Cold Weather Ops by Airbus

Cold Weather OperationsImpact on the Fuel System and Dispatch

Presented by

Zidan RENFlight Operations Engineer

OLM FBW 2006 – Toulouse – 26-28 September 2006

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Cold Weather Operations: Impact on the Fuel System and Dispatch 3 OLM FBW 2006

Fuel and Fuel System CharacteristicsFuel and Fuel System Characteristics

Contents

1

2 Dispatch Consideration

3 On Ground and In Flight Procedures

4 Conclusion

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Fuel and Fuel System Characteristics

The Fuel System will trigger low temperature alerts when thefuel in the tanks is colder than certain temperature thresholds.

The low temperature thresholds are defined with theconsideration of:

Fuel freezing point;

Engine margin;

Overall temperature accuracy error.

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Fuel Freezing PointFuel Freezing Point

ASTM International standard:The temperature at which thewax crystals in the fuel,formed previously when thefuel was cooled, completelydisappear when the fuel iswarmed.

Fuel Freezing PointSpecification values

Fuel Freezing PointSpecification values

JetA

JP5

JetA1 / JP8

TS-1 / RT

JetB

TH

JP4

–40 °C

–46 °C

–47 °C

–50 °C

–50 °C

–53 °C

–58 °C

JetA –40 °C

JetA1 / JP8 –47 °C

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Fuel Freezing PointFuel Freezing Point

Mixed fuel:

Experiments have shown that fuel mixtures do not behave asideal fluids; the resulting freezing point is commonly adverselyaffected.

A common practice* to evaluate JetA/JetA1 mixtures:

* Not an approved method

– JetA less than 10% in the mixture:

JetA1JetA1>90%>90%

JetAJetA

Fuel Freezing Point:

JetA1JetA1

– JetA more than 10% in the mixture:

JetA1JetA1 JetAJetA>10%>10%

Fuel Freezing Point:

JetAJetA

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Engine MarginEngine Margin

The temperature marginthat ensures the requiredfuel viscosity at engine inlet.

Different engine systemarchitectures lead todifferent temperaturemargins over the fuelfreezing point.

Engine MarginEngine Margin

PW

RR

GE

IAE

CFM - A320F

CFM - A340

0 °C

0 °C

3 °C

4 °C

4 °C

5 °C

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Fuel SystemFuel SystemA318/A319/A320/A321 A330/A340

Short- to medium-haul flights. Less exposed to extremely cold atmosphere.

Fuel recirculation system – IDG oil cooling.Warmed fuel from engine returns to the outer (wing) tank.

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Fuel Low Temperaturealert thresholds: Advisory: –40°C

Caution: –45°C

-40 °C -38 -38 °C -40

TAT –42 °C GW KGSAT –67 °C 05H20

A318/A319/A320 System Display - FUEL

-40 °C -38 -38 °C -40



-40 °C -38 -38 °C -40



-40 °C -38 -38 °C -40



FUEL L WING TK LO TEMP< R WING >

A321 Engine/Warning Display

FUEL L OUTER TK LO TEMP< R OUTER >< L INNER >< R INNER >

A318/A319/A320 Engine/Warning Display

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Long-haul flights.

No fuel movementin the outer tanksbefore thetransfer tothe innertanks.Outer tanks

are moreprone to lowtemperaturealerts.

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Alert thresholds

JetAFreezing Point(Specification)

–40°C

JetAFreezing Point(Specification)

–40°C

Inner TanksEngine margin

Outer Tanks& Trim Tank

No engine margin



No engine margin

A330

A340 -200-300

A340 -500-600

GE 3°C

CFM 5°C

RR 0°C

First trigger of theECAM caution: FUEL FUEL LO TEMP

A330/A340 Engine/Warning Display

A330A330A330Inner Outer/Trim–37°C –40°C

A340-200/-300A340A340--200/200/--300300Inner Outer/Trim–35°C –40°C


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Alert thresholds

JetA1Freezing Point(Specification)

–47°C

JetA1Freezing Point(Specification)

–47°C



No engine margin



No engine margin

A330

A340 -200-300

A340 -500-600

GE 3°C

CFM 5°C

RR 0°C

Recall of theECAM caution: FUEL FUEL LO TEMP

A330/A340 Engine/Warning Display

A330A330A330Inner Outer/Trim–44°C –47°C



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Influencing Factors of Fuel TemperatureInfluencing Factors of Fuel Temperature

Initial fuel temperature

Outside Air Temperature

Mach number

Fuel quantity (tank full / not full)

Size and shape of the fuel tank

Day flight / night flight (solar heat)

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Contents

1



4 Conclusion

Dispatch Consideration

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Flight PlanningFlight Planning

FTP – Fuel Temperature Prediction software

Part of Airbus’ performance programs package WinPEP

Accurate prediction of fuel temperature in each tank

Takes into account actual weather

Interfaces with airline flight planning system

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Flight PlanningFlight Planning

FTP – Fuel Temperature Prediction software

SUMMARY OF OUTPUTNO FUEL FREEZING ISSUES ENCOUNTEREDNORMAL FUEL MANAGEMENTMINIMUM OAT OF -68 OCCURRED AT WAYPOINT GOPTA

MINIMUM TEMPERATURES OF ALL TANKSTANK TEMPERATURE WAYPOINTL_OTR -37 BDINR_1 -34 BUINR_2 -31 YBLCT -30 BRTINR_3 -32 YBLINR_4 -34 BUR_OTR -37 BURCT -31 AGEMATT -35 KENTA

SUMMARY OF OUTPUTNO FUEL FREEZING ISSUES ENCOUNTEREDNORMAL FUEL MANAGEMENTMINIMUM OAT OF -68 OCCURRED AT WAYPOINT GOPTA

MINIMUM TEMPERATURES OF ALL TANKSTANK TEMPERATURE WAYPOINTL_OTR -37 BDINR_1 -34 BUINR_2 -31 YBLCT -30 BRTINR_3 -32 YBLINR_4 -34 BUR_OTR -37 BURCT -31 AGEMATT -35 KENTA

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Actual Fuel Freezing PointActual Fuel Freezing Point

Knowing the actual freezing point of the fuel loaded on theaircraft may allow the flight crew to delay the fuel lowtemperature procedures.

May be determined by means of a fuel freeze analysisprogram

Provided a monitoring program,including maintenance, dispatch,and flight crew procedures, hasbeen set up and accepted by theauthorities.

Jet Fuel QualityAnalyzer

Jet Fuel QualityAnalyzer

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Actual Fuel Freezing PointActual Fuel Freezing Point

Operators that often face low fuel temperature situations areencouraged to determine the fuel’s actual freezing point beforethe flight.

Example:Based on a survey at several major US airports over a givenperiod of time, the measured freezing point of JetA fuel is 3°C(conservative average) lower than the specification value.

JetA Freezing Point Average Range

New York –45.2°C –44.1°C ~ –46.0°C

Los Angeles –50.9°C –46.8°C ~ –58.2°C

Chicago –43.2°C –42.4°C ~ –44.7°C

San Francisco –52.2°C –48.6°C ~ –56.1°C

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Contents

1



4 Conclusion

On Ground and In Flight Procedures

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Advisory and/or caution will be triggered on the ECAMwhen the temperature in the tanks drops below thedefined threshold.

Application of the ECAM procedure can be delayedconsidering:

The actual fuel type;

The actual freezing point measured prior to the flight.

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Before TakeBefore Take--offoff

All Aircraft Types

FUEL <...> LO TEMP-DELAY T.O

Engine/Warning DisplayIf the fuel low temperaturecaution is triggered beforethe flight, the take-offshall be delayed until alltemperatures are withinthe limits.

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In FlightIn Flight

A318/A319/A320/A321 A330/A340-200/-300 A340-500/-600

FUEL L WING TK LO TEMP< R WING >

A321 Engine/Warning Display

FUEL L OUTER TK LO TEMP< R OUTER >< L INNER >< R INNER >

A318/A319/A320 Engine/Warning Display Caution is triggered forcrew awareness

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In FlightIn Flight

A318/A319/A320/A321 A330/A340

Principle of the fuel low temperatureprocedures:Outer tank low temperature:

– Outer to inner transfer.

Inner tank low temperature:– Center to inner transfer.

Trim tank low temperature:– Trim tank transfer forward.

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In FlightIn Flight

A318/A319/A320/A321 A330/A340-200/-300 A340-500/-600

FUEL FUEL LO TEMP∙IF JET A FUEL:

-OUTR TK XFR.........ON∙IF NECESSARY:

-TAT...........INCREASE

A330 (FWC K8) and A340-200/-300 (FWC L10) EWD

∙IF JET A FUEL:-CTR TANK XFR.......MAN

∙IF JET A FUEL:-T TANK MODE........FWD

First trigger of the ECAMcaution – Application of procedure

can be delayed if:– Fuel onboard is not JetA;

(fuel with lower freezing point)

or

– Actual freezing point islower than –40°C.

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In FlightIn Flight

A318/A319/A320/A321 A330/A340-200/-300 A340-500/-600

FUEL FUEL LO TEMP-OUTR TK XFR.........ON

∙IF NECESSARY:-TAT...........INCREASE

A330 (FWC K8) and A340-200/-300 (FWC L10) EWD

-CTR TANK XFR.......MAN

-T TANK MODE........FWD

Recall of the ECAMcaution – Application of procedure

can be further delayed if:– Actual freezing point is

lower than –47°C.

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In FlightIn Flight

A318/A319/A320/A321 A330/A340-200/-300 A340-500/-600

FUEL LO TEMP-FUEL FREEZE PT...CHECK

∙IF JET A FUEL:MAX SPEED.........305KT-OUTR TK XFR........MAN


A340-500/-600 (FWC W4) Engine/Warning Display

∙IF JET A FUEL:-CTR TO INR XFR.....MAN

∙IF JET A FUEL:-T TK XFR...........FWD

First trigger of the ECAMcaution – Application of procedure

can be delayed if:– Fuel onboard is not JetA;

(fuel with lower freezing point)

or

– Actual freezing point islower than –40°C.

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In FlightIn Flight

A318/A319/A320/A321 A330/A340-200/-300 A340-500/-600

FUEL LO TEMP-FUEL FREEZE PT...CHECKMAX SPEED.........305KT-OUTR TK XFR........MAN


A340-500/-600 (FWC W4) Engine/Warning Display

-CTR TO INR XFR.....MAN

-T TK XFR...........FWD

Recall of the ECAMcaution – Application of procedure

can be further delayed if:– Actual freezing point is

lower than –47°C.

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After LandingAfter Landing

A318/A319/A320/A321 A330/A340

To benefit the subsequent flight, a manual fuel transfer fromouter to inner tanks may be performed just after landing, if ithas not been done during the last flight.

Considerations shall be based on:

Wing surface icingbefore the next take-off

FUEL LO TEMP cautionduring the subsequent flight

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A318/A319/A320/A321 A330/A340

Manual transfer after landing:

Ensures a better mix of the cooled reserve fuel with the warmerrefueling truck fuel.

Reduces exposure to condensation frost on wing surfaces.

No manual transfer after landing:

Keeps normal wing load for the subsequent flight, if no refuelingis planned at this airport.

Keeps the fuel with lower freezing point in the outer tanks forthe subsequent flight.

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A318/A319/A320/A321 A330/A340

Wing surface icing consideration: The worst scenario is a short transit at a “warm” humid airport

(no de-icing equipment).

Refuelingplanned at this

airport?


airport?

No Yes

No manualouter to inner

transfer


transfer

Manualouter to inner

transfer


transfer

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A318/A319/A320/A321 A330/A340

FUEL LO TEMP consideration for the subsequent flight:


airport?


airport?

Refuelingfuel is JetA or

JetA1

Refuelingfuel is JetA or

JetA1

Outer tanksare completely full with

JetA1 fuel

Outer tanksare completely full with

JetA1 fuel

No Yes

JetA JetA1

Yes No


transfer


transfer


transfer


transfer

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Contents

1



4 ConclusionConclusion

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Fuel low temperature alerts may be encountered on long-haul flights in extremely cold atmosphere. Outer tanks onLong Range aircraft are the most affected.

Software tool is available for predictive flight planning whenoperating cold weather routes.

ECAM procedures can be delayed if the actual fuelfreezing point measured before the flight is lower than thespecification value.

Selective manual fuel transfer from the outer to the innerwing tanks after landing may benefit the subsequent flightin cold atmosphere.

Conclusion

Documents

Cold Weather Ops by Airbus