B.5.9 WP95

Review Continuous Descent Operations

Manual

Presented by:Bill Holtzman (USA)

Roosevelt Pena (Dom Rep)on behalf of TOC

B.5.9 CDO WP95

FAA Administrator

Note: This video from February 8, 2011 was shown at the Amman Conference but is not available for distribution.

B.5.9 CDO WP95

Current Operations

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Continuous Descent

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IATA

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Doc 9931

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Continuous Descent Operations (CDO) is an aircraft operating technique aided by appropriate airspace and procedure design and appropriate air traffic control (ATC) clearances enabling the execution of a flight profile optimized to the operating capability of the aircraft, with low engine thrust settings and, where possible, a low drag configuration, thereby reducing fuel burn and emissions during descent.

Doc 9931 Definition

B.5.9 CDO WP95

• “Continuous Descent Operations” (CDO) is a class of procedures.

• “Continuous Descent Approach” (CDA) is a procedure.

• “Optimized Profile Descent” (OPD) is a procedure. This term is used in the USA.

Terminology

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CDAs in the UK

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• First published OPD in the US, the River One STAR - 2007

• Average savings - 25 gallons a flight for 300-400 daily

• Fifth busiest US airport with 545,000 operations in 2009

• 40+% of LAX approaches now OPDs

Los Angeles Intl (LAX)

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RIIVR2

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RIIVR2 Profile

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RIIVR2 to ILS

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1. Use active controllers2. Obtain data on typical trajectories3. Apply the “90%” rule4. Build an initial CDA

The LA Way

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5. Break trajectory into segments6. Use a trajectory simulation tool7. Redesign the associated sectors8. Perform simulation testing9. Begin implementation

The LA Way

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Critical elements• Precisely spaced arrival flow• Automated wind information• “90% rule”• Design to hit merge points• Lots of simulationNot necessary• Dynamic resectorization

US Lessons Learned

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Manual identifies two goals:• Continuous descent• Increased flight predictabilityTo the controller, predictability is:• Restricted trajectory - single 3D path• “Low tolerance” CDATo the pilot:• Unrestricted trajectory• “High tolerance” CDA

Doc 9931 - Predictability

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Trajectories

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90% Envelope

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1.2.1.5.2 - The open path design is a design where a portion, or all, of the route consists of vectoring. The specific distance to runway threshold is not known prior to start of the CDA.

Two procedures:• Vectored CDA• Open CDA to Downwind

Open Path

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Open CDA to Downwind

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1.2.1.5.1.1 - The closed path design is a design where the route is fixed and the specific distance to the runway is known prior to start of the continuous descent operation. The procedure may be published with crossing levels, level windows and/or speed constraints. The design of the closed path may comprise the STAR and (initial) approach phases of flight until the FAF/FAP final approach point (FAP).

Closed Path

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Path Stretching

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Merge Points

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• On demand, individually constructed route and profile clearance

• Transmitted via data link from Ocean21 system to FANS-1/A aircraft

• 6 years of testing in Australia, Netherlands and US

• Operational in San Francisco, Los Angeles, Miami this year

• Fuel savings – 75-400 gallons per arrival (280-1500 L)

Tailored Arrivals (TA)

B.5.9 CDO

1. The CDO Manual incorrectly uses the term “CDO” to refer to a procedure.

2. The ICAO definition of CDO only considers the perspective of a single aircraft.

3. Flight predictability should be increased for both the aircraft and the ATM system.

4. Best practices for CDA design should be derived from successful implementations.

5. Open Path CDAs are a compromise between predictability and controller flexibility.

6. Restricting the controller’s ability to intervene reduces ATM capacity.

Conclusions

B.5.9 CDO

7. In CDA design, there is a trade-off between capacity and the aircraft’s optimal flight path. • “Low tolerance” CDA

Higher predictability for controller Higher capacity for non-arrival traffic Inhibits ideal engine-idle trajectories

• “High tolerance” CDA Lower predictability for controller Lower capacity for non-arrival traffic Pilots fly ideal descent trajectories

Conclusions

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Debate

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4.1 - IFATCA Policy is:

IFATCA defines Continuous Descent Operations as:Continuous Descent Operations (CDO) are aircraft operating techniques facilitated by appropriate airspace and procedure design which meet all ATM requirements, allowing the execution of an optimized descent profile.and is included in the IFATCA Technical and Professional Manual.

Recommendations

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Recommendations

4.2 – IFATCA Policy is:IFATCA supports the development and implementation of Continuous Descent Operations provided that:• Controllers are involved in the design.• Airspace is suited to the design.• The design meets the desired ATM capacity.• Tactical ATC interventions are allowed.• Flight predictability is increased for both pilots

and controllers.• Controller workload is not increased beyond an

acceptable level.

and is included in the IFATCA Technical and Professional Manual.

B.5.9 CDO WP95

Recommendations

4.3 - IFATCA Policy is:Doc 9931 should be amended as follows:• Incorporate CDA design practices learned by

the pioneers of continuous descent, including the 90% rule, the use of extensive simulation and the need for automated wind data and advanced sequencing tools.

• More precisely refer to those procedures it aims to regulate as either Continuous Descent Arrivals (CDAs) or Optimized Profile Descents (OPDs).

and is included in the IFATCA Technical and Professional Manual.