Human factors[人为因素].ppt

,PRESENTEDBYCOSCAP-SA,Humanfactors,Isnotjustaboutpeople:itisalsoaboutimprovingsystems.,HUMANFACTORS,Threatstotheairworthinessofanaircraft?Mostpeoplewillagreethatthethreatstotheairworthinessofanaircraftare:metalfatigue,corrosion,excessivewearofcomponentsorotherresultsofageinganduse.,HUMANFACTORS,Yetaircraftarebecomingincreasinglyreliable,theactionsofthemaintainersthemselveslieattheheartofmanyairworthinessproblems.AccordingtoBoeing,around15%ofmajoraircraftaccidentsinvolvemaintenanceerror.,HUMANFACTORS,Humanerrors-powerfulforcesaffectingthequalityofmaintenance,Producedby:frustration,sleepiness,misunderstandingsandmemorylapses.Thispresentationdealswithjustafewoftheseissues.,HUMANFACTORS,Maintenanceerrorshaveasignificantimpactonsafety,butalsoonthefinancialperformanceAsingleinflightturn-backofaBoeing747,withtheneedtoaccommodatepassengersovernight,cancost$250,000heUSA,maintenanceerrorcouldcostairlinesonebillionUSdollarsperyear!,HUMANFACTORS,Thetermhumanerrorisusedinrecognitionofthefactthatmostaviationaccidentsdoinvolvehumanerroratsomepointinthechainofevents.theseerrors(orunsafeacts)tendtobejustonelinkinachainofevents.,HUMANFACTORS,ReasonmodelAusefulframeworktousewhenconsideringhumanfactorsissuesistheReasonmodelofaccidentcausation,HUMANFACTORS,Unsafeactsproblemsintheirownright,butalsosymptomsofwiderproblems.,HUMANFACTORS,WiderProblemsItwasneverestablishedwhohadmadetheerrorsthatculminatedintheaccident;however,findingthepeopleresponsiblemaynothavehelpedpreventfutureaccidents.Themostimportantlessonslearntfromthisaccidentwerenotaboutindividuals,butaboutthewaymaintenancewasorganisedandcarriedout,HUMANFACTORS,TheNTSBidentifiedarangeofsystemproblemserror-producingworkenvironment,potentiallydangerousscaffolding,poorlighting,inappropriatestorageofparts,alackoftrainingincompanymaintenancepoliciesandinadequateoversightbytheFAA.,HUMANFACTORS,upstreamproblemsAddressingeachoftheseupstreamproblemswouldnotonlyreducethechanceofthesameerrorshappeningagain,butshouldalsohelptopreventahostofotherqualityproblems.2,HUMANFACTORS,Unsafeacts:Whatgoeswrong?Inordertounderstandthetypesoferrorsmadebymaintenanceengineers,the(Australian)BureauofAirSafetyInvestigation(BASI)hascollectedinformationonover120maintenanceunsafeactsfrominterviewswithairlineengineeringpersonnelandfromincidentreportsreceivedduringastudyoftheregionalairlineindustry.Over80%oftheunsafeactsofmaintenancemechanicsfellintooneoffivetypes.,HUMANFACTORS,HUMANFACTORS,Memorylapse:24%Memorylapsesdonotgenerallyhappenrandomly,butoftenoccurwhenapersonisinterruptedtogoanddosomethingelse.Jugglingmaintenancetasksonseveralaircraftisacommonsituationwhichcanleadtoamemorylapse.,HUMANFACTORS,2.Work-arounds:23%work-aroundsinvolveperformingataskwithoutallthenecessaryequipment,orinamoreconvenientmannerthanapprovedprocedures.However,somearemoreserious,asinthecaseofworkersfacedwithtimepressurewhodecidenottodocumenttheiractionsordecidenottoperformalltherequiredstepsinatask.Ontheirown,work-aroundsmaynotnecessarilyresultinanincident,butseriousproblemscanresultwhenotherpeoplearenotawarethatsomeonehastakenashortcut,orwhenawork-aroundisfollowedbyanerror.,HUMANFACTORS,Work-arounds-CommentMaintenancemechanicsareoftenfacedwiththepressureofbeinginformedbycompaniestofollowtheprocedures,butatthesametimeareencouragedtogetworkdonetodeadlines.Onemechanicsummeditupthisway:Managementtellustofollowtheprocedurestotheletter,butthentheytellusnottobeobstructiveandtousecommonsenseArecentEuropeanstudyfoundthatathirdofmaintenancetasksinvolvedadeviationfromofficialtaskprocedures.3,HUMANFACTORS,Situationalawareness:18%Situationalawarenesserrorsoccurwhenthemechanicstartsworkwithoutfirstgaininganaccuratepictureofthesituationbeingdealtwith.Often,theydontrealisethatthesituationisdifferentfromnormal,aswhenamechanicactivateshydraulicswithoutnoticingthatcockpitcontrolshavebeenmovedwhilethehydraulicswereoff.Inothercases,anengineermaynotbeawareofworkbeingdonebyotherworkersonthesameaircraft.,HUMANFACTORS,4.Expertise:10%Maintenanceengineersareliketorquewrenches:theyneedtobere-calibratedfromtimetotime,HUMANFACTORS,4.Expertise:10%Errorsofexpertisehappenwhensomeonedoesnthavetheknowledge,skillsorexperiencetodoallaspectsoftheirjob.Asmightbeexpected,errorsofexpertisetendtoinvolvelessexperiencedworkers.Thefactthat10%oferrorsareofthiskindcouldindicatedeficienciesintraining.,HUMANFACTORS,Actionslips:9%Actionslipsoccurwhensomeoneaccidentallydoessomethingunintentionally.Slipstendtooccuronroutine,highlyfamiliartasks.,HUMANFACTORS,Localproblems:Whydothingsgowrong?TheBASIanalysisofmaintenanceincidentreportsfoundthatforincidentswhichhadairworthinessimplications,themostcommonfactorsintheworkareaatthetimeoftheincidentwere:,Confusionormisunderstandingsaboutprocedures,Workershaveafairlylimitedunderstandingofacompanysformalpoliciesandprocedures.Theyfollowinformalpracticesdevelopedonthejob.Older,experiencedworkerswillsometimesdeveloptheirownpractices,whichmaybedifferentfromtheapprovedprocedures.Unworkableorinconvenientproceduresalsopromptthesortofwork-aroundsdescribedearlier.,Communicationbreakdowns,Inarecentsurvey,seniorUSmaintenancemechanicswereaskedtodescribethemostchallengingpartoftheirjob.Theirmostcommonanswerwashumanrelationsordealingwithpeople4Performinginateamrequiresmorethantechnicalknow-how,andweoftenoverlooktheneedtodeveloptheseimportantcommunicationandpeopleskills.,3.Pressureorhaste,operatorsstrivetoreducemaintenancedowntime,pressureisafactoflifeformaintenanceengineers.engineersfacedwithrealorself-imposedtimepressureswillbetemptedtotakeshortcutstogetanaircraftbackintoservicemorequickly.,Pressureorhaste-SystemSafeguards,Maintenancesystemshavebuilt-insafeguardssuchas:suchasindependentinspectionsandfunctionaltestsdesignedtocaptureerrorsoncriticaltasks.Bynecessity,theseerror-capturingsafeguardsoccurattheendofjobs,atexactlythetimewhenpressurestogettheaircraftbackintoservicearelikelytobegreatest.,IntherecentBASIsurvey,32%ofmechanicsreportedthattherehadbeenanoccasionwhentheyhadnotdonearequiredfunctionalcheckbecauseofalackoftime.Atthetime,suchadecisionmayhaveseemedsafeandreasonable;however,decisionsmadeunderpressuredonotalwaysstandthetestofhindsight.,4.Inexperience,Youngerpersonnelneedtoknowaboutthetrapslyinginwaitforthem,yettoooftentheyareallowedtodiscovertheseforthemselves.,5.Alackoftools,orequipment,orspares,Manywork-aroundsoccurinresponsetoalackofappropriatehardwareorspares.Itisunderstandablethatairlineswilltrytoreducetheirstocksofexpensivespares;however)insomecasesrelativelyinexpensivesparessuchas0-ringsarenilstockitems.Furthermore,alackofmajorsparescanleadtoincreasedcannibalisationofpartsfromotheraircraft,whichinturndoublesthedisturbancetosystemsandincreasesthepotentialforhumanerror.,traininginhumanfactors,maintenancepersonnelmayneedtraininginhumanfactorsareassuchas:communication,supervision,anddealingwithpressureandfrustration.,benefitofhumanfactorstraining,Thegreatbenefitofhumanfactorstrainingisnotonlythatpeoplechange,butthatpeoplecanseetheopportunitiestochangethesystemsinwhichtheywork.Forthisreason,managers,whohavethemostpowertochangethings,shouldnotbeexcludedfromhumanfactorstraining.,Organisationalfactors:,WhataretheweaknessesIntheoverallsystem?Maintenanceincidentscanreflectarangeoforganisationalproblems.Threeofthemostimportantofthesearedealtwithonthefollowingslides.,1.Lackofrefreshertraining,Moststatesregulationsrequirethatmaintenancepersonnelreceivepropertraining.However,inreality,fewmaintenanceengineersreceiverefreshertrainingoncetheyhavegainedtheirlicences.Withoutsuchtraining,non-standardworkpracticescandeveloporengineerscanlosetouchwithchangesinregulationsorcompanyprocedures.,2.Lackoflearningfromincidents,Theconventionalwisdomamongsafetyexpertsisthatforeveryaccidenttheremaybe30ormorepreviousminorincidents.WhenBASIinterviewedmaintenanceengineersaboutincidents,itbecameapparentthatbeforeaseriousqualitylapseoccurs,thereareusuallyearlierincidentswhichcouldhaveactedaswarningsofaproblem.,Lackoflearningfromincidents,Unfortunatelywedonotalwayslearntherightlessonsfromthesewarningincidents;sometimesbecausetheyareneverreported.Itisnevereasytoadmitamistake;however,itisevenharderwhenanorganisationpunishespeoplewhomakehonestmistakes.Apunitiveculturewithinthecompanyortheregulatoryauthorityplacesbarriersinthewayoflearningfromourmistakes.,Lackoflearningfromincidents-Action,Oneactionwhichmanagerscantaketoensurethattheyhearaboutthewarningincidentsistohaveaclearresponsibilitypolicy;whichoutlineshowtheorganisationwillrespondtomaintenanceincidents.Figure2illustrateshowaresponsibilitypolicymightwork,althougheveryoperationwillneedtotailorsuchapolicytoitsownrequirements.Needlesstosay,nopolicysuchasthiscanbeexpectedtofunctioniftheregulatoryauthoritypenalisesthosewhoreporttheirmistakes.,RESPONSIBILITYPOLICY,Lackoflearningfromincidents-Action,Onceanincidenthasbeenreported,thefocusofaninternalinvestigationshouldnormallybeonidentifyingsystemproblems,notonidentifyingpersonaldeficienciesofindividuals.Theremayberaretimeswhenincidentsarerelatedtointentionalactsofmalice,butmostincidentsreflectsystemproblemswhichgobeyondindividualworkers.Aninternalinvestigationthatonlyresultsinrecommendationsdirectedatthelevelofindividuals,aresuresignsthattheinvestigationdidnotidentifythesystemfailureswhichledtoanoccurrence.,FATIGUE,Maintenanceneedstobedoneatnight;fatiguelevelsshouldbemanaged.almostallnight-shiftworkerssufferfromalackofqualitysleep.After18hoursofbeingawake,mentalandphysicalperformanceonmanytasksisaffectedasthoughthepersonhadabloodalcoholconcentration(BAC)of0.05%.,FATIGUE,Boringtaskswhichrequireapersontodetectarareproblem(likesomeinspectionjobs)aremostsusceptibletofatigueeffects.After23hoursofbeingcontinuouslyawake,peopleperformasbadlyonthesetasksaspeoplewhohaveaBACof0.l2%.8,FATIGUE,Manyengineersclaimedtheyhadworkedashiftof18hoursorlongerinthelastyear,withsomehavingworkedlongerthan20hoursatastretch.Thereislittledoubtthatthesepeoplesabilitytodotheirjobwouldhavebeendegraded.Animportantpointtonoteisthatlikepeoplewhoareintoxicated,fatiguedindividualsarenotalwaysawareoftheextenttowhichtheircapabilitieshavedegraded.,FATIGUE,Atatimewhenthedangersoffatiguearebeingrecognizedinareasasdiverseasmedicineandroadtransport,wemustaskwhytherearenoregulationsinmanystatestocontroltherisksoffatigueamongaircraftmechanics.,SAFEGUARDS,ReducingtheconsequenceofmaintenanceerrorMinimisingtheconsequencesoferrorsVSworkingwithoutnetsFunctionalchecksandindependentinspectionsareexamplesofsafeguardsdesignedtocaptureerrorsbeforetheycauseharm.,SAFEGUARDS,Thereisanotherapproachtomanagingerror.Acknowledgethaterrorswilloccure,designproceduresandsystemsthatcanminimisetheconsequencesoferrors,SpecialmaintenanceprecautionsappliedtoETOPSareanexampleofsuchanapproach,SAFEGUARDS,theseprecautionsshouldalsobeappliedtoaircraftwithmorethantwoengines,ortotwin-engineaircraftwhicharenotbeingmaintainedinaccordancewithanETOPSmaintenanceprogram.,Example,Forexample,in1995,aEuropean-operatedBoeing737-400wasforcedtodivertshortlyafterdeparturefollowingalossofoilquantityandpressureonbothengines.BothoftheaircraftsCFM-56engineshadbeensubjecttoboroscopeinspectionsduringthenightpriortotheincidentflight.High-pressurerotordrivecoverswerenotrefittedoneachengineandasaresult,nearlyalltheoilwaslostfromtheenginesduringthebriefflight.9,CONCLUSIONS,Unfortunately,advancesinaviationtechnologyhavenotnecessarilybeenmatchedbyimprovementsinthewayweorganisetheworkofthepeoplewhomaintainaircraft.,CONCLUSIONS,Maintenanceincidentssharesimilarfeatures.Arelativelylimitednumberofunsafeacts,suchaswork-arounds,memorylapsesandsituationalawarenesserrorstypicallyoccurinthecontextofproblemssuchasunclearorpoorprocedures,alackofequipmentorspares,communicationbreakdowns,timepressureandfatigue.,CONCLUSIONS,Becauseunsafeactsaregenerallysymptomsofwiderproblems,humanfactorsisnotjustaboutfocusingonpeoplebutonthesystemswithinwhichpeoplework.,CONCLUSIONS,Thisarticleconcludeswithjustfivesystem-levelimprovementsthatmayhelptoensuresafermaintenance:1.Introducerefreshertraining,particularlyoncompanypoliciesandprocedures.2.IntroduceaclearResponsibilityPolicytoremovebarriersthatdiscouragepeoplefromreportingincidents.,CONCLUSIONS,3.Introduceafatiguemanagementprogram.Thiswillalmostcertainl