Green Approaches: 4DTrajectory Enabled Continuous Descent Approaches

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Green Approaches4D-Trajectory Enabled
Continuous Descent Approaches

• Keith Wichman -- Smiths Aerospace
• FAA New Technologies Workshop III
• 9-10 January 2007, Arlington Virginia

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Example Aircraft capability
Thrust
Thrust

• Entire descent approach
• Least possible thrust
• Highest possible altitude

Todays std practice 610 step downs
Why are A-CDAs not much practiced?
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Why are CDAs not used wholesale?

• Myth CDAs reduce capacity
• Idle descent vertical and time profiles can vary
  widely from aircraft to aircraft
• This uncertainty drives need for ATC to block
  large chunks of airspace
• Thus, CDAs practiced today generally off-peak
  hours and/or sub-optimal descents
  (least-common-denominator fixed vertical
  profiles)
• Solution Marriage with 4D-trajectory downlink,
  and if needed, onboard time-guidance (RTA)
  functionality supplies ATC with observability and
  predictability to use CDAs during dense
  operations
• Requirements
• Aircraft 4D FMSs already predict reliable 4D
  Trajectories (4DT) and guide to Required Times of
  Arrival. Need appropriate downlink of the 4DT
• ANSP Operational shift toward Trajectory Based
  Operations (TBO) to incorporate the 4DT and the
  development of necessary support applications

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Trajectory-Based Operations

• Basis for strategic planning and tactical
  operations including separation management.
• Key concept element for the USAs NGATS and
  Europes SESAR
• Four-dimensional trajectory (4DT) is the
  cornerstone of Trajectory-Based Operations for
  improved predictability
• Open-ended flight maneuvers (such as vectoring)
  reduce predictability.
• Closed trajectory-based maneuvers improve
  predictability.
• While designed to optimize an individual flight
  and reduce pilot workload, modern FMSs offer
  much capability that could be tapped by ATM to
  optimize the whole system. Trajectory-based
  operations seeks to exploit this functionality.

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The Paradigm Shift
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Roadmap

• NGATS and SESAR aim to set vision and path to
  achieve 4DT ATM
• In-service operational evaluations represent
  forays into the future
• Validation of concepts
• Validation of benefits
• Results and data informs decisions of political
  activities (NGATS, SESAR)
• These vanguard activities require effective
  teaming across domains
• ANSP (and equipment suppliers)
• Operators (and OEM suppliers)
• Airport Authority
• basis for the integrated system seen by NGATS
  and SESAR.
• The European Commissions NUP2 Program is
  presented here.

Triplets
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Terminal Movements with Trajectory-Based
Operations

• Increased arrival/departure throughput and
  efficiency.
• Increased predictability
• Reduced track distances
• Reduced voice communications vectoring
• More efficient vertical profiles with reduced
  fuel consumption.

Metering Fix
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FMS and Avionics
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Required Time of Arrival

• Algorithm is based on speed variation.
• Fixed lateral path
• Fixed cruise altitude
• Required Time of Arrival is enabled for any point
  in the flight plan.
• Available on 737 aircraft since 1986.
• Demonstrated performance in trials with SAS in
  2001.
• Future enhancements
• Improved control to the runway accounting for
  fixed speed segments.
• Compensation for control error tolerance when
  reporting trajectory early in the flight.
• Include lateral offset and/or cruise altitude
  variation when additional delay is required.

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RTA to the Runway

• Results were obtained in trials with SAS in 2001
  (33 flights).
• Performance is better when controlling to start
  of arrival due to more speed-control authority.
• Limited control late in descent due to
  constrained speed.

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Intent Bus in B737 U10.6 FMS
Current A/C State and Trajectory Predictions
First application in 2005 Provide FMS 4D
trajectory to ATC!

• ARINC 702A-1 Trajectory Bus
• Aircraft current-state information 2Hz
• Aircraft 4D trajectory predictions (Intent)
• Each minute or when FP changes
• Full trajectory to runway
• Includes vertical wpts and turns
• Dedicated ARINC 429 Bus
• As per ARINC702A-1

ARINC429 Trajectory Bus
ACARS
in 2007!

• ACARS messages added for interim use in flight
  trials
• By REQ from ATC
• One-time or periodic downlink

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ARINC 702A-1 4DT Data for Stockholm to Malmo
Flight
Route ESSAESMS10 ---------starts
here----------- 1,,,N59397E017581. 1,R,113,N59401E
018009,108,090122. C,,,N59376E018019,500,090227. 0
,R,557,N59359E017585,769,090306. 0,L,934,N59302E01
7443,1279,090456. 0,,,N59070E017184,2511,090907. 0
,R,1893,N59044E017155,2604,090932. B,,,N58515E0165
48,3032,091149. 8,,,N58380E016335,3500,091408. 0,,
,N58366E016312,3500,091423. 0,,,N57592E015342,3500
,092051. 0,,,N57388E015041,3500,092420. 0,,,N57024
E014122,3500,093032. 0,,,N56455E013489,3500,093323
. 9,,,N56354E013354,3500,093504. 0,L,981,N56345E01
3340,3450,093513. B,,,N56295E013331,3223,093553. 0
,L,1249,N55550E013268,2010,094058. 1,R,406,N55247E
013335,1002,094623. 1,R,215,N55210E013322,886,0947
12. C,,,N55189E013229,500,094951. 0,L,171,N55198E0
13275,459,095034. 0,,,N55276E013235,148,095357. 0,
,,N55314E013227,29,095528. 1,,,N55329E01321200002
926 EOT finalLDU1, CRC3483
0,L,934,N59302E017443,1279,090456
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NUP 2 Partners
ANS
Airlines
Airports
Industrial group
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NUP2 Trajectory Usage
Flight operations began January 19th, 2006
ACARS ARINC 702A-1 standard
AOC SAS RC Hermes
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Trajectory Reporting

• ARINC 702A Supplement 1 was defined for early
  implementation.
• Implemented in 737 FMS with U10.6 software
  dedicated ARINC 429 bus.
• ACARS downlink of trajectory intent information
  as interim datalink.
• European Commission (EC) supported activity,
  NUP2, in Sweden and Austria.
• Operational evaluations began in October 2005
  including
• RTA contracting to the runway.
• Green Approaches (CDAs) with FMS 4D trajectory to
  preserve capacity.
• Slot Swapping
• Ground Holding
• First air/ground operation connectivity of FMS
  4DT with Arrival Manager
• Airlines are deriving demonstrable benefits
  (punctuality, fuel).
• Operations now in medium traffic conditions
  moving toward peak traffic.

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First 4D FMS Trajectory Downlink
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Controlled Time of Arrival

• Generated by a Time-Based Metering system to
  merge traffic from metering fixes to a runway.
• A key capability of an FMS is to self-deliver
  to a specified waypoint at a Required Time of
  Arrival (RTA).
• The FMS efficiently operates a flight with a user
  selected Cost Index (CI) and a Continuous Descent
  Approach (CDA).
• Accurate ETAs need to be downlinked from the
  aircraft to close the loop with ground control.

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ANSP Integration of 4DT in Arrival Management
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Strategic Communication Description
Climb
Descent
En-route
Lift-Off
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Example from live trial
Reply RTA unachievable
RTA Accepted
In the new downlinked 4DT messages, the time
separation at HMR had increased from 1 to 2
minutes
Via 4DT downlink SAS075 confirms GA HAMMAR1V with
ETA 0649
RTA Accepted
Via 4DT downlink SAS2059 confirms GA HAMMAR1V
with ETA 0650
Controller want 180 second separation. Send RTA
064700 to SAS075
Sends RTA 064800 to SAS075 and RTA 065100 to
SAS2059
Controlling to time resulted in physical
separation of 10NM at OM
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Benefits of the 4DT Approach
1st 4DT downlink 19th of October 2005 1st 4DT
Flight 19th of January 2006 General 4DT operation
from 26th of March 2006
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NUP 2 ResultsFuel Savings CDA vs Standard
Approach
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TRANSCAP Noise results
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Next step Arlanda Mixed mode operation
160kts OM
10NM
5NM
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Next step Arlanda Mixed mode operation
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SAS Sweden Experience from 800 Green Approaches

• More than 650 Green Approaches flown to date
  (and counting) resulted in
• 204 Metric Ton CO2 reduction yearly
• 715 kg of NOx reduction yearly
• 130,000 kg of fuel saved
• SAS-Sweden 36,000 Green Approaches per year into
  Stockholm alone
• 5.8M fuel reduction yearly
• 23,000 Metric Ton CO2 reduction yearly
• 79 Metric Ton of NOx reduction yearly
• Large noise reductions (being quantified)
•  
• SAS and LFV expanding Green Approaches throughout
  domestic Sweden
•  

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NUP2 Steps for 2007

• Install VMMR to downlink 4DT via ADS-B
• Install EFBs for surface movement guidance
  operations
• Install enhanced FMS software for better
  predictions and RTA
• Conduct controller simulations with mixed
  equipage and high traffic
• Operate regularly in peak traffic (gt57 mvts/hr),
  mixed equipage, CDAs and validate capacity
  unchanged or increased.
• Infuse results into JPDO-NGATS and SESAR
• Also
• Plans firming to expand the operations in 2007 to
  adjacent regions in core-Europe in order to
  begin developing end-end benefits to
  participating airline operations.