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MaintenancemanagementMaintenancemanagement•Theapplicationof“on-condition”maintenancetomodularenginehasshownthatenginereliabilityismoresensitivetomaintenancemanagementpoliciesandmethodsthanunderafixedoverhaullifeconcept.•Toenabletheoperatortorealisethepotentialreliabilityandlowestoperatingcostofaengine,ajointlyagreedairline/manufacturerEngineManagementprogrammedefinesthemaintenanceaction.EnginemanagementEnginemanagement•Howtomaintaintheengine?•ExampleofRolls-Royceenginemanagementprogramme:–Differentmaintenancelevels–ModulesofttimeEnginemanagementModulesofttimeTomaintainenginereliability–Softtimeisthemoduletimesinceneworsincelastrefurbishmentabovewhichthemoduleistoberefurbishedwhentheengineisintheshop–Softtimeisnotamoduletimelimit–Itisaminimumtimeforrefurbishmentandassuchnearlyallmoduleswillexceedit.–softtimeisaconvenientconceptformanagingamodularengine.Itrationalisesworkscopedecisionatengineshopinductionandalsoallowsfullmodularinterchangeability.Thatmeansthatallmodulesleavethemoduleshopsuitableforfitmenttoanyengine.Enginemanagement•ModuleMaintenanceLevels:–Level1:serviceabilityinspection.–Level2:checkandrepair.–Level3:fullrefurbishment.EnginemanagementEnginemanagement•Level1serviceabilityinspection–ListsminimumworktobecarriedoutEnginemanagement•Level2checkandrepair–Applicabletomodulesbelowlevel3softtimeandscheduledtobedisassembledfor•Repair•Modification•Performancerecoverywork–ProvidesopportunitytocheckitemswheredisassemblyhasgivenaccessEnginemanagement•Refurbishment:–Coveringrepairorreplace,specialchecks,refitlives,keymodificationsandperformancerestoration.Itreferstothemanualsandotherpublicationsfordetailmethodsofrefurbishing.–Tooptimiseengineon-winglifeandcostofoperation–Moduletimesincerefurbishmentisre-settozeroforsoftlifepurpose.Enginemanagement•Level4overhaul(level4softtime)–Applicabletomodulesabovelevel4softtime–Definescompletedisassemblyofthemodulefor•Cleaning•Inspection•Cracktest•Repair–Examinationfor•Cracks•Corrosion•Clearfluidpaths–Moduletimesincere-settozeroforsoftlife.EnginemanagementEMPPart1CustomisedforeachoperatorEnginereferenceinformationAircraftcheckintervalsModulesofttimeKeyservicebulletinsExceptionstopart2Part2Non-customised–applicabletoalloperatorsNMSB,NTOandOINlistOn-winginspection&maintenancerequirementsEngineshopinductionreqirementsMinimumrefurbishmentspecificationEnginemanagement•EMP:apartfromsofttime,thekeythingsofEMParefollowings:–ReliabilityandEMPreview•Operator+RR•Reviewoperator’sproblems,disruptionsandremovalcauses•Theoperator’sandoverhaulagency’sshopvisitpractices,anynotableshopinspectionfindings,fleetexperience•Performanceanalysisandfailureanalysisdonebytheoperator•Anyspecialrequirementsfromtheoperator–Theresultofthemeeting:•FormaEMPbook.Enginemanagement•EMPbookcovers:–On-wingmaintenance,moduleandaccessoryunitsofttimes,lifesamplingandrefurbishimentspecifications.–Theprocedureswhichapplyatanengineshopvisit,andtheengineinspectionandtechnicalreviewcommitteerequirementstoensurethatthemostcosteffectiverefurbishementpackageisspecified–Therefurbishmentspecificationscoverrepairorreplacedecisions,specialchecks,refitlives,keyMod.andperformancerestorationguidance–ShopvisitforecastingEnginemanagement•Whatisanenginemanagementprogramme?–AnEMPisanadvisorydocument,complementarytothemaintenancemanuals,enginemanualsandMRBdocumentwhichremaintheexecutivedocuments.–AnEMPdefinesapackageofon-wingandin-shopmaintenanceandrepairprocedurestominimiseservicedisruptionandachieveoptimumreliabilityandcostofownership–ItinitiallydrawsondevelopmentenginetestingandexperienceinsimilarRB211engineoperationswhichissubsequentlyamendedtotakeoperatorsandworldwideexperienceintoaccount–TheEMPisreviewedregularlyandjointlyagreedbetweentheairlineandRR–TheoperatormayelecttousetheEMP,inwholeorinpart,intheirsubmissionofamaintenanceplantotheairworthinessauthority.Enginemanagement•EnginerefurbishmentworkscopeassessmentEnginemanagement•Factorsaffectingchoiceofsofttime–Modulelifeexpectancy–Performancerestorationbenefits•Fuelburn•Hotsectionlife–Specificproblemareasfromserviceanddevelopmentexperience.•Refurbishtoextendcomponentlife/reduceon-wingmaintenanceect.–Enginemodificationstatus•LowsofttimeaccelerateskeymodincoprorationEnginemanagement•Modulesofttimeexamples:•ModulelifeexpectancyandotherfactorssofttimeHrs•LPfanveryhighFODresistance8000•IPcompressorHighperformance6000•Intermediatecasehigh8000•HPsystemmoderate/mostarduousduty5000•IPandLPturbinehigh/hotenvironment6000•HSgearboxhigh8000Enginemanagement•Factorsaffectingsofttimes:–Themoredurablethemodule,thehigherthesofttime–Performancerestorationgivesbenefitsintermsoffuelburnandhotsectionlife,thepaybackisloweringthesofttime.–Highsofttimeleadstothe“modularenginetrap”•Poorreliability•Highcostofownership–Lowsofttime=lowshopvisitrate=lowcost.EnginemanagementEnginemanagement•Bymaintenancemanagement:–Increasingengineonwinglife–Reducingdisruptioncosts–Reducingsparesholdingsorinventorylevels–Reducingmaintenancemanpower–Increasingengineavailability–Improvingreliability–Assistsforwardplanning