Trail
ProceduresIncreased Opportunities for Flight
Level Changes

• Restrictions based on todays procedures and
  standards
• Co-speed _at_ Mach .80 ? 10 minute separation, 80
  nm required
• No climbs allowed if other traffic are in the red
  hatched area

FL360
FL350
80 nm
-80 nm
FL340

• 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

FL360
FL350
15 nm
-15 nm
FL340
10
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
  airlines total annual fuel consumption!

• 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

11
Airborne Traffic Situational Awareness - In-Trail
ProceduresDetailed concept of operations

• 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

12
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

13
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

14
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

15
Oceanic ADS-B In-Trail Procedures (ITP) Proposed
ADS-B ITP Flight Trials

• 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

16
Summary

• 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 todays 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)

17
Back Up Slides
18
Airborne Traffic Situational Awareness - In-Trail
ProceduresDetailed Procedures

• Procedure description broken up into 4 phases
• Initiation, Instruction, Execution, and
  Termination
• Definitions and Terms are key to understanding
  the procedure

Requested Flight Level
Reference Aircraft
Intervening Flight Level
ITP Aircraft
Current Flight Level
Standard Longitudinal Separation Requirement
Standard Longitudinal Separation Requirement
19
Airborne Traffic Situational Awareness - In-Trail
ProceduresDetailed Procedures ITP Initiation

• 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 aircrafts performance will enable a vertical
  speed of at least /-300 fpm at assigned Mach
  number to requested flight level
• ITP Request

20
Airborne Traffic Situational Awareness - In-Trail
ProceduresDetailed Procedures ITP Instruction

• 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 Aircrafts request and
  controllers 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

21
Airborne Traffic Situational Awareness - In-Trail
ProceduresDetailed Procedures ITP Execution

• 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 aircrafts 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

22
Airborne Traffic Situational Awareness - In-Trail
ProceduresDetailed Procedures ITP Termination

• 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

23
TCAS 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

24
Operator Efficiency ConsiderationsFuel Burn
Comparisons by Altitudes Flown
Boeing 777-200B (Eastbound in NATOTS)
25
Atlantic and Pacific Oceanic Regions and Route
Structures
NATOTS
NOPAC

• 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 ATSPs,
  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

EUR-NAM
PACOTS
WATRS
CENPAC
EUR-CAR
CEP
SOPAC