Rolls-RoycePOBox31,DerbyDE24BBJ,EnglandTelephone:+44(0)1332242424Fax:+44(0)1332249936WNW.rolls-royce.comPetitionforExemptionfrom14C.F.R.§33.27(f)(6)tAmendment31A.Name,AddressandContactInformationofthePetitionerRichardShepherd-AirworthinessSpecialistML-52Rolls-RoycepicPOBox31DerbyDE248BJEnglandTel:(+44)1332249905richard.shepherd@rolls-royce.comB.PertinentSectionoftheCodeofFederalRegulationsRolls-Royceherebypetitionsforanexemptionfrom14C.F.R.§33.27(f)(6).ThisexemptionisrequestedfortheHPshaftsystemonly,fortheTrentXWBenginemodelsidentifiedinSectionCbelow.Thepertinentprovisionsof14C.F.R.§33.27are:14C.F.R.§33.27Turbine,compressor,fan,andturbosuperchargerrotoroverspeed.(f)Failureofashaftsectionmaybeexcludedfromconsiderationindeterminingthehighestoverspeedthatwouldresultfromacompletelossofloadonaturbinerotoriftheapplicant:(6)Doesnotexcludethe entireshaft.C.TheExemptionbeingsoughtRolls-Roycerequestsanexemptionfrom14C.F.R.§33.27(f}(6)fortheHPshaftsystemofthefollowingTrentXWBenginesmodels:ModelTrentXWB-84TrentXWB-798TrentXWB-79TrentXWB-75Ratingx1000lbs.84797975Noexemptionissoughtforothershaftsystemsonthese,oranyother,enginemodels.TheHPshaftsystemwillcomplywith§33.27,subjecttothegrantingoftheexemptionfrom§33.27(f)(6)requestedherein.Relieffrom§33.27(f)(6)issoughtbecauseanalysishasfailedtoshowthatfailureoftheHPshaftsystemcanneverresultinoverspeedtoburst.ThedesignoftheHPshaftsystemisnotamenabletoanalysisbyshaftsection.Rolls-Roycethereforeseeksanexemptionfrom§33.27(f)(6)toexcludetheentireHPshaftsystemfromconsiderationindeterminingthehighestoverspeedthatwouldresultfromacompletelossofloadonaturbinerotor.However,asdemonstratedinSectionEbelow,thelevelofsafetyaffordedbycompliancewith§33.27fortheHPshaftsystemwillbeunaffectedbythegrantingofanexemptionfrom§33.27(1)(6).Insum,Rolls-Royceisrequestingthisexemptionbecausecompliancewith§33.27cannotbeshownabsentanexemptionfrom§33.27(f)(6).However,compliancecanbeshown,withatleastanequallevelofsafetytothatrequiredtomeet§33.27,iftheexemptionisgranted.Rolls·RoycepicRegisteredofflce:65BuckinghamGate,LondonSW1E6ATCompanynumber:1003142.RegisteredInEngland.Page1Rolls-RoyceThisexemptionisbeingsoughtbecausecompliancewiththerequirementofexemptionNo.11075datedOctober3,2014)to§33.27(b)(3)forTrentXWB,thatthereshouldbepositiveburstmargin,cannotbeprovedforalloperatingconditions.Noexemptionto§33.27(b)(3)isneededshouldtherequestedexemptionto§33.27(f)(6)begranted.StatementofPublicInterestGrantingthisexemptionwillpromoteandservethepublicinterestbecause:a.Thestate-of-the-artenginemodels(andtheHPshaftsystem)atissueinthispetitionrepresentthelatestgenerationofenginesandenginetechnologyfromtheTrentenginefamily.TheTrentlineofengineshas'establishedanoutstandingtrackrecordofperformanceandsafetyover41yearsandmorethan265millionserviceflighthours.Thus,theenginemodelsandshaftsystematissueinthispetitionarebasedonprovenexpertiseandin-service-verifieddesignstylesandpractices.Thisexperienceandtrackrecordhelpstoensurethereliabilityandsafetyoftheproduct.Asexplainedfurtherinthepointsimmediatelybelow,theintroductionoftheseenginemodelsintoservicewillgeneratevaluablepublicbenefits.b.Thegrantingoftherequestedexemptionwillexpeditetheentryintoserviceofsuperiorenginesandenginetechnologythatwillenhancethesafetyandreliabilityofairlineoperations,andincreasetheefficiencyofaircraftperformance,therebypromotingU.S.economicinterests(includingthoseofU.S.airlines,andtheiremployeesandshareholders)aswellasthoseofthetravellingpublic,whilealsoreducingadverseeffectsontheenvironmentrelativetoolderenginetypesonotheraircraft.Alloftheseenhancementsconstitutesubstantialpublicbenefitsc.Thesestate-of-the-artenginemodelswillreducetheoperatingcostsofaircraft,andtheairlinesthatoperatethem,relativetocostsassociatedwithaircraftthatarecurrentlyinservice.SuchareductioninoperatingcostswillbenefitU.S.andinternationalairlines,theiremployeesandshareholders.Moreover,suchreducedoperatingcostsprovidetheopportunityforairlinestooffermoreandlessexpensiveairserviceoptionstothetravelingpublic.d.Thesestate-of-the-artenginemodels,includingtheproposedmodifications,whenoperatedintheAirbusA350,willreducefuelburn,therebyreducingharmfulemissionssuchascarbondioxide(C02)andNOxfromlevelsexperiencedwithotherolderenginetypescurrentlyinserviceonotheraircraft.e.Thesestate-of-the-artenginemodels,includingtheproposedmodificationsmakeadditionalaircraftmodelsavailableforpurchasebyU.Sairlines.SuchchoicesareintheeconomicinterestoftheU.Sthroughpromotionofamorecompetitivemarketforlargecommercialtransportaircraft.f.TheTrentXWBmodelswillbeinstalledontheAirbusA350,whichhascustomersbothwithinandoutsidetheUnitedStates.g.TheTrentXWBisbuiltwithU.S.suppliedpartsthatconstituteapproximately16%oftheenginevalue.SalesoftheenginecontributetotheU.S.economy,supportU.S.jobs,andenhancetheU.S.balanceoftradeandgrossdomesticproduct,allofwhichpromotetheU.S.publicinterestRolls-RoycepicRegisteredoffice:65BuckinghamGate,LondonSW1E6ATCompanynumber:1003142.RegisteredInEngland.Page2Rolls-Royceh.MaintainingapprovaloftheseTrentXWBenginemodelsintheU.S.promotestheregulatorystandardsoftheU.S.asaglobalbenchmarkforairworthiness.PromotionoftheU.S.regulatorystandardsisinthepublicinterestasthisincreasesthenumberofgoodsandservicesavailabletoU.S.citizensthatarecompliantwiththeU.S.regulatorystandards,andsincemanycountriesvoluntarilyadoptU.S.standardsthisprocessdoesnotincreasetheburdenontheU.S.government.D.StatementofnoAdverseEffectonSafetyTheFAA'sgrantofthisrequestedexemptionwillhavenoadverseeffectonsafety.Compliancewith§33.27issignificantforsafetypurposesbecauseitdemonstratesthatanengine'srotorswillnotfailunderavaryingrangeofpotentialoperatingconditions.Therequirementscontainedin§33.27(f)aresignificantforsafetybecausethissubsectionallowsfailuresofshaftsectionstobeexcludedfromtherangeofconditionsconsideredunder§33.27,butonlyifadesign_organizationcandemonstratethattheriskofsuchshaftsectionfailuresissufficientlyremote.Subsection33.27(f)(6)doesnotinitselfimposeanyadditionalsafetyrequirement.Clearly,ifriskoffailureofthewholeshaftsystemisconsideredandshowntobeatleastasremoteasisacceptablefor"shaftsections,"thentheoveralllevelofsafetymustbeatleastequaltocircumstancesinwhichonly"shaftsections"areconsidered,asprovidedforunder§33.27(f).Subsection33.27(f)(6)wasincludedinSection33.27basedonahistoryoffailuresassociatedwithconventionalshaftsystems,whichraiseddoubtabouttheabilityofdesignorganizationstofullyassessthepotentialfailuremodes(andfailurerate)ofanentireshaftsystem.However,fortheHPshaftsystemoftheTrentXWB(andindeedforotherRolls-Roycemodern3shaftengines),thisanalysiscanbecarriedoutwithhighfidelitybecause:a.TheHPshaftsystemdesignutilizedacrosstheTrentenginefamilydifferssignificantlyfromconventionalshaftsystems.Forexample,itfeaturesnobearingsoroilsystemcomponents,hashighstiffnessandsignificantclearancerelativetoothershafts;consequently,thethreatsassociatedwiththefeaturesofaconventionalshaftdonotapply.AFailureModeandEffectAnalysishasdeterminedthattherearenoknownorpotentialenvironmentalthreatstotheintegrityoftheHPshaftsystemcomponentsthatcouldleadtoalossofloadfailure.b.Inordertoensureahighlevelofintegrity,thespecialcontrolsappliedtothetorquetransmittingcomponents(i.e.,theHPCompressorRearDrumandtheHPTurbinediscoftheHPshaftsystem)areofahigherstandardthanthoseofmanyothershaftsystemsinthepast.Thesemandatedcontrolsaddress,butarenotlimitedto:1.Materialspecifications;2.Materialproperties(e.g.,lowcyclefatigue,highcyclefatigue,creep);3.Manufacturinginducedanomalies;4.Serviceinduceddamagetoleranceassessment;5.Safelifemandatoryinspections;and6.Mandatorycyclelifelimitation.c.Thetheoreticalassessmentofpoints1)and2)aboveissupportedbytheserviceexperienceoftheRolls-Roycethreeshaftfamilyofengines,allofwhichincorporatethesamedesignstylefortheHPshaftsystemastheTrentXWBenginemodelsthatarethesubjectofthispetition.Overthecourseofmorethan265millionserviceflighthours,therehavebeennofailuresoftheHPshaftsystemtorquepathontheTrentfamilyofengines.Thisperformancereflectsanextremelyremotepotentialfailurerateoflessthan2.6x10-9failuresperflighthour.Insum,thereisampleevidencethatanalysisofthecompleteHPshaftsystemontheTrentXWBmodelsatissueachievestheleveloffidelityrequiredforfailuresofshaftsectionsunder§33.27(f).Therefore,thelevelofsafetyundertherequestedexemptionwillbeatleastequaltothatotherwiseprovidedby§33.27,therebyassuringthatnoadverseeffectonsafetywillresultfromagrantoftherequestedexemption.·Rolls-RoycepicRegisteredoffice:65BuckinghamGate,LondonSW1ESATCompanynumber:1003142.RegisteredinEngland.Page3Rolls-RoyceE.SummaryforFederalRegisterInaccordancewith§11.81(f),Rolls-RoyceoffersthefollowingsummarysuitableforpublicationintheFederalRegister.Petitioner:Rolls-RoycepicSectionof14C.F.R.Affected:14C.F.R.§33.27(f)(6)DescriptionofReliefSought:Rolls-Roycerequestsanexemptionfrom14C.F.R.§33.27(f)(6)tobeappliedtoRolls-RoyceTrentXWBenginemodelsTrentXWB-84,TrentXWB-798,TrentXWB-79andTrentXWB-75.Rolls-RoyceseekstoexcludetheentireHPshaftsystemfromconsiderationindeterminingthehighestoverspeedthatwouldresultfromacompletelossofloadonaturbinerotor.F.AdditionalSupportingInformationEASACertificationrequirementsCS-E840andCS-E850aresimilarrequirementstothoseof§33.27.TheexistingTrentXWBenginemodelshavebeenpreviouslycertifiedbyEASAunderTypeCertificateE.111.TomeettherequirementsofCS·E840andCS-E850,EASAgrantedanEquivalentSafetyFinding.TheevidenceprovidedtosupportthisEquivalentSafetyFindingwassimilartothatprovidedinthispetitionforexemption.TheEquivalentSafetyFindingwasacceptedbyEASAonJanuary15th,2013.G.PrivilegesofthisExemptionOutsidetheUnitedStatesPer14C.F.R.§11.81(h),Rolls-RoycerequeststhattheprivilegesofthisexemptionbeextendedoutsidetheUnitedStates.ThisextensionofprivilegesisnecessaryforoperationsbasedwithinforeigncountrieshavingbilateralagreementswiththeUnitedStatesacceptingFAA14C.F.R.Part33astheirairworthinessstandardsfortransportcategoryaircraft.TheTrentXWBisintendedfortheglobalmarketplace,withcustomersbasedincountriesutilizingtheU.S.airworthinessstandards.H.GoodCauseexiststoissuetheExemptionwithoutNoticeorCommentPursuantto14C.F.R.§11.87,Rolls-RoycerequeststhatthispetitionbeprocessedwithoutpublicationintheFederalRegisterfornoticeandcomment,asmayotherwiseberequired.Rolls-Roycebelievesthatgoodcauseexiststonotdelaythisactionbecause:a.thereliefrequestediseffectivelyidenticaltoanEquivalentSafetyFindingpreviouslyacceptedbyEASAb.delayingtheactionwouldadverselyaffectRolls-RoycebecausetheTrentXWBenginemodelscoveredbythispetitionarecurrentlyinserviceoperationandfuturemodificationofthedesignwillberequiredtoaddressserviceissuesandmaintainreliabilityandmaintainthecompetitivenessoftheproduct.;andc.thispetitionistimelyfiled.Respectfullysubmitted,RichardShepherdAirworthinessSpecialistRolls-RoycepicDate;23mDecember2015Rolls-RoycepicRegisteredoffice:65BuckinghamGate,LondonSW1ESATCompanynumber:1003142.RegisteredInEngland.Page4