航空公司運營與管理（學生）英文課件chapter5

DelayManagementandDisruptionManagementOutline1.airlinedisruptionmanagement2.on-timeperformancemeasurementandstatisticsreporting3.inherentdelayofanairlinenetwork4.scheduleoptimizationandnetworkreliability1.airlinedisruptionmanagementAirlineOperationCentre(AOC)AOCcentrallymanageoperationaldisruptionthatmayoccurinday-to-dayoperationsandprovidevariousunitsofanairlinewithtacticaldisruptionrecoveryplans.ThemajorfunctionofanAOC,besidesoverseeingdailyoperations,istoco-ordinaterecoveryactionsamongdifferentunitswithinanairlinesuchascrewing,ticketingandmaintenanceby“optimally”allocatinglimitedoperationalresources,whileminimizingextraoperatingcostsduetodisruptingrecovery.Dependingonthescaleofdisruptions,therearedifferentrecoverytactics.Minordisruptionsrefertothoseonesthatcauseinitialdelaylessthananhour,whilemajordisruptionsrefertothecasesinwhichflightsaredelayedforlongerthananhour.1.1MinordisruptionsandrecoverytacticsAirlineoperationsaresubjecttostochasticdisruptionsduetovariousreasonssuchasweatherconditions,equipmentreadiness,passengerhandling,andaircraftturnaroundprocedures.Mostdisruptingeventsonlycause“minor”delaytocertainoperatingtasks,anddonotnecessarilycauseflightdeparturedelays.Flightdelaysonlyoccurwhendelayscannotbeabsorbedbythebuilt-inschedulebuffertime.Flightdelaysmaypropagateinanairlinenetworkduetoresourceconnections.Inthesimilarminordisruptionscenario,airlineswhichoperatepoint-to-pointnetworkshavelittle(ornone)issueswithpassengerre-accommodationduetomissingconnectingflights.Nevertheless,crewingandaircraftroutingplansinapoint-to-pointnetworkarestillaffectedandforsomecases,areaffectedmoreseriouslyduetothetightresourceconnectionsinapoint-to-pointnetwork.Regardingtherecoveryofpassengeritinerary,airlineusuallyofferdelayedpassengerscompensationsuchasmealvouchers,ifdelaysareduetotheairline’sownoperations.Regardingtherecoveryofoperationalplansofcrewingandaircraftroutingbyairline,thereareanumberoftacticsadoptedbyAOC.First,“doing-nothing”isalwaysanoptionforminordisruption.Buffertimeexistsinthegroundtimeforturningaroundanaircraftaswellasintheairbornetimeforflightoperations.Second,twowidelyusedtacticsare:(1)speedupaircraftturnaroundoperations;and(2)speedupenrouteflightoperations.Turnaroundoperationscanbespeededupbyallocatingmoregroundstaff,moreequipment,andbyomissionordelayofcargoloads.Speedingupanaircraftduringenrouteoperationcansaveondelaytimealreadyaccumulated.However,thecostoftheextrafuelburntduetohighercruisingspeedsmustoutweighthepotentialcostsduetodelays.Third,aircraftswapisachoiceinsuchasituation.Aircraftswapcanoccuratanairportifaninboundflightisdelayedandthereareotheraircraftatthesameairportthatareofthesameorsimilaraircrafttype.Thistacticisquiteoftendeployedbylow-costairlinethatoperateasinglefleettypeofaircraft.Somethingtorememberafterswappingaircraftbetweenroutesisthatanairlinemayalsoneedtoaltercrewingplansandaircraftroutingplansduetocrewingconstraintsandaircraftmaintenanceschedules.Nonetheless,inaminordisruptionsituation,aircraftareoftenswappedbacktotheoriginalroutedlateronthesamedayorthedayafter,soastominimizecostlyalternationtocrewingandmaintenanceschedules.1.2majordisruptionsandrecoverytacticsMajordisruptionstoairlineoperationsaremainlycausedbyinclementweathercondition,aircraftmechanicalfaults,delaysinairlineoperations,airlineresourcesshortage,andrareincidents.Inmajordisruptionssituation,schedulerecoveryissimilartothatunderminordisruptions.Passengerre-accommodationisparamountforairlinesduringmajordisruption.Airlinemustprovidepassengerswithmeals,refreshments,andaccommodation,alsotrytotransportthosepassengersbyalternativemeansincludinggroundtransport,flightsbyotherairlines,flightsbyotherroutesbetweenthesameorigin/destinationairport,andflightsscheduledatalatertime.Thegoalofaircraftrecoveryistolimittheimpactofdisruptionaswellasminimizethedisruptiontime.Someconstraints:(1)aircraftmaintenanceschedules;(2)airportoperationalconstraints;(3)aircraftflow“balance”attheendofdisruptionperiod.Thereareafewtacticsinrecoveringaircraftroutingbacktonormaloperatingschedules.(1)delayingflights;(2)flightcancellations;(3)aircraftferrying(flyinganemptyaircraftforrepositioningpurpose);(4)diverting(flyingtoanotherairport);(5)swappingflightsamongaircraftroutes.Crewdisruptionrecoveryisahighlycomplexissueforthreereasons.(1)crewcostsusuallyconstituteamajorpartofairlineoperatingcosts.(2)crewingissubjecttocomplexworkingrulesandsafetyregulations.(3)crewingishighlysynchronizedwithaircraftrouting.Crewrecoveryhasmultiplefacetstoconsidersuchasminimizingextracosts,minimizingcrewpairingdisruptionandaimingtoreturntonormaloperationassoonaspossible.Recoverytactics:(1)deployreservecrew;(2)deadhead(re-position)crew;(3)rebuild/swapcrewdutiesfordisruptedflights/crewmembers.1.3choosingrecoveryplansandconsiderationsAirlinedisruptionmanagementandschedulerecoveryischallengingduetothefollowingreasons.(1)anairlinescheduleisanongoingoperationwithvariousresourcesconnectedwithoneanother.(2)arecoveryplanoftenmustbegeneratedinarelativelyshorttimeframewithlimitedresourcesincludingreservedresourcessuchasreservedcrewandspareaircraft.(3)arecoveryplanisoftenguidedbyanobjectiveormultipleobjectivesindisruptionmanagement.Theyincludetheminimizationofpassengerrecoverycosts,minimizationofdisruptedtimeofairlineoperations,andminimizationofairlinecostsduetodisruptions.Often,someobjectivesconflictwitheachotherduetothenatureofresourceconnectionsandavailablerecoveryoptions.Forschedulerecovery,astowhichoptionischosenandimplementedtomitigateoperationaldisruptions,decision-makingmaydependonthefollowingconsiderations.(1)thenatureofdisruption,i.e.thelocation,fleettypes,timeofday,andseverity,determinesthepotentialimpactofaspecificdisruptingeventonthewholenetwork.(2)thenetworkeffectofdisruptionvaries,dependingonthe“nature”ofthedisruption,thedisruptiontime,networkdesign,andmostimportantlyresourceconnections,andpassengeritineraries.(3)thecostofimplementationiscriticalinchoosingrecoveryplans.(4)scheduleandnetworkrobustnessconsideredinstrategicscheduleplanningalsoinfluenceshowanairlinechooserecoveryplans.2.on-timeperformancemeasurementandstatisticsreportingTheindustrystandardforthedefinitionofan“on-time”departure/arrivalisaflightwhichdeparts/arriveslessthan15minutesafterthescheduleddepartureorarrivaltime(off/onblocktimeatagate)showninthepublishedtimetableofanairlineorequivalentlythetimeshowninthecomputerizedreservationsystems(CRS).Thisstatisticisusuallydenotedby“D15”intheindustry.AusedOTPmeasurementstatisticisthetotaldelaytimeorequivalentlytheaveragedelaytimeperflight.Totaldelaytimecanbemeasureddaily,weekly,monthlyandyearlyforindividualflight,fleettypes,operations(e.g.byregions,airports,anddomesticorinternationaloperations),orforthewholenetwork.AnotherOTPmeasurementstatisticistomeasuretheprobabilityofdeparturedelaysbydelayscauses.BasedontheIATAsystem,airlinecangeneratetheprobabilityofdelaysaccordingtoflights,airports,fleettypesandoperations.AirlinesaroundtheworldarerequiredtoreportOTPdatatotherelevantgoverningagenciesofaviation,dependingonregulationsofindividualcountriesandgoverningagencies.3.inherentdelayofanairlinenetworkThetraditionalprocedureofairlinescheduleplanning:Scheduledesign(demandforecast)FleetassignmentAircraftroutingCrewschedulingScheduleoptimizationobjectiveinvariousschedulingstages:(1)Minimizingoperatingcostsinaircrafttouting;(2)maximizingprofitsinfleetassignment;(3)maximizingmarketpenetrationinscheduledesign;(4)maximizingtheutilizationoffleetandcrewinroutingandcrewscheduling.Schedulebuffertimesareusuallyembeddedwhensolvingaircraftroutingandcrewschedulingproblems.Giventhenatureofstochasticdisruptionsfromdailyflightoperations,airlinesindeedoperate“fixed”schedulesinanenvironmentthatissubjecttostochasticdisruptionsandoperationaluncertainties.Inherentdelays—definitionandmodelingTheinherentOTPlevelofascheduleisdefinedastheimplicitOTP“expectation”ofanairlineonfutureflightoperations,giventhe“willingness”ofanairlinetodesignscheduleflexibilitywithahigherplannedcost,andconsideringpotentialstochasticdisruptionsanddelays.AninherentOTPlevelforschedulereflectthescheduleplanningphilosophyofanairline,e.g.thetradeoffbetweenusingbuffertimetocreateflexibilityandmaximizingfleetutilization.Giventhatanairlinenetworkisatime-varyingnetworkwithstochasticservicetimesofgroundactivitiesandstochasticdisruptionsinthesystem,wecanadoptthenetworksimulation(NS)model.4.scheduleoptimizationandnetworkreliabilitySchedulerobustnessisdefinedasbothaconceptandameasurethatdescribesthe“degree”towhichanairlinescheduleperformsinactualoperation,compared