erroneous flaps selection at rwy holding point€¦ · linkedin.com: augusto claudio derghi cge...

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ErroneousFlapsselectionatRWYholdingpoint




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VoluntaryAirSafetyReportFlightXXYYYY:FCO–TLV

EOBT–ETA:11.20–14.40UTCTriptime:3h01m

TOW:80.500kg–Pax163Stand:610

FridayafternoonCrewarrivedonboard,fedandrested,intransitfrompreviouslegbutwithduetimebeforecurrentflight,at10.50UTC(UniversalTimeCoordinated)duetoqueueatSecuritycontrol.Duringpre-flightcheckscrewgotaCTOT(CalculatedTakeOffTime)of16.36UTC.Askingon131.9(CompanyTrafficFlowmanagementfrequency),crewacknowledgedthataNOTAM(NOticeToAirMen)wasissuedconcerningBenGurionclosureat15.00UTCwithouthavinggiventhemnoreasonaboutthatclosure(NOTAMnotincludedinthebriefingpackage).Contactedsoonafterby131.750(CompanyOperationsmanagementfrequency),crewwasinstructedtoboardpassengersaspernormalprocedure,whileOCC(CompanyOperationalControlCentre)investigatingaboutanyimprovement.Boardingstartedaround11.05UTC.At11.30UTC,TelAvivCompanySupervisor,fromBenGurionTowertomonitorthesituation,incontactwitheither131.750andEurocontrolinBruxelles,informedcrewthatiftheyhadblockedoffinfewminuteshewouldhavemanagedfortheirarrivalatdestination.Flightblockedoffat11.35UTCsoonaftersolvingthechangeofCTOTfrom16.36UTCto11.52UTCon121.725(FCORampfrequency).

Figure1:AirportGroundChart

BeforetaxingFlaps1+FwereselectedasperTODC(Take-OffDataCard)RWY25R01(Fulllength)andaircraftwasinstructedby122.125(FCOGroundWest)toproceedviaR-BholdingshortN(Figure1),forgroundfrequencychange(2engineTaxidueweight).DuringtaxiPM(PilotMonitoring)suggestedtogetTODCRWY25T01(BCintersection)readyforuse.BothcrewsagreedontheissueandPMprintedoutnewTODCforT01.OnmaintaxiwayB,crewrealizedforabout5traffictaxingaheadofthemonN,anddecidedtoslowdownabeamBCintersectiondespiteinstructed,by121.9(FCOGroundEastfrequency),toproceedfulllengthandmonitorTowerfrequency118.7.BeforeTake-Offchecklistdowntothelinewascompleted.Timeisnowaround11.50UTC.CrewthendecidedtoinformtheTowercontrollerabouttheirCTOTtoaskforanyhelp.Towercontrollerisnotkeenoncrewrequest:sequenceistoberespecteddespiteCTOT,moreoverbecauseILSRWY16Lhasbecomeunserviceablesincefewminutes,thereforeallinboundtrafficisdivertedforlandingonRWY16R.Oncetheaircraftstartedmovingagain,thenewon-dutyTowercontrollerinstructedthecrewtoproceedviaBCIntersectionandgetreadyfordeparture.PM,atthisstage,insertednewTODinFMCGMCDUPerformancepagebut,newFlapssetting(BCIntersectionrequiresFlaps2)wasnotselected.FlightXXYYYYisclearedtoenter,lineupandTake-OfffromRWY25BCIntersection.BeforeTake-Offchecklistbelowthelineisaccomplished.FewsecondsbeforeenteringtherunwayPF(PilotFlying)realizesthatFlapssettingdoesnotagreewiththeonecalculated.PMselectsnewFlapssettingandflighttookoff,continuedandlandeduneventfulatdestination.




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OccurrenceanalysisOuroccurrencecanberepresentedusingthefollowingdiagram:

Figure2:Occurrenceanalysis

WithreferencetoFigure2,2initiatingeventshavebeenidentified:1. “Take-offfromRWYintersection”;2. “CTOT,Aerodromeabouttoclose,Paxdiscomfort”;whichleadtothe“ErroneousFlapsselectionatRWYholdingpoint”event.Hence,3plausibleconsequencesoriginate:1. “Lossofcontrolsinflight”;2. “Runwayexcursion”;3. “Tailstrike”;neutralizedbyPFinterventionwho,duringline-up,spotsFlapssettingrequired/Flapsleverpositionmismatch.OperatorbarriersOnfirstcausallimb2barriersareinplace:1. “Performancecalculation”;2. “BeforeTake-Offchecklist”;Onsecondcausallimb1barrierisinplace:1. “BeforeTake-Offchecklist”;RegulatoryframeworkandCompanydocumentationforbarriersconstructionanddevelopment,herearenotconsideredandaretakenforgranted.




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WewillperformtheanalysisofthisoccurrenceusingIncidentXPtoolbyCGERiskManagementSolutions.IncidentXPcombinesthemostinnovativeincidentanalysismethodsinonesafetytool,allowingyoutochoosewhichoneyouneed.Sixmethodstochoosefromaremostinnovativebarrierbasedincidentanalysismethods,selectedforIncidentXP.Theyare:Timeline,BSCAT™,TripodBeta(TB),BarrierFailureAnalysis(BFA),RootCauseAnalysis(RCA),TOP-SET®RCA.

IncidentXPcanbeusedeitherasastand-alonemoduleorinstrictrelationwithBowTieXPvisualriskassessment.Inthissecondcase,IncidentXPmakessurelessonslearntfromincidentsaremaximizedwhentransferredtotheglobalriskassessmentasafollow-upcontribution,enhancingsafetyassuranceprocess.




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BFAmethod(BarrierFailureAnalysis)toin-deepbarriersstatusunderstandingshallbeused(Figure3)forouroccurrenceanalysis.Thismethod(3blocksmethod),consistsintheresearchofunderlyingcauseslinkedtothethreefollowingquestions:WHAThappened,WHYdidithappen,HOWdidithappen(lastonecause,tobelookedfor,athigherorganizationallevel).Followingthisapproach,theconditionof“Failed”for“Performancecalculation”and“BeforeTake-Offchecklist”barrierscanbeworkedout.

Figure3:BarrierFailureAnalysis(BFA)methodfor“Performancecalculation”and“BeforeTake-Offchecklist”barriers




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VisualRiskAssessmentLet’snowlookattheoccurrencewithinawiderandall-embracingriskanalysiscontext,whichapproachestheHazard“AircraftatTake-Off–AllWeatherOperations”leadingtoanassociatedTopEvent“Incorrectlyconfigured/unprotectedaircraftatholdingpoint”(Figure4).

Figure4:Bow-Tievisualriskassessment,AircraftatTake-Off–AllWeatherOperations

“Runwaystatus”,“Environmentalpressure(Commercial,ATC,…)”threatsand“Lossofcontrolsinflight”,“Runwayexcursion”,“Tailstrike”consequencesaretheonlylimbsenlargedforthepurposeofpresentanalysis.LeftofTopEvent,thelasttwoofseventhreats,“Runwaystatus”and“Environmentalpressure(Commercial,ATC,...)”areexactlyparentsofouroccurrenceinitiatingevents.RightofTopEvent,thelastthreeofsixconsequencesareexactlyourproposedoutcomes.Moreover,RS-01barrierisstrictlyinfluencedbytwoescalatingfactors,thefirstofthose,“RunwayIntersectionchange”(occurredtoflightcrew),piercedthroughafailedmitigatingbarrier“RIC-01Performancecalculation”.Itisworthnotingthatnomitigatingbarriersareinplaceonthelasttwoconsequentiallimbs“Runwayexcursion”,“Tailstrike”.




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EnlargingbarriersRS-01,RS-02,RIC-01,WC-01,EP-01eLOC-I-01thefollowingcanbeinferred(Figure5):

Figure5:Barrierdescription

Responsibility: AllbarriersreporttoFlightOperations;Accountability: FlightCrewaretheonlydirectactorsinterfacingwithallbarriers;Implementation:RS-02andEP-01havenewsoftwareFWC-H2F9D(seenextpage)atimplementingstage,

butonlyonsomefleetaircraft(thisisthereasonofPartiallyImplementedbarrierindicated);Nature: RS-01,RIC-01,WC-01andLOC-I-01areIncorporealbarriers:RS-02,EP-01onlySymbolic.




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Finalsummary1. OncausalandconsequentialriskassessmentlimbsnoriskdistributionisinplaceasforResponsibilityand

Accountability.FlightCrewaretheonlydirectactorsofthegameandnoalternativechoicecanbeconsideredforobviousreasons.

2. FWC-H2F9D1softwareimplementationcertainlymitigatesthefrequencyofsimilaroccurrences,sinceit

introducesapartiallyFunctionalinterface,howeveritcannotpreventoccurrencesbelongingtothefollowingscenario:FlightCrewomitseithertheinsertionofnewFMGC-MCDUFlapssettingandtheselectionofcorrespondingFlapslever,inresponseofatriggerednewdepartureconfigurationchange.

3. HumanFactorwise,aneffectiveandinexpensivecountermeasure(withoutanyRegulatoractorinvolvement)

whichshouldleadtoafurtherfrequencymitigationcouldbeadoptedwiththefollowingtwosteps:a. ThereadingoftheBeforeTake-Offchecklist“Abovetheline”,shallbepostponedattheholdingpoint,

aircraftonparkingbrakeandonlyafterhavingimplementedallmodificationsfornewTODCrelatedtoRunwaydepartingpositionandWeatherchange.MovingascloseaspossibletotheTopEventthemostpowerfulbarriersinplace(SymbolicRS-02,EP-01asneitherFunctionalnorPhysicalexist)canbetheanimmediateeffectivecountermeasure.

b. Duringsuchreadingandonlyafterhavingcompliedwith“FCTMPR-NP-SOP-70-00016299.0001001(Take-Offdata)”and“OMPartBPRO-NOR-SOP-10-A-00010248.0001001(Take-Offdata/Conditions)”PMchallengesTake-OffDataCard(Speeds,FlapseFlex)physicallykeepinginhandTODC,whilePFrespondingandvisuallycheckinginFMGC-MCDUPerformancepageandFlapIndication/Lever.

1FLIGHTWARNINGCOMPUTER(FWC)STDH2F9DINTRODUCTIONThe“F/CTLFLAP/MCDUDISAGREE”ECAMcautionisaddedforflightcrewawareness.Thiscautionistriggeredinphase2whentheT.O.CONFIGTESTpushbuttonispressed,orinflightphase3,iftheFLAPSleverpositionandtheFLAPSpositionenteredintheFMSaredifferent.

erroneous flaps selection at rwy holding point€¦ · linkedin.com: augusto claudio derghi cge...

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