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Safety FirstThe Airbus Safety Magazine

# 04 June 2007

Dear Customers and Aviation Safety colleagues,

It is not a secret that Airbus has encountered someturbulence as you have undoubtedly seen in thepress.

Despite this challenging period of time, I hope this4th issue of our Safety Magazine will reassure youthat Flight Safety remains as one of our primeCorporate priorities.

Let me take the opportunity of this 4th issue ofSafety First to share with you the Safety Vision atAirbus that our President and CEO Mr LouisGallois - delivered to all Airbus employees:

Hundreds of millions of people fly on Airbusaircraft every year, and their safety must beforemost in our minds and actions. We will needto be flexible, adaptable and creative in meetingthe multiple challenges our company faces, butwe must never compromise when it comes toquestions of safety. It is our highest duty, and asyour CEO, I promise to do my part, and expecteach of you to do the same.

As another commitment to Safety, our customershave received an invitation for our annual FlightSafety Conference. Refer to the News chapter thatfollows for more information.

I hope you will enjoy reading this 4th issue andshare it within your airline.

Yours sincerely

Yannick MALINGEVice President Flight Safety

Yannick MALINGE

Vice President Flight Safety

Editorial# 04 June 2007

ContentThe Airbus Safety Magazine . . . . . . . . . 1NewsC. Courtenay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Operations Engineering Bulletin reminder functionL. Boselli . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Avoiding high speed rejected takeoffsdue to EGT limit exceedanceA. Bonnet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Do you know your ATC/TCAS panel ?B. Vignault . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Managing hailstormsA. Urdiroz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18Introducing the Maintenance Briefing NotesU. Eggerling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22A320 - Dual hydraulic lossM. Palomque . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Terrain Awareness and Warning Systemsoperations based on GPS dataD. Cartensen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28Airbus Flight SafetyContacts/Organisation . . . . . . . . . . . . . . . . . . . 32

1

Safety First# 04 June 2007

Safety First is published by Airbus S.A.S1, rond point Maurice Bellonte31707 Blagnac Cedex / France

Editors:Yannick Malinge, Vice President Flight SafetyChristopher Courtenay, Director of Flight Safety

Concept Design byHCSGM 20070592Production by Quatcoul

Copyright: GSE

Photos copyright Airbus Photos by ExM: Herv BerengerPhilippe MascletHerv Gouss

Printed in France

Airbus S.A.S. 2007 All rights reserved. Confidential and proprietary documents.

By taking delivery of this Brochure (hereafter Brochure), you accept on behalf of yourcompany to comply with the following guidelines:

No other intellectual property rights are granted by the delivery of this Brochure than theright to read it, for the sole purpose of information.

This Brochure and its content shall not be modified and its illustrations and photos shallnot be reproduced without prior written consent of Airbus.

This Brochure and the materials it contains shall not, in whole or in part, be sold, rented, or licensed to any third party subject to payment.

This Brochure contains sensitive information that is correct at the time of going to press. This information involves a number of factors that could change over time, effecting thetrue public representation. Airbus assumes no obligation to update any information containedin this document or with respect to the information described herein.

Airbus SAS shall assume no liability for any damage in connection with the use of thisBrochure and of the materials it contains, even if Airbus SAS has been advised of thelikelihood of such damages.

Safety FirstThe Airbus Safety MagazineFor the enhancement of safe flight through increased knowledge and communications.

Safety First is published by the Flight Safety Departmentof Airbus. It is a source of specialist safety informationfor the restricted use of flight and ground crew memberswho fly and maintain Airbus aircraft. It is also distributedto other selected organisations.

Material for publication is obtained from multiple sourcesand includes selected information from the Airbus FlightSafety Confidential Reporting System, incident andaccident investigation reports, system tests and flighttests. Material is also obtained from sources within theairline industry, studies and reports from governmentagencies and other aviation sources.

All articles in Safety First are presented for informationonly and are not intended to replace ICAO guidelines,standards or recommended practices, operator-mandated

requirements or technical orders. The contents do notsupersede any requirements mandated by the State ofRegistry of the Operators aircraft or supersede or amendany Airbus type-specific AFM, AMM, FCOM, MELdocumentation or any other approved documentation.

Articles may be reprinted without permission, except wherecopyright source is indicated, but with acknowledgementto Airbus. Where Airbus is not the author, the contents ofthe article do not necessarily reflect the views of Airbus,neither do they indicate Company policy.

Contributions, comment and feedback are welcome. Fortechnical reasons the editors may be required to make editorialchanges to manuscripts, however every effort will be madeto preserve the intended meaning of the original. Enquiriesrelated to this publication should be addressed to:

AirbusFlight Safety Department (GSE)1, rond point Maurice Bellonte31707 Blagnac Cedex - FranceE.mail: [email protected]: +33 (0)5 61 93 44 29


# 04 June 2007

14th Flight SafetyConference

The planning for this years conference is wellunderway. It will be held from the 15th to 18th Octoberin Barcelona. A provisional agenda has been definedand the invitations are being sent out in June. Ifyou are an Airbus customer, have not yet receivedan invitation and you would like one then pleasecontact Nuria Soler at the addresses below. Notethat this is a conference for Airbus and ourcustomers only. We do not accept outside partiesinto the conference so as to ensure that we canhave an open as possible forum for everybody toshare information.

As always we welcome presentations from you.The conference is a forum for everybody to shareinformation, so if you have something you believewill benefit other operators and/or Airbus thencontact us.

We always look forward to the conference so thatas well as sharing information in the conferenceitself we can all meet and talk on an informal basis.

News

2

Your articlesAs already said this magazine is a tool to help shareinformation. Therefore we rely on your inputs. Weare still looking for articles from operators that wecan help pass to other operators through themagazine.If you have any inputs then please contact us.

Contact: Chris Courtenay [email protected]: +33 (0) 562110284Mobile: +33 (0) 616036422

DistributionIf you have any questions about the distribution ofthe magazine either electronically or in hard copythen please contact us. Please use the proformaformat that you will find towards the back of themagazine. Send the complete information to thee-mail address or fax below.

Contact: Mrs Nuria Solere-mail: [email protected]: +33 (0) 561934429

1 IntroductionThe OEB reminder function provides help to theflight crew by enabling them to clearly identify theECAM messages affected by an OEB.Airbus strongly supports the use of this device sinceit reduces the flight crew workload, decreases thepossibility to forget an OEB procedure and keepsthe flight crew confidence in the ECAM. This articleintends to further promote this function and its use.

2 OperationsEngineering Bulletin

Operations Engineering Bulletins are issued byAirbus in parallel to the FCOM / QRH in order toprovide temporary operational procedures thataddress any deviation, from initial design objectives,having an operational impact. OEB proceduresare recommended by Airbus, and should befollowed immediately.

There are two types of OEBs, distinguished bytheir RED or WHITE color code.

RED OEBsare issued to highlight procedures having asignificant impact on the aircraft airworthiness andare subject to an Airworthiness Directive.Red OEBs are included in the FCOM Volume 3,and a copy of their procedure is copied in the QRHOEB chapter.

WHITE OEBs are issued to highlight information or procedureshaving an impact on the aircraft airworthiness.White OEBs are included in FCOM Volume 3. Ifthe OEB procedure is a deviation to ECAM, theOEB procedure is also copied in the QRH OEBchapter.

During the preliminary cockpit preparation, theflight crew must review all OEBs applicable to theaircraft. It must pay a particular attention to thered OEBs, and more particularly to the red OEBsthat override an ECAM procedure.

Note: Airbus is currently working on a new QRHList of Effective OEB (LEOEB) layout thatwill provide our operators with the list of allapplicable OEB versus their color and theirimpact on ECAM, if any (for additionalinformation, please refer to the OperationsLiaison Meeting 2006 presentation).

OperationsEngineeringBulletin reminderfunction

By: Ludovic BOSELLIFlight Operations Engineer

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The Airbus Safety Magazine

# 04 June 2007

3 OperationsEngineering Bulletinreminder function

The Flight Warning Computer (FWC) OEB reminderfunction is implemented to enable the flight crewto clearly identify on the ECAM, all the procedures/ status messages affected by an OEB.

When a warning / caution occurs, a messageinforms immediately the flight crew that an OEBexists for the corresponding displayed alert / status.In this case, the flight crew must refer to the QRHinstead of the ECAM procedures.

Three cases may arise:l Only the ECAM procedure is affectedl Only the status message is affectedl Both the ECAM procedure and the corresponding

status messages are affected

Only the ECAM procedure is affected: The ECAM alert title and related status messagesdo not change. All the corresponding actions aresuppressed and replaced by a REFER TO QRHPROC message.

Example:

Only the ECAM status messages are affected:The ECAM alert title and related status messagesdo not change. The corresponding procedure doesnot change, except for the additional FOR STSREFER TO QRH line. The related status messageson the ECAM do not change, except for theadditional REFER TO QRH PROC title.

Example:

Both the ECAM procedure and the corresponding status messagesare affected:The ECAM alert title does not change. All thecorresponding actions are suppressed and replacedby a REFER TO QRH PROC message. The relatedstatus messages on the ECAM do not change,except for the additional REFER TO QRH PROCtitle.

Example:

4

AIR PACK1 OVHT

-REFER TO QRH PROCECAM UPPER DISPLAY (E/WD)

STATUS

.WHEN PACK OVHT OUT: INOP SYS

-PACK1........ONPACK1 ECAM LOWER DISPLAY (SD)

AIR PACK1 OVHT

-REFER TO QRH PROCECAM UPPER DISPLAY (E/WD)

STATUS

REFER TO QRH PROC INOP SYS

.WHEN PACK OVHT OUT:PACK1

-PACK1........ON ECAM LOWER DISPLAY (SD)

AIR PACK1 OVHT-PACK1.......OFF

WHEN PACK OVHT OUT:-PACK1.......ON-FOR STS REFER TO QRH

ECAM UPPER DISPLAY (E/WD)

STATUS

REFER TO QRH PROC.WHEN PACK OVHT OUT:

PACK1-PACK1........ON

ECAM LOWER DISPLAY (SD)

Activation of the OEBReminder function:When an ECAM warning / caution is affected byan OEB, an OEB Reminder code is provided inthe operational documentation (FCOM Vol.3 &QRH). This code allows the operator to activatethe OEB Reminder function for the concernedECAM warning / caution, according to the AMMtask (Load OEB Reminder information into FWCusing MCDU).

4 Activation /deactivation of the OEBReminder function:

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# 04 June 2007

It is important to note that the aircraft operational documentation has to be updated before or atthe same time as the activation of the OEB Reminder function since the actions of the affectedECAM alert may be suppressed (the flight crew is asked to refer to the QRH).

6

Deactivation of the OEB Reminder function:Once a corrective solution is available, Airbusprovides an associated SB that allows the retrofitof the corrective modification. As soon as the SBis retrofitted, the OEB Reminder function has tobe deactivated according to the AMM task (DeleteOEB REMINDER information into FWC usingMCDU).

It is important to note that the aircraft operational documentation has to be updated at the sametime or after the deactivation of the OEB Reminder function.

6 ConclusionThe OEB reminder function provides help to theflight crew by enabling them to clearly / easilyidentify ECAM procedures overridden by OEBs. Itis a very good tool to assure that the flight creware made aware of the correct procedure when aTemporary Procedure overrides the ECAM.

Operators have to be aware that this device requiresspecial attention and a specific management shouldbe put in place. The Operational Engineering andthe Aircraft Engineering, as well as the MaintenanceControl Center, have to be involved in a commonprocess to deal with the OEB reminder function.

For long-range aircraft, the OEB reminder functionis optional, and is free-of-charge through RFC/RMOService Bulletin (SB) 31-3020 for A330 aircraft,and SB 31-4032 for A340 aircraft.

For single-aisle aircraft, Airbus has launched afleet-wide, free-of-charge, Airbus-monitored retrofitcampaign (SB 31-1264) that consists of upgradingthe FWC to the H2F2 Standard for all single-aislefamily aircraft. This retrofit campaign also includesthe optional activation of the OEB reminderfunction (for additional information, please refer tothe Retrofit Information Letter (RIL), referenceSER/916.0551/06, dated Nov. 15, 2006).

Note: This device does not exist on A300-600 /A310 Family.

5 OEB reminderfunctionAirline implementation

The OEB Reminder function was presented duringthe Operations Liaison Meeting 2006 and duringthe last 15th Performance & Operations Conferenceheld in Puerto-Vallarta,Mexico, in April 2007.

These conferences, together with a survey thatwe conducted do confirm the following:As indicated in chapter 4 above, appropriatecoordination between the Flight Operations andMaintenance / Engineering departments within theairline is key to an efficient implementation andoperation of the OEB reminder function.

Analysis of positive answers from airlines thatuse the function shows that an adequateimplementation process is as follows:Step 1: Each OEB is validated by the OperationalEngineering.Step 2: The documentation (FCOM and QRH) is updatedand distributed. Step 3: If there is an OEB reminder code to be activated,the item is handed over to theMaintenance Engineering to activate the code onthe Flight Warning Computer (FWC) of the aircraft.Step 4:During the retrofit of the correcting modification,the deletion of the OEB reminder code is integrated in the work orderStep 5: Once the retrofit is completed for all aircraft of thefleet, the documentation is updated.

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# 04 June 2007

Airbus flight operations support department remains available for any additional

information or assistance :

Email: [email protected]

8

Avoiding high speedrejected takeoffsdue to EGT limitexceedance

By: Arnaud BONNETEngine Performance Manager

1 IntroductionUnnecessary high speed rejected takeoffs areexperienced from time to time due to high ExhaustGas Temperature (EGT). The goal of this article is to explain that a too highEGT overlimit must not lead to abort a takeoff athigh speed.The first part will provide some technical backgroundon EGT and will outline the operational recom-mendations and Aircraft Maintenance Manualprocedures in case of limit exceedance.The second part will describe maintenance andoperational procedures, which minimize EGT overlimit occurrences.

2 EGT is a goodindicator of enginehealth

As engines accumulate cycles, their performancetend to deteriorate due to various reasons, e.g.:l Dust/dirt ingestion and further accumulation on

fan blades/compressor airfoils.l Increasing tip clearances on compressor / turbine

blades and seal clearances due to rub.

l Other mechanisms such as erosion of airfoilsand seals, hot section oxidation and increasedair gas path air seal wear.

The High Pressure (HP) compressor and the HPturbine are generally the main contributors todeterioration. On some higher bypass ratio engines,the low pressure (LP) compressor may also be asignificant contributor.

The appropriate indicator of the overall performanceof the engine (compressors and turbine) is basedon the core flow temperature, which is measuredat the turbine exit and is referred to either as EGTor TGT, for Turbine Gas Temperature on Rolls-Royce engines.

The above temperature is measured in the gaspath, either at the Low Pressure (LP) turbine inlet(on CFM, EA, GE and RR engines) or at the LPturbine exit (on PW and IAE engines).

3 Demonstration ofEGT operational limit

To protect turbine hardware, an operational limiton EGT (called EGT red line) is demonstratedduring endurance tests required for FAR 33/JAR-E/EASA engine certification.

During such tests, the engine is run for 25 stagesof 6 hours each. For each stage, the engine spendsup to one hour cumulative time at max takeoffregime, with average EGT at redline conditions.

Moreover, FAR 33 engine certification requires theengine to run for 5 minutes with N1 and N2 at redline levels and with EGT at least 42C above thered line. After the run, the engine is disassembledand the turbine assembly must be within serviceablelimits.

4 What is takeoff EGTmargin and how is itcalculated?

EGT Margin is an estimate of the difference betweenthe certified EGT redline and a projection of engineEGT to full-rated takeoff at reference conditions.

The observed EGT is projected to a standardreference condition of takeoff full power, on a flat-rate temperature day at sea level, usingcharacteristics derived from the EngineManufacturers thermodynamic model for the enginerating. This projected temperature level representsthe expected EGT if the takeoff actually occurredwith the reference conditions. The projected EGTlevel is then subtracted from the certified EGTredline for the particular engine rating in order toproduce an estimated takeoff EGT margin.

Therefore the EGT margin is not just the differencebetween recorded EGT at takeoff and the EGTredline, since it is very unlikely that the takeoff datawere recorded at the reference power level,temperature day, and bleed level.

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# 04 June 2007

5 Use and limitationsof EGT marginprojections

EGT margin is routinely used to monitor the healthof installed engines through the ECM tool (EngineCondition Monitoring), together with cruiseperformance trends, takeoff EGT margin trendsare used to detect shifts in performance for eachengine, which can indicate the need for inspectionsand/or maintenance. The EGT margin trends arealso used to forecast an average remaining timeon-wing, if engine removal is due to takeoff EGTmargin shortage.

However:l Calculated EGT margin should not be used as

sole criterion for engine removal. Apart from theLife Limited Parts constraints, it should beconsidered with other factors such as cruisetrends, number of EGT over limit occurrencesand the associated maintenance tasks requestedby AMM prior to an engine removal decision.

l Takeoff EGT margin has a limited accuracy, drivenby:- the accuracy of recorded flight conditions and

engine parameters,- the fact that the performance model included

in the ECM tool is representative of the averagebehaviour of production engines, but not ofevery single engine.

Further, recall that EGT margin is calculated for areference condition, typically a full-power takeoff, ona flat-rate temperature day, at sea level. This conditionis not necessarily the most severe condition; theworse condition can be different for different enginemodels. So, EGT margin is frequently not projectedfor the worst case. However, this representative

6 What is OATL?(Outside Air Temperature Limit)

For the engines whose takeoff EGT is nearly constantwith increasing Outside Air Temperature (OAT)beyond Tref (flat rate temperature), OAT Limit (OATL)is another related indicator of engine health fortakeoff. OATL is a projection of the highest ambienttemperature at which an engine should be able toproduce full flat-rated thrust without exceeding EGTredline. Thus, this parameter describes an enginestakeoff performance capability in operational termsthat can be used directly by Flight Operations. Notethat OATL and EGT margin are similar measuresof performance based on takeoff data; theseparameters are not independent assessments ofthe temperature limitations for an engine. Forinstance, when the OAT Limit equals the flat-ratedtemperature for an engine, the EGT margin is zero.

condition permits trending takeoff margin ona consistent basis. Factors such as ambienttemperature, amount of derate, time since previousoperation of the engine, altitude of the runway canimpact the actual peak-EGT during any given takeoff. Therefore:l An engine with a slightly positive takeoff EGT

margin may experience EGT over limit at takeoffl An engine with a slightly negative takeoff EGT

margin may not necessarily experience EGT overlimit at takeoff.

10

EGT red line

Take

off

EG

T

EGTM4

EGTM3

EGTM2

EGTM1

New Engine

NegativeEGT

margin

PositiveEGT

margin

OATFlat Rate Temperature

OA

TL4

OA

TL3

OA

TL2

OA

TL1

As the engine accumulate cycles, EGT margin (EGTM) and OATL decrease

OAT Limit (OATL) is a projection of the highest OAT at which an engine should be able to produce full flat-rated takeoff thrust without exceeding EGT redline. When OATL is below the Flat Rate Temperature (i.e.EGT margin is negative), EGT over limit may occur during a full rated takeoff.

Incr

easi

ng F

light

Hou

rs

Fig 1: Engine Deterioration Effect on EGT margin and OATL

8 Aircraft MaintenanceManual procedures in case of EGT over limit:

To increase the operators flexibility for engineremoval and allow the aircraft to fly back to its mainbase whenever possible, maintenance tasks havebeen defined according to the magnitude of theEGT over limit and its duration. Those tasks rangefrom a visual inspection up to a required engineremoval and overhaul. As a reminder, this latitudegiven to operators is not a means of extending on-wing life for EGT limited engines, but aims at offeringflexibility, to avoid Aircraft On Ground (AOG)situations at other stations than the main base.

The chart below shows an example of AMM chartfor the CFM56-5C:In this particular example, three areas referred toas, A, B and C, were originally defined accordingto the magnitude of EGT over limit and the durationof the event. To each area corresponds a specificmaintenance action.At a later stage, it was decided that within A,occurrences implying EGT over limit of less than10 degrees Celsius with a duration of less than 20seconds did not call for any maintenance action.This particular area is referred to as D.

7 Operationalrecommendations:

An EGT over limit due to normal engine wear doesnot affect the engine thrust, safe continuation ofthe takeoff is therefore possible.

Below 80 knots, an ECAM caution will trigger andthe takeoff may be aborted.

Above 80 knots, ECAM caution is inhibited, nocrew action required.

During flight phase 4, from 80 knots to lift-off, theFlight Crew Operating Manual (FCOM) procedurein case of EGT over limit calls for continuation ofthe takeoff. On all fly by wire aircraft, EGT over limitECAM cautions are inhibited during this flight phasewhereas the EGT indication will become red asEGT goes beyond the red line. The intent is toavoid distracting the pilot during a critical flightphase with information that might causeinappropriate crew response.

After lift-off, the ECAM procedure should be appliedwhen the appropriate flight path is established andthe aircraft is at least 400 ft above the runway.Pending the magnitude of the EGT over limit, theECAM will call for different procedures, as illustratedin the following figure.

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Allowance for CFM56-5CEGT over limitsIn order of gravity:

Area DEGT over limit of less than 10C and during less than 20 seconds are permitted, without any requestedmaintenance action

Area AInspection and troubleshootingrequired.Maximum of 20 over limitoccurences allowed beforeengine removal

Area BInspection required. If root cause not identified, borescope inspection required.20 over limit occurrencesin area A & B combined or 10 in area B allowed before engine removal

Area CRemove the engine and return to shop.One non-revenue flightallowed if no damage beyond serviceable limits.

1

890

900

910 915

920

930

940

950

960

965 970

975 980

990

2 3 4 5 6 7 8 9 10

TIME MINUTES (PHYSICAL TIME)

INDICATED EGT (T495) C

A

B

A

B

C D

CO

CK

PIT

IND

ICAT

ION

(IN

DIC

ATIO

N M

AX

)

TAKE OFF NORMAL OPERATION

MAXIMUM CONTINOUS NORMAL OPERATION

A340

The following recommendations should be appliedin priority to those engines.

Engine wash:Each engine manufacturer has issued recom-mendations on intervals between two washes.Each operator, based on their various constraints,e.g., environmental, may tailor those intervals.Average EGT margin recovery based on operatorsfeedback to engine manufacturers is around 7C(up to 15C).

Air conditioning selection:l Full rated takeoff operations:

On twin engine Airbus aircraft, the EGT level isquite similar regardless of air conditioning selection(bleed ON or OFF). Power setting decrementassociated to bleed selection is designed toachieve that result.

9 Maintenance/Operational procedures tominimize EGT overlimit occurrences:

Follow-up of engine performance with the EngineCondition Monitoring tool allows focussing attentionand efforts on engines with limited takeoff EGTmargin.

Within each operators constraints, operations onmost demanding routes of aircraft equipped withsuch EGT limited engines should be avoided.

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10 Conclusionl To minimize EGT over limit occurrences, use

engine trend monitoring and consider the followingactions for aircraft equipped with reduced EGTmargins: - Avoid operations on demanding routes- Conduct regular water wash.- On quad engine aircraft, privilege bleed ON for

full rated takeoff and bleed OFF for flex takeoffoperations.

- Consider longer warm-up time to reduce EGTpeak level at takeoff.

l Operations of engines with very low takeoffEGT margin may lead to a risk of unnecessaryhigh speed rejected takeoff. This riskincreases as ambient conditions and powersetting get closer to the worst-case conditions(full power, day temperature at or above flatrate temperature). If an EGT over limit occurs when the aircraftspeed is above 80 knots, the pilot shouldcontinue the takeoff and wait for the flightpath to be established, at an altitude of atleast 400 feet above the runway; beforeapplying the appropriate ECAM procedure.

On quad engine Airbus aircraft, the power settingdecrement is designed to reach the same EGTlevel with bleed ON as with bleed OFF, whenone engine feeds one air conditioning pack (failurecase). EGT levels at full rated takeoff are thuslower with bleed ON than with bleed OFF.

l Flex takeoff operations:At constant takeoff weight, switching OFF theengine bleed allows operation of the engines athigher flex temperatures than with bleed ON.This leads to lower EGT level.

Example: To illustrate this point, let us consider an A340-300 equipped with CFM56-5C4 engines, takingoff from an airport at 8 600 feet altitude , with a10C OAT:With air conditioning ON (on the engine) and Tflex= 17C, aircraft TOW= 225 tons.Same TOW with air conditioning OFF (or ON butfrom the APU) is achievable with Tflex = 23C,leading to EGT 10C lower than with bleed ON.

Engine warm-up time:Cold engine takeoff can lead to higher peak EGTvalues than with warm power plants. The FCOM recommends a minimum engine warm-up time to avoid engine damage. Extending the engine warm-up time beyond thisminimum recommended will lower peak EGT valuesat takeoff.

Example: The A340/CFM56-5C FCOM quotes a 2-minuteminimum engine warm-up time before takeoff.Increasing this warm-up time to: 10 minutes provides an average 9C lower peak

EGT, 15 minutes provides an average 12C lower peak

EGT.

Note: Extending the warm-up time show morebenefit on takeoff peak EGT for engineswith single stage HP turbines than forthose with two-stage HP turbines.

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14

Do you know yourATC/TCAS panel ?

By: Bernard VIGNAULTFlight Operations Safety Enhancement Engineer

1 TCAS Fault leadsto AIRPROX

Shortly after takeoff from London Heathrow, theECAM alert TCAS FAULT was triggered in an AirbusA340-600. The ECAM procedure consists in settingthe TCAS mode to standby. Unfortunately, theeffects of the action were not the expected ones:the crew inadvertently switched off both transponderand TCAS instead of selecting the TCAS stand-by mode as per ECAM procedure. The Air TrafficControl secondary radar information was temporarilylost and prevented the automatic update of theflight data. In other words, the aircraft disappearedfrom the ATC radar screen and was not able torespond to other aircraft TCAS interrogation.During this time the Tower Traffic Controller triedto contact the approach centre. Although severalattempts were made the calls were not answered.Unknown to the approach controller, the aircraftwas climbing in conflict with another departingaircraft. As the aircraft transponder was notresponding, no TCAS alerts nor Short Term ConflictAlert (in Air Traffic Control) triggered and theminimum separation reduced to 3.7 NM and 0 ft.

2 TCAS controlsLet us have a closer look to the ECAM procedureand to the TCAS controls, to understand thisscenario.

When the TCAS fails, the ECAM procedure indicates(on A340/330): TCAS MODE..STBY (Seefig 1).

Fig 1: CAS FAULT ECAM procedure on A330/340

The crew is expected to set the faulty system onstandby. In the above event, the airline had chosen for itsfleet the TCAS panel, which is shown in figure 2.

On this panel, a single rotating selector enables thecrew to switch between several modes, linked to ATCtransponder and/or TCAS. When the selector is placedin TA/RA or TA ONLY positions, both TCAS and ATC

transponder operate. But if the selector is placed inone of the three other positions (XPNDR, ALT RPTGOFF, STBY), then the TCAS is on standby mode.In their intention to set the TCAS only on standbymode, as requested by the ECAM, the crew turnedthe selector until it reached the STBY position. Theydid not immediately realize that this position set boththe TCAS and the ATC transponder on standbymode.

3 Other TCAS ControlPanels

Several types of panels are available to customers,and pilots have to pay attention to the switcheslayout when operating them, as functions maydiffer from a panel to an other.

On Airbus basic TCAS panel, the controls are splitinto two parts: l one side of the panel is dedicated to ATC

transponder controlsl the other side is dedicated to TCAS control.

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Fig 2: Gables 40 ATC/TCAS control panel

TCAS + Transponder in standby

TCAS standby / Transponder On

TCAS + Transponder ON

16

Setting the TCAS mode to standby is done bysetting the appropriate switch to the STBY position.The switch is easily identified, as it is located withother TCAS controls, and separated from ATCtransponder controls (see fig 3).When the TCAS switch is placed on the STBYposition, the TCAS is electrically supplied but isinoperative, and the ATC transponder still operatesnormally. As a result, there will be no TCAS TA orRA on board the aircraft whose TCAS has beenset to stand-by. However, the ATC transponderwill be able to continue responding to potentialintruder interrogation, and TA/RA information willcontinue to operate on-board the intruder.

Other designs exist for ATC/TCAS panel, on whichTCAS setting on standby is achieved by settingthe selector to XPNDR, STBY, ON or OFF,depending on which TCAS control panel is installed.On Gables 10 panel, for example, the selectorshould be turned from the normal TA/RA positionto the ON position to set the TCAS on standby(see Figure 4). The ON legend is related to the ATCTransponder only. This is indicated by the fact thatthe ON legend is out of the settings related to theTCAS, that are gathered by a line associated to aTCAS label.

TCAS

ATC

AUTO ON

TRAFFIC

XPDR

XPDR

SBY

ON TA RA/TATCAS

FAIL

1 2

IDNT

ON OFF

ALT RPT

Fig 4: Gables 10 ATC/TCAS control panel TCAS on standby

Fig 3: Basic ATC/TCAS control panel

17Safety First


# 04 June 2007

On Gables 20 panel, ATC transponder and TCAShave dedicated controls. TCAS is set on standbyby placing the TCAS selector to the OFF position(see Figure 5).

4 New ECAM procedureSetting the TCAS to standby mode can beachieved by setting the selector to XPNDR,STBY, ON or OFF, depending on which TCAScontrol panel is installed.

The Flight Warning Computer that generates theECAM procedure in case of a TCAS fault has nomeans of determining what type of ATC/TCAScontrol panel is installed. It is therefore not possibleto provide the crew with a customized ECAMprocedure indicating the setting to be reached foreach panel.

This is why the TCAS FAULT ECAM procedure isgeneric and provides the objective of the actionto be performed: TCAS MODESTBY. It is thenup to the crew to place the right selector in theright position.

ECAM ChangeSetting the TCAS on stand-by when it is faultyenables to remove the TCAS FAULT flags on PFDand ND.

But the related in-service event highlighted thedifficulty for the crew to use the right setting whenthe word STBY is displayed on the ECAM witha panel that differs from the AIRBUS standard one.Airbus then decided to remove the action line TCASMODE..STBY from the ECAM procedure andto accept the drawback of the flags remaining onPFD and ND after the failure. This modification willbe effective upon fitting with new FWC standards.This modification is only applicable to Long Rangeaircraft, as the TCAS FAULT procedure is crewawareness only (no action line) on Single Aisle andA380 aircraft, and there is no ECAM warning forTCAS failure on A300/A310 family.

In the interim period before FWC standards areinstalled, AIRBUS published an OEB to informcrews not to apply the action line TCASMODE..STBY, in the case of a TCAS FAULTECAM caution. The TCAS FAULT ECAM cautionshould be considered as a crew awareness.

This information was dispatched to airlines throughFOT 999.0138/06 on 11th December 2006. Thecrews are informed of the deviation from ECAMprocedure by:l OEB 68/1 for A330 aircraft (cancelled by FWC

STD 2)l OEB 82/1 for A340 aircraft (cancelled by FWC

STD L11 for A340-200/300 aircraft and FWCSTD T2 for A340-500/600 aircraft)

TCAS

ATC

OFF

ONAUTO

STBY

TATARA

1

1

2

2

3

4 5 6

7 0 CLR

ATC1

IDNT

XPDR

FAULT

Fig 5: Gables 20 ATC/TCAS control panel TCAS on standby

18

Managinghailstorms

By: Albert URDIROZFlight Safety Manager

1 IntroductionIn the second issue of this magazine, datedSeptember 2005, readers found information onturbulence encounter and avoidance in an articletitled Managing severe turbulence. Further tothis, we will here discuss about the possibleconsequences of hailstorm encounter and theadequate prevention means.

No civil air transport aircraft structure is designedto absorb large hailstone impacts without damage.In conditions of extreme hailstorm encounter,consequences like destruction of the radome, lossof visibility through the two front windshields,unreliable air data or engine failure may turn outto jeopardize the safety of the flight.

Safe operations therefore consist in avoiding areasof hailstorms by relying, like the avoidance ofturbulences, on the efficient use of weather radar.The effectiveness of the latter has been increasedby the introduction of enhanced weather radars.

In order to illustrate this discussion, we will referto in-service events that have been experiencedby a few Airbus operators. Events with similarstructural and operational consequences havebeen reported to occur with other aircraft type.

2 Possible damages to the structureand engines

Windshields Most of the civil air transport aircraft share thesame design of windshields, made of two innerplies that ensure the structural strength, and ofone outer ply. The structural plies will withstandimpacts, but the outer ply may be damaged. Evenif strength is not compromised, effects may besignificant in terms of visibility, as shown by thispicture taken after flight into a severe hailstorm.

RadomeIn most of the severe hailstorm encounters,radomes suffer body damages but still fulfill theirfunctions of fairing and protection for the radarand antenna. However, the air transport industryhas recorded a few occurrences of radomes beingdestroyed.

Fuselage, wings, antenna, probes etcLeading edges and protruding components maybe damaged, or may brake when overstressed.

EnginesEven if Airbus has never received such report, theair transport industry has recorded someoccurrences of engine(s) flame-out due to ingestionof hail.

3 Possible subsequentconsequences

All the communication and navigation aid systemsmay become inoperative when antennas aredamaged (VHF, VOR, ADF etc..)

In addition, destruction of the radome may imply:l Further structural damages upon impact with

radome debrisl In isolated cases, engine flame-out upon ingestion

of these debrisl Loss of the radar and attached wind shear

prediction functionl Loss of ILS informationl Unreliable Air Data situation from disturbed airflow

along the probes located downstream of theradome (Ref. sketch, probes location on A320family).

Unreliable Air Data situation may also result fromhail impacting the probes.

A fly-by-wire aircraft experienced such a situationrecently. Because pitot probes were impacted byhail, airspeed information was affected. Systems responded as follows:l F/CTL NAV ADR DISAGREE was triggered;l Electrical Flight Controls Systems reverted to

alternate law;l Autopilot and auto thrust disengaged;l Flight directors were no longer available.

All these effects resulted from the unreliable airspeedflight conditions, which the crew had to manageas per ECAM.

During the same event, the windshield outer plywas damaged, as shown on the picture above.Autopilot, autothrust and flight directors were notrecovered when the aircraft flew out of the hailstorm.

An emergency landing was performed, in thefollowing adverse conditions:l no autoland capability,l no ILS guidance,l no visibility through the front windshield.The crew was able to land with the sole visualreferences obtained through the lateral cockpitwindows.

19Safety First


# 04 June 2007

CAPT AOA PROBE

STBY STATIC PORT

CAPT TAT PROBE

CAPT PITOT PROBE

STBY PITOT PROBE

CAPT STATIC PORT

CAPT STATIC PORT

F/O STATIC PORT

F/O STATIC PORT F/O TAT PROBE

F/O PITOT PROBE

STBY STATIC PORT

F/O AOA PROBESTBY AOA PROBE

Probes location

4 Prevention means

The Flight Operation Briefing Note entitled "Optimumuse of weather radar" explains how to tune weatherradar in flight and to interpret the informationdisplayed. It then considers the decisions to takein terms of adverse weather avoidance.

This document highlights that adverse weathermanagement relies on:l Awareness of weather radar capabilities and

limitations;l Active and optimum use of radar, with crew tuning

the range, gain and tilt;l Flight crews interpretation of the Navigation

Display radar image;l Relevancy of decisions taken.

One of the radar limitations is that it indicatespresence of liquid water. It does not identify thenature of returns, i.e. displays will not positivelyindicate presence of hail.

Consequently, avoiding hailstorm areas not onlyrelies on the adequate use of the weather radar,but also on the good understanding of the structureof the cumulonimbus clouds that producehailstorms.

Airbus recommends that this briefing note be usedfor training purposes and be made available tocrews for developing and maintaining their radarusage knowledge.

20

Reflectivity

Ground Clutter

Wet Hail

Rain

Wet Snow

Dry Hail

Dry Snow

Drizzle

Fig 4: Reflectivity Acording to Droplet Type

Fig4: The Risk of Encountering Hail relative

to Cb Cloud Position

5 Adverse weatherradar avoidanceinitiatives

Airbus and the weather radar manufacturerscontinuously cooperate in increasing radarperformance and have introduced enhancedweather radars, which:

l Are more sensitive and accurate;l Use pulse compression technology and

algorithms;l Scan airspace ahead of the aircraft out to 320NM

and up to 60,000 feet; l Feature 3D display of aircraft route (Ref. picture);l Feature Auto-tilt.

These enhanced weather radars are proposed atentry into service for new programmes (A380,A350). Feasibility of introduction onto otherprogrammes is under study.

6 ConclusionIn extreme situations, hail encounter may result in:l Severe damages to the structure,l Engine flame-out,l Major systems disruptions,and thus may jeopardize the safety of the flight.

Consequently all efforts should be made to avoidhailstorms areas. In that perspective, crews shouldoptimally use the weather radar, i.e. adapt thetuning to the flight conditions and correctly interpretthe information displayed, in order to take theappropriate decisions. Useful information is providedin the dedicated Flight Operation Briefing Notetitled "Optimum use of weather radar".

Enhanced weather radars features, nowimplemented on new programmes, may beconsidered for introduction on in-service aircraftas available. For more information contact yourCustomer Support Manager or your dedicatedUpgrade Services Manager.

21Safety First


# 04 June 2007

The briefing note dedicated to the optimumuse of the weather radar can be downloaded

from the Airbus Safety Library website:

http://www.airbus.com/en/corporate/ethics/safety_lib/

22

Introducingthe MaintenanceBriefing Notes

Uwe EGGERLINGDeputy Vice President,Maintenance EngineeringServices, Customer Services

2 Introducing the MaintenanceBriefing Notes

Statistics on the contribution of maintenance errorsto incidents and accidents vary widely, from 5 %as a primary cause up to 30 % as a contributingfactor. Maintenance errors also impact theprofitability of operations, being responsible for 15% of delays, 50 % of delays / cancellations dueto an engine-related cause and 20 % of in-flightshutdowns.

1 Airbus BriefingNotes ConceptGoes Global

Briefing Notes have been developed to constitutea safety-awareness reference for all aviation actors,regardless of their role, type of equipment andoperation.

Briefing Notes provide an equal focus on FlightOperations, Cabin Operations and Maintenance.

The Issue # 01 - January 2005 - of the Safety Firstmagazine introduced the Flight Operations BriefingNotes - A Tool for Flight Operations SafetyEnhancement (see feature article on pages 23-25).

The Issue # 03 - December 2006 introducedthe Cabin Operations Briefing Notes A Tool forCabin Operations Safety Enhancement (see featurearticle on pages 27-29).

With this Issue # 04, Airbus is pleased to introducethe Maintenance Briefing Notes series.

Acknowledging that human errors can be reducedbut not eliminated, error-management offers oneof the promising avenue for safety enhancement.

The Maintenance Briefing Notes series was createdto provide an eye-opening and self-correctingapproach to human performance in maintenance.This publication will provide operators with lessons-learned derived from real-life case studies,highlighting :l Statistics;l Applicable procedures and best practices;l Involved technical and human factors;l Company prevention strategies / personal lines-

of-defenses; and,l Reference Airbus or regulatory material.

Maintenance Briefing Notes are developed by apanel of experts in engineering, human factors,scheduled and unscheduled maintenance,maintenance documentation and maintenancetraining.

3 Scope ofMaintenance Briefing Notes

The first Maintenance Briefing Note, issued inDecember 2006, is dedicated to HumanPerformance and Limitations, highlighting thechallenges resulting from the traffic growth andincreased demands upon aircraft utilization, thepressure of maintenance operations for on-timeperformance and the resulting growing need foran enhanced awareness of the importance ofhuman factors issues in aircraft maintenance.

The upcoming Maintenance Briefing Notes willfurther explore subjects such as :l Craftsmanship;l Standard / best industry practices;l Specific techniques; and,l Trouble-shooting.

4 ConclusionFlight safety enhancement has often focused onoperational issues. The Airbus Maintenance BriefingNotes are intended to tackle maintenance issues,thereby contributing to the enhancement ofmaintenance.

23Safety First


# 04 June 2007

The Flight Operations Briefing Notes, theCabin Operations Briefing Notes and theMaintenance Briefing Notes constitute

respectively the Volumes 1, 2 and 3 of theAirbus web Safety Library posted on the

Airbus corporate website

http://www.airbus.com/en/corporate/ethics/safety_lib/

24

A320 - Dualhydraulic loss

By: Michel PALOMEQUEFlight Safety AdvisorA318/A319/A320/A321 program

1 IntroductionThe A320 may experience a series of dual hydraulicloss when, at low altitude, a leak in the greenhydraulic system causes the loss of the yellowcircuit. To understand how this may happen, this articlewill first describe the aircrafts hydraulic systemand explain the respective roles of the PowerTransfer Unit (PTU) and ECAM caution in case ofpressure differential between the green and yellowsystems. The second part of the article will describe howthe combination of a major leak in the green circuitand the ECAM inhibition below 1,500 feet maylead to the dual hydraulic loss. The third and last part will develop on the correctiveactions proposed to avoid this type of occurrences.

2 General overviewThe A320 hydraulic system is composed of threedifferent and fully independent circuits: Green,Yellow & Blue. The users are shared between thesystems in order to ensure the control of the aircraft,even when one system is inoperative.

On the blue hydraulic system, the normal sourceof pressure is the electrical pump, and the auxiliarysource is the Ram Air Turbine (RAT). The Constant

Speed Motor/ Generator (CSM/G) is used to provideaircraft electrical power in case of emergency.

On the green & yellow systems, the normal sourceof pressure is the Engine Driven Pump (EDP) andthe auxiliary source is the Power Transfer Unit(PTU). The PTU is a hydraulic motor pump whichtransfers hydraulic power between the green andyellow systems without transfer of fluid.It operates automatically, whenever the pressuredifferential between the two systems reaches500 PSI.

In case of low fluid level in either the green or yellowsystem, an amber caution is triggered on the ECAM,which requests the pilot to switch off the PTU aswell as the EDP. This to avoid having the PTUrunning at maximum speed and causing theoverheating and loss of the properly functioninghydraulic system.

According to the Airbus philosophy of notoverloading the flight crew during the critical phasesof flight, the above amber caution is inhibited below1,500 feet.

The figure below shows all the systems, which areinterconnected to the hydraulic systems:

25Safety First


# 04 June 2007

M M

FLIGHT CONTROLSLANDING GEAR

BRAKESNOSE WHEEL STEER

REVERSER ENG 1

3000 PSI 3000 PSI 3000 PSI

ACCUMULATOR ACCUMULATOR ACCUMULATOR

ENGINE DRIVEN PUMP (EDP)1

ENGINE DRIVEN PUMP (EDP) 2

ENG 1 FIRE

SHUT-OFF VALVE

ENG 2 FIRE

SHUT-OFF VALVE

GREENRESERVOIR

BLUERESERVOIR

RAM AIR TURBINE

(RAT) ELECTRIC

PUMP ELECTRIC

PUMP

POWER TRANSFER UNIT (PTU)

FLIGHT CONTROLSCONSTANT SPEED

MOTOR/GENERATOR

FLIGHT CONTROLSBRAKES

PARKING BRAKEREVERSER ENG 2

CARGO DOOR

YELLOWRESERVOIR

HAND PUMP

SS

PTU is automaticallyoperated when a certain

P (500PSI) appearsbetween Green

and Yellow circuits.

SYSTEM OVERVIEW / RATExample of architecture.

Aircraft pre modification 26925.

26

3 Dual hydraulic lossscenario

The scenario of the dual hydraulicloss is the following:

1) During takeoff, a leak in thegear retraction circuit leads tothe loss of the green hydraulicsystem. This loss stops theretraction of the landing gear.

2) The 500 PSI pressure differen-tial between the green andyellow hydraulic pressure isreached and the PTU auto-matically switches ON.

3) The loss of the green systemnormally triggers the corres-ponding ECAM caution, whichrequests the crew to switch offthe PTU.

4) However, below 1,500 feet, theECAM caution is inhibited.

5) The PTU therefore remainsON, and operates at its maxi-mum speed.

6) As a consequence of the nonretraction of the landing gear,the crew may be busy commu-nicating with ATC and mana-ging the situation, leaving theaircraft flying below 1,500 feetlonger than usual, and thuskeeping the ECAM cautioninhibited.

7) Within less than two minutes,the PTU overheats the yellowhydraulic system and causesits loss.

G RSVR LOLVL (inhibitedbelow 1500ft)

Y RSVROVHT

(inhibited below1500ft)

G+Y SYS LO PR(displayed above 1500ft)

1500ft

PTU &pumps areswitched

OFFPTU notswitched

OFF

PTUduration

Automoaticstars

of the PTU

Sudden increase ofthe hydraulic leak

Lift off

Green hydraulicleakage

Landing gear retractiontentative

In case of green low level, if PTU is not switched off this will lead to A Yellow overheat (around 2 minutes later) Then to a double G+Y hydraulic failure

As a summary, the following figurecan be used to describeshortly the scenario ofthe dual hydraulic loss:

4 Corrective actionsThis scenario already occurred in-service, leadingto the following design change:Below 1,500 feet the PTU is automatically switchedto OFF.

This solution was preferred to the followingalternatives:l Upgrading the ECAM caution to a red warning.l Cancelling the inhibition of the ECAM warning

below 1,500 feet.

Indeed, red warnings require immediate action,which is not justified in this case, and cancellingthe inhibition would only overload the crew duringa busy flight phase.

The operational consequences of such changeare described below:

5 ConclusionThe scenario of dual hydraulic loss occurred in-service.l The green hydraulic system was lost during gear

retraction.l The PTU automatically switched ON.l The ECAM warning requesting to switch OFF

the PTU remained inhibited below 1,500 feet.l The aircraft remained below that altitude for more

than two minutes after the start of the operationof the PTU, which led the yellow system tooverheat and caused its loss.

A design change has been developed, whichconsists in the automatic switching of the PTU toOFF below 1,500 feet.


# 04 June 2007

27

In case of hyd leak in flight: No longer risk of dual hydraulic loss if no rapid

crew action. Follow G(Y) SYS LO PR ECAM caution when

triggered.Note: the ECAM procedure requests a manualconfirmation to switch off the PTU.

In case of hyd leak on ground: No PTU logic change:

Follow G(Y) SYS LO PR ECAM caution

In case of single engine taxi,or hydraulic pump failure or engine failure: No change : PTU runs to recover the normal

pressure in the affected system.

No ECAM change with new PTUlogic: ECAM still requests to switch OFF the PTU

Only Pilot confirmation (in flight) with new logic

Common ECAM definition with old logic

This change is covered by the following modifications.

MOD 34236 + 35879 / SB 29-1115: Install provisions for new PTU inhibition logic

MOD 35938 / SB 29-1126:Activate new PTU inhibition logic

Modifications 34236 & 35879are now standard on production lines

from MSN2740.

Modification 35938 is optional, and must be requested.

We therefore encourage airlines to retrofit these modifications.

28

Terrain Awarenessand WarningSystems operationsbased on GPS data

Dimitri CARSTENSENSurveillance SystemsEngineer

2 Basic principles of the new TAWS + GPS architecture :

The new TAWS architecture is based on the useof a GPS sensor (Multi Mode Receiver or GPSStand-alone Unit) linked to the TAWS computer.

Indeed, with this GPS based architecture, TAWSperformance is improved due to the better accuracyof GPS information compared to FM and ADIRUdata. The segregation of the surveillance aircraftpositioning data channel from the navigation channelensures a full independence between these twomajor avionics functions.

The GPS is linked either directly (Autonomousconfiguration - ) or through the ADIRU 1 (Hybridconfiguration most common on Airbus aircraft).In the latter configuration The ADIRU 1 is notinteracting on the GPS data delivered to the TAWScomputer, it is only used as a pass-through media.

1 Introduction

The following article is giving comprehensiveinformation on the Airbus policy promoting the useof GPS data for TAWS operations. This subjectwas introduced for the first time in Safety First #1(January 2005) through the article titled Go-Arounds at Addis Ababa due to VOR ReceptionProblems.

The two TAWS systems proposed by Airbus,EGPWS and T2CAS, were originally coupled to theFlight Management computer to gather aircraftposition and navigation data. The FM system isusing data originating from multiple sources (GPS,IR from ADIRU, Navaids such as VOR, DME, )to compute the aircraft position.

Experience has shown that FM and ADIRU datacould be affected by improper IR alignments,erroneous Navaids or improper ADR barometricsettings. These could lead to TAWS spurious alertsand unnecessary go-around procedures duringapproach and landing phases.

Consequently, Airbus developed new TAWSarchitectures where the TAWS computer takes theaircraft position data directly from the GPS sensor.

The TAWS computer uses the GPS data forpositioning the aircraft in the three dimensions:

l The latitude and longitude data are used toposition the aircraft relative to the TAWS TerrainDatabase (EGPWS and T2CAS).This can be easily implemented on the aircraftby activating the corresponding functions on theTAWS computers by simple pin programming.These functions are named Use of GPS forLateral positioning on EGPWS, and AlternateLateral Position based on GPS for T2CAS.

l The altitude data is used to compute a GeometricAltitude (EGPWS) also called Alternate Verticalposition based on GPS (T2CAS), which is a blendof the Barometric altitude, Radio Altitude, terrainand runway elevation data to ensure optimalperformance of the Basic and Terrain functionsof the TAWS computer.

As above, these functions can be easily activatedon aircraft by a simple pin programming of theTAWS computer.

In addition, when GPS data are used for latitudeand longitude, the TAWS computer is modified bypin programming to perform an automaticmanagement of the Terrain functions. Thismanagement is based on the availability andprecision of the different position sources (by orderof priority: GPS, IR from ADIRU, FM Computer).

When these position sources are neitheravailable, nor precise enough, the TAWS computerautomatically deactivates its Terrain functions.Previous deactivation had to be performed manuallywith the possible consequence, in case of omission,of potential spurious Terrain warnings during theapproach and landing phases.

Note: In case of the Terrain function deactivation,basic TAWS Reactive Modes 1 to 5remain fully operative.

29Safety First


# 04 June 2007

Hybrid architectureMost commonly used on Airbus (ADIRU 4MCU)

Autonomous ArchitecturePreviously used on Airbus (ADIRU 10MCU)

30

This new EGPWS will enable a fleet wide PartNumber commonality whatever the aircraftconfiguration, resulting in a noticeable operationalbenefit.

Airbus has developed a set of Standard ServiceBulletins for installing EGPWS P/N 965-1676-002and activating the GPS data based functions.These Standard Service Bulletins are coveringevery Airbus aircraft and have been sent to everyoperator having aircraft already equipped withEGPWS P/N 965-0976-003-206-206 or P/N 965-1676-001.In production, the TAWS + GPS architecture onEGPWS equipped aircraft has been standardizedsince January 2006.

Please refer to OIT ref. SE 999.0050/06/VHR dated18 April 2006.Please refer to SIL 34-080 rev.06 (March 2007)

3 Implementationfor the EGPWSComputer(Honeywell) :

Airbus has certified the new Honeywell EGPWSP/N 965-1676-002 for the direct use of GPS data,either in Hybrid or Autonomous configuration. The EGPWS P/N 965-1676-002 can be installedin place of previous EGPWS versions, on all Airbusaircraft.

In addition to the use of GPS data for latitude/longitude positioning and activation of the geometricaltitude, P/N 965-1676-002 also provides theavailability of Peaks and Obstacles functions forall Airbus aircraft equipped whether with EIS1 (CRT)or EIS2 (LCD) display systems.

The Obstacles function enables the EGPWS toalert the crew of possible collision with man-madeobstacles. The Peaks function enables the displayof the terrain with the elevation being relative tothe Mean Sea Level (MSL).The green number in the lower right corner of thedisplay features the lowest terrain altitude. The rednumber, just above, indicates the altitude of thehighest obstacle.

Peaks & Obs display

Please refer to OIT ref. SE 999.0050/06/VHRdated 18 April 2006.Please refer to SIL 34-080 rev.06 (March 2007).

4 Implementation for the T2CASComputer (ACSS)

The Alternate Lateral Position based on GPSand Alternate Vertical position based on GPSfunctions can be easily activated through pinprogramming on T2CAS Standard 1 P/N 900000-10110 and future Standard 2 P/N 900000-11111(certification obtained in April 07), on every Airbusaircraft.

Airbus has developed a set of Standard ServiceBulletins for the activation of these GPS data basedfunctions. These Standard Service Bulletins arecovering all Airbus aircraft families and have beensent to all operators using aircraft already equippedwith T2CAS Standard 1 P/N 900000-10110.In production, the TAWS + GPS architecture onT2CAS equipped aircraft has been standardizedsince May 2005.

Please refer to OIT ref. SE 999.0034/07/VHR Dated13 March 2007.Please refer to SIL 34-080 rev.06 (March 2007).

5 Regular update ofthe TAWS database

TAWS operations are based on the use of a terraindatabase. This database must be kept updatedregularly to the latest version to obtain the fulloperational and safety benefits of TAWS operations.

Please refer to SIL 34-080 for more informationon the terrain Database and its associateddownloading procedure.

6 ConclusionErrors in the aircraft position provided by the FlightManagement computer to the TAWS system maylead to spurious alerts and unnecessary go-arounds.

Airbus has therefore developed a new systemarchitecture, which links the TAWS computer directlyto the GPS. This solution is easy to retrofit andimproves the performance of the system.

Please refer to SIL 34-080 rev. 06 (March 2007)to find the applicable Standard Service Bulletinsfor your aircraft fleet.

For more information about FM map shifts scenariosand root causes analysis, please refer to SIL 22-043.

The Airbus Policy promoting this new TAWS systemarchitecture based on GPS data is given in OIT/FOTref. SEE999.0015/04/VHR dated 05 Feb 2004.

31Safety First


# 04 June 2007

Please refer to OIT ref. SE 999.0034/07/VHRDated 13 March 2007.Please refer to SIL 34-080 rev.06 (March 2007).

Please refer to SIL 34-080 for more informationon the terrain Database and its associateddownloading procedure.

Please refer to SIL 34-080 rev. 06 (March 2007)to find the applicable Standard Service Bulletinsfor your aircraft fleet.

For more information about FM map shiftsscenarios and root causes analysis, please referto SIL 22-043.

The Airbus Policy promoting this new TAWSsystem architecture based on GPS data is givenin OIT/FOT ref. SEE999.0015/04/VHR dated 05Feb 2004.

Yannick MALINGEVice-President Flight SafetyPhone + 33 (0)5 61 93 43 60Fax + 33 (0)5 61 93 44 29E-mail [email protected] +33 (0)6 29 80 86 52

The Airbus Flight Safety Team

Thierry THOREAUDeputy Vice President Flight SafetyHead of International CooperationPhone + 33 (0)5 61 93 49 54Fax + 33 (0)5 61 93 44 29E-mail [email protected] +33 (0)6 16 93 87 24

Christopher COURTENAYDirector of Flight SafetyHead of Safety InformationDisseminationPhone + 33 (0)5 62 11 02 84Fax + 33 (0)5 61 93 44 29E-mail [email protected] +33 (0)6 16 03 64 22

Nuria SOLERAssistant to Flight Safety Dept.Phone + 33 (0)5 61 93 45 19Fax + 33 (0)5 61 93 44 29E-mail [email protected]

Armand JACOBTest PilotOperational Advisor to the Vice-President Flight SafetyPhone + 33 (0)5 61 93 47 92Fax + 33 (0)5 61 93 29 34E-mail [email protected] +33(0)6 22 10 36 09

Jean DANEYDirector of Flight SafetyHead of In-Service Safety & Incident InvestigationPhone + 33 (0)5 61 93 35 71Fax + 33 (0)5 61 93 44 29E-mail [email protected] +33 (0)6 23 98 01 16

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32

Fligth Safety Advisors to Chief Engineers

Airbus Overseas safety Representatives

Ania BELLAGHCrisis Logistic Support ManagerPhone + 33 (0)5 62 11 86 64 Fax + 33 (0)5 67 19 12 26 E-mail [email protected] +33(0)6 12 65 06 28

Jacques KUHLFlight Safety AdvisorTo Wide Body Chief EngineerPhone + 33 (0)5 62 11 03 90Fax + 33 (0)5 61 93 48 28E-mail [email protected] +33(0)6 20 61 35 21

Andr POUTRELSafety Operations DirectorFor ChinaPhone + 86 10 80 48 61 61 (5072)Fax + 86 10 80 48 61 62E-mail [email protected] + 86 13 70 13 15 413

Armand GASTELLUCrisis Logistic Support ManagerPhone + 33 (0)5 61 93 41 79 Fax + 33 (0)5 67 19 12 26 E-mail [email protected] +33(0)6 23 98 00 86

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William G. BOZINVice-President Safetyand Technical AffairsAirbus North AmericaPhone + 1 202 331 2239Fax + 1 202 467 5492E-mail [email protected] +1 703 474 0892

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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Post/Zip Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Country . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Telephone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Cell phone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Fax. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

E-mail. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Please send me the digital copy*

Please send me the paper copy*

* Please tick the appropriate case

34Safety First


# 04 June 2007

the airbus safety magazine - becabeca.be/magazines/safetyfirst/safetyfirst-04.pdf · any airbus...

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