Analyzing the Effects of Airfield Resources on Airlift Capacity

7/27/2019 Analyzing the Effects of Airfield Resources on Airlift Capacity

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DOCUMENTED BRIEFING

RAND AnalyzingtheEffectsofAirfield ResourcesonAirliftCapacityJamesP .Stucker,LauraMelodyWilliams

National Defense Research Institute

OTICQUAUTT INSPECTED3


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TheresearchdescribedinthisreportwassponsoredbytheOfficeoftheSecretaryofDefenseOSD).heresearchwasconductedinRAND'sNationalDefenseResearchInstitute,afederallyfundedresearchanddevelopmentcentersupported bytheOSD,theJointStaff,heunifiedcommands,andhedefenseagenciesunderContractDASW01-95-C-0059.

ISBN:-8330-2637-2

TheRANDdocumentedbriefingseriessamechanismorimely,easy-to-readreportingofresearchhathasbeenbriefedoheclientandpossiblyootheraudiences.lthoughdocumentedbriefingshavebeenformallyreviewed,heyarenotexpectedtobecomprehensiveordefinitive.nmany cases,theyrepresentinterimwork.

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Published1 9 9 9 byRAND1700MainStreet,P.O.Box 2138,SantaMonica,CA 90407-2138

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ToorderRANDdocumentsortoobtainadditionalinformation,contactDistributionServices:elephone:310)451-7002;Fax:310)451-6915;Internet:[email protected]


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DOCUMENTED BRIEFING

R A N D AnalyzingtheEffectsofAirfield ResourcesonAirliftCapacityJamesP .Stucker ,LauraMelodyWill iams Prepared forth e Office of th eSecretaryofState

D&-Z3O-0SJ)Nat iona l De f enseResea rch Insti tute

PrecedingPagefiank

Approved forpublicrelease;distributionunlimited


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PREFACE

Thisresearchinvestigatedhowdifferinglevelsanddistributionsof airfieldresourcescanaffectthequantityofairliftdeliveries.T heresearchwasconductedfortheForceProjectionDirectorateintheOfficeoftheSecretaryofDefensewithintheForcesandResources PolicyCenterofRAND'sNationalDefenseResearchInstitute,afederallyfundedresearchanddevelopmentcentersponsoredbytheOfficeoftheSecretaryofDefense,theJointStaff,theunifiedcommands,andthedefenseagencies.TheRANDanalystspresentedthisbriefingtotheclientandto representativesfromtheJointStaff,theU.S.TransportationCommand,theAirMobilityCommand,theAirForceStudiesandAnalysisAgency,andotherorganizationsatScottAirForceBase,IllinoisonJuly9 ,1997 .Thisreportshouldbeof interesttodeploymentplannersandtoairmobilityresourceprogrammersandmanagers.

in


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SUMMARY

Airliftcapacitythenumberof passengersandthenumberoftonsof cargothatcanbedeliveredtoaspecificlocationinaspecificperiodof timedependsonthecharacteristicsof(a)thecargoestobedelivered,(b)theairfieldsandtherouteslinkingthecargooriginationswiththecargodestinations,(c)thegroundresourcesattheairfieldssupportingtheairassets,and(d )theairassetsi.e.,theaircraftandtheaircrewsflyingthoseroutes.T he majormobilitystudiesperformedbyandfortheOfficeoftheSecretaryofDefense(OSD)inthe1980sfocusedonthecargoes,theroutes,andtheairassets.nthe1990sthefocuswasexpandedto includeatleastlimitedconsiderationoftheenroute,off-load,andrecoveryairfields. T heair-mobilitymodelofchoicehasbecomeMASS(MobilityAnalysisSupportSystem),alarge-scalesimulationcreatedandoperatedbytheAirForce'sAirMobilityCommand(AMC).Groundresourcesarenotmodeledbutareinputasconstraintstotheairliftmodel.MorerecentlyaseriesofdevelopmentshasledtothecreationofN R M O(theNavalPostgraduateSchool/RANDMobilityOptimization),alarge-scalelinear-programmingmodelofmilitaryairlift,andACEAirfieldCapacityEstimator),arelativelyhigh-resolutionmodelofairfieldresourcesandoperations. ThisstudydemonstratesthecombineduseoftheACEandNR M Omodelsto improveandfacilitatetheanalysisof theeffectsofairfieldresourceson airliftperformance.Whenourstudywasinitiated,AM Canalystswerebriefingthefindingsof theirstudyoftheenrouteairfieldsneededtosuccessfullyexecute theMRC-Eastdeployment. OursponsoraskedthatweusetheAM CscenariotodemonstratehowourmodelsandmethodscouldcomplementAMC'smodelsandanalysesandhowourestimatesmightexpandorvalidatetheirs.Ouranalysesaccomplishedbothobjectives. W evalidatedAMC'sfindingsthatforthe1996scenariothecurrentEuropeanenrouteinfrastructurewouldsignificantlyconstraindeliveriesofmilitarycargoesduringamajordeploymenttoSouthwestAsia. BothweandAM Cestimatedthatcurrentenrouteresourceshortageswouldreduce


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cargodeliveriesbyroughly20percentfromwhattheycouldbeifthoseshortagesdidnotexist.Moreover,weexpandedAMC'sfindings(a)bydemonstratingthesensitivityofdeliveriestoassumptionsconcerningaircraftgroundtimesattheon-load,enroute,andoff-loadairfieldsand(b)bydemonstratinghowabetterdistributionofexistingenrouteresourcescouldsignificantlyincreasetheamountofcargodeliveredduringthefirst30daysof theconflict.In apreviousstudyforOSDandtheAirStaff,wedemonstratedthatmanyofthestandardgroundtimesusedinairliftstudieswerenotlongenoughtoallownecessaryinspectionandservicingofairliftaircraft.1In thepresentstudy,wehaveestimatedspecificgroundtimesforon-load,enroute,andoff-loadstopoversbyeachtypeof airliftaircraftandthencomparedestimatesofairliftdeliveriesbasedonthosetimesas inputswithestimatesofdeliveriesbasedonthemostrecentAirForce-standardgroundtimes.W efoundthatuseof thestandardtimesoverestimateddeliveriesby12to13percent.Airliftsimulationmodelsuseprespecified"rules"oallocatecargoestoaircraftandaircrafttoroutes. Similarly,thegroundresourcesavailableateachairfieldmustbespecifiedbeforeeachrun. T he modelsthenestimatetheflowsanddeliveriesresultingfromtheuseof thoseresourcesandtheapplicationofthoserules. Airliftoptimizationmodelsontheotherhand,cansearchforthebestallocationsofcargoestoaircraftandaircrafttoroutes.he ycanalso,as wehavedemonstrated,searchforthebestallocationof groundresourcesto enrouteairfields. T heresultinganalysescanbequiteusefulto decisionmakerslookingforwaystoexpandairliftcapacitywhenresourcesarelimited.Forsuchascenario,weestimatethatnegotiatingwithourEuropeanalliestoredistributetherampspaceandfuelcurrentlyavailabletoU.S.airliftoperations,withoutincreasingthetotalofeither,couldincreasedeliveriesoverthefirst30daysofthe1996scenarioby12to13percent.Forotherscenariosandotherbaselines,theestimateswilldiffer,buttherelativestrengthsof theanalysesandfindingsshouldremainthesame.ThisstudydemonstratesthatACEandN R M OcancomplementandexpandthestrategicmobilityanalysesneededbyOSDandothers.Together,theseanalytictoolsdetectcapabilitiesandprovideinsightsX J.P .Stucker,R.Berg,etal.,Understanding AirfieldCapacityforAirliftOperations,SantaMonica,Calif.: RAND,MR-700-AF/OSD,1998.

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thatare notavailablefromothermodels.heauthorsrecommendthatACEandNR M Obeadoptedforusebytheair-mobilitycommunity.

Vll


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CONTENT S

Preface iiSummaryAcknowledgments iGlossary iiiINTRODUCTIONRECENTAIRLIFTSTUDIESRevisedIntertheaterMobilityStudyMobilityRequirementsStudy

MobilityRequirementsStudyBottom-UpReviewUpdate 0En Route Structures 2MajorRegionalConflictinSouthwestAsia(MRC-East)1996Scenario 3T HERANDSTUDY 5ApproachandProcedures 6Findings 8T he1996Baseline 9 Effectsof LongerGroundTimes 3EffectsofOptimizing 2AllocatingCargoestoAircraft 5AllocatingAircrafttoRoutes 9 AllocatingRampandFueltoAirfields1CONCLUDINGREMARKS 7References 1

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ACKNOWLEDGMENTS

Ourprojectmonitor,Lt.Col.NormanA.WeinbergoftheForceProjectionDirectorateoftheOSDProgramAnalysisandEvaluationunit,facilitatedourresearchanddataacquisitionactivitiesthroughoutthestudyandorganizedthemeetingsatwhichwepresentedthisbriefing.DaveMerrill,senioranalystattheAirMobilityCommand(AMC),coordinatedandfacilitatedthetransferofdatafromAM CtoRAND andwasinstrumentalin ourunderstandingofAMC'sanalysismethodsandtechniques.RichardRosenthalof theNavalPostgraduateSchool,DavidMortonof theUniversityofTexasatAustin,andStevenBakeroftheU.S.AirForceAcademyprovidedproductiveconsultingandntellectualsupport.AtRAND,SusanHosekguidedthestudy. Sh eandCraigMoore oversawanearlier,lead-instudy,andbothprovidedcontinuingcounselandsupport. PaulDavisandRichardHillestadcritiquedanearlierversionof thisbriefingandprovidedcommentsandsuggestionsonthisreport.CarolZarembaprocessedthefinaldraft. BettyArnoskillfullyeditedandguidedthedocumentthroughfinalproduction.

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GLOSSARYACEAF/XOFMAFMAFSAAALDAMCAPODAPOEBURUCdayCINCCOEACONUSCRAFDoDJ S JS/J8MACMASSMIDASMOGMOMMRCMRC-EastMRC-WestMRSnbNPSNRMOOSDPA&EPODRDDRIMSTPFDL

AirfieldCapacityEstimatorMobilityDivisionoftheDirectorateofForces,Headquarters,U.S.AirForceAirliftFlowModelAirForceStudiesandAnalysisAgencyAvailable-to-loaddateAirMobilityCommandAerialPortofDebarkationAerialPortofEmbarkationBottom-UpReviewUpdateTheunnameddayonwhichadeploymentoperationbeginsoristobeginCommanderinChiefCostandOperationalEffectivenessAnalysisContinental(contiguous)UnitedStatesCivilReserveAirFleetDepartmentofDefenseJointStaffForceStructure,ResourcesandAssessmentDirectorate

oftheJointStaff(Old)MilitaryAirliftCommand,nowAMCMobilityAnalysisSupportSystemModelforIntertheaterDeploymentbyAirandSeaMaximum(aircraft)onGroundMobilityOptimizationModelMajorRegionalConflictMajorRegionalConflictinSouthwestAsiaMajorRegionalConflictinSoutheastAsiaMobilityRequirementsStudyNarrowbody(aircraft)NavalPostgraduateSchoolNPS/RANDMobilityOptimizationOfficeoftheSecretaryofDefenseProgramAnalysisandEvaluationPortofdebarkationRequireddeliverydateRevisedIntertheaterMobilityStudyTime-PhasedForceDeploymentListing

xin


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UTCnitTypeCodeUTEtilization(rate)wbidebody(aircraft)

xiv


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ProjectOverview NDRIi

Challenge: Allocatescarceresourceswisely inorderto improveairliftthroughputProjectpurpose:Adaptandrefinemodelsandmethodsto providebetterinformation todecisionmakers Demonstrate valueofnew analytic perspectives Objectiveofthisbriefing:Demonstra te useofA C Ean dNRM O in estimating thecapaci t ies o fairliftresources

J^^M^^^^^^^^^^^wWWW^^^^^^^^^^M*wwa8^8aiaw^a^^^^^^^^^ iS RAND S U M M M s

INTRODUCTIONThisresearchprojectwasdesignedtoexpandOSD's(OfficeoftheSecretaryofDefense's)capabilityforconducting,understanding,andusingmobilityanalyses.Morespecifically,theresearchobjectivesweretofindwaystousetheACEandN R M Omodelstogethertolinkairfieldresourceswithairfieldcapacity. ACEisourAirfieldCapacityEstimator,amodeldevelopedoverthepastseveralyearsatRANDforOSDandtheU.S.AirForce. N R M OistheNavalPostgraduateSchool/RANDMobilityOptimization,anairliftmodeldevelopedoverthepastyearatRANDandtheNavalPostgraduateSchool.T heobjectiveofthisbriefingistodemonstratehowthetwomodelscanbeusedtogethertoestimatethecapacityof aspecificairliftsystem the1996airliftfleet,routes,andresourcesinaspecificscenario MRC-East(majorregionalconflictinSouthwestAsia).


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Conceptua lOverview (1 )[ Inputs

Missionvariables C argoesRoutes & policies Leg & gro undt imes I" = J Airli ftresourcesAircraf tAircrews Airfield capabil it iesI" = J

-Vf \AirliftMod e l

^ J

-> AirliftCapacity

RAND

First,wewillgiveaquickoverviewofourprocedures.We'regoingto beusinganairliftmodeltoestimateairliftcapacitythenumberof passengersandthenumberof tonsofcargothatcanbedeliveredtoaspecificlocationinaspecificperiodoftime.Thatcapacitydependsbothonthecharacteristicsofthemissionswewanttheairlifttoperformandontheresourceswehaveavailableto performandservicethosemissions.


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ConceptualOverview (2 )NDRli

DataorModel (s) Ground Times Dataor Model (s)

I nputs Missionvariables Cargoes Routes &policiesLeg &ground timesetc..AirliftresourcesAircraftAircrews Airfieldcapabilities*=r \AirliftMode l - AirliftCapaci ty > . )

RAND

Airliftcapacityalsodependsonthetimestheminutesandhoursthatweexpecttheairliftaircraftwillneedtobeonthegroundattheon-loadpoints,attheenroutestops,attheoff-loadpoints,andperhapsatrecoveryairfields;anditdependsonthenumberandthequalityoftheresourcesavailableateachofthoseairfields.W efocusonthesetimesandresourcecapacitiesinthisbriefing.In thepast,estimatesof aircraftgroundtimeandairfieldcapacityusedasinputsinairliftstudieswereproducedatleastsomewhatindependently,perhapsevenbydifferentorganizations. W ewillsummarizeseveralof themoreimportantandrecentairliftstudies. But first,we'llintroduceourprocedures.


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Conceptua lOverview (3 )I nputs Inputs

Mission variables Aircraf ttypeAircraf tquant ityServices needed etc...Ground resources Parking spaceServicing crews Fueletc...

Aircraf tGrou nd TimesAirfieldMod e l

Missionvariables C argoesRoutes &pol iciesLe g&gro undt imes

irfieldCapacit ies Airli ftresourcesAircraf tAircrews Airfield capabil it iesetc...

->

-*

f > AirliftMod e l)-> AirliftCapacity

RAND

Ourproceduresnvolveusinganairfieldmodeltoproducemore-detailedandmore-consistentestimatesofaircraftgroundtimesandairfieldcapacities.


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Conceptua lOverview (4)I nputs

Missionvariables Aircraf ttype Aircraf tquantityServices neededGround resources Parking spaceServicingcrews Fueletc...

AirfieldModel

i! II AircraftGrouna Times iiAirfield Capacit ies

I nputs MissionvariablesCa rgo esRoutes&pol iciesLe g &ground t imesI" = Airlift resources Aircraf tAircrewsAirfieldcapabil i t iesetc...

AirliftCapacity

ACE NRMO

RAND

Inparticular,ourprocedureswillinvolveusingACE andusingN R M O .


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ThisBriefing Objectives:

Demonstrateuseof AC EandNRMOinestimating th ecapacities ofairliftresourcesPlan:

I. In t roduct ion =>I- Recent airliftstudies -RIMS,MRS,MRS-BURU -AMC'sStudyof EuropeanAirfields

i n . TheR A N D study -Approach-Findings

IV . C o n c l u d i n gremarks RAND ^ n

RECENTAIRLIFTSTUDIESW ewillverybrieflysummarizethemajormobilitystudiesof thepastdecade: theRevisedIntertheaterMobilityStudy(RIMS)thatwasconductedin thelate1980sanddocumentedinaseriesofreportsissuedin1989;theMobilityRequirementsStudy(MRS)thatwasdoneafe wyearslaterandpublishedin1992;andtheMRS-Bottom-UpReview Update(MRSBURU)thatwasdoneafe wyearsafterthatandpublishedin1996. Althoughthesereportsareclassifiedbecauseofsomeofthedetailedinformationtheycontain,ourpurposeswillbeservedbyreferringtothemoregeneralproceduresandfindingsthatarenotclassified.Then,wewillsummarizetheAM Cstudy,conductedduring1996,oftheMRC-East(MRC-E)enrouteairfields. ThiswascalledtheEuropeanAirMobilityInfrastructureAnalysis. Anditisthestudy,ormorecorrectlythescenario,onwhichOSDaskedustodemonstrateourmodelsandourtechniques.Afterthat,wewilldescribetheRANDstudy.


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S u mma r yofStudies(1 )NDRIl

Title RIMSYear: 1989Model: MIDASOwner: OSD/JSTypesofaircraft:#groundt imes: 5 2 Typesofairfields: Resources: O ff R a m p Findingconcerning enrouteairfields: n/a

RAND

RevisedIntertheaterMobilityStudyRIMSwasconductedinthecold-warera. ItsscenarioinvolvedtheUSSRinvadingIran,andthenaconsolidatedattackbytheWarsaw-PactnationsagainstWesternEurope.AirliftcapacityinthisstudywasestimatedusingMIDAS,the(thenandnow)majormobilitymodelusedbyOSDandtheJointStaff(JS).MIDASstandsforModelforIntertheaterDeploymentbyAirandSea.Ithasbeenupdatedseveraltimes;atthattimeitmodeled,ingreatdetail,sealiftships,theircargoes,andtheirroutingsandprogressalongthoseroutingsbuthadonlyanequationortwodealingwithairlift. Thoseequationsrelatedseveralexogenousvariablesthenumberandtypesofaircraft,theircycletimes,andtheirallowable-useratestoairliftcapacity.1RIMSwascoordinatedbytheJointStaffandwassupportedbyallthemilitaryservices,includingtheAirForce,which(throughAM C(thenMAC,MilitaryAirliftCommand))providedtheestimatesofaircraftgroundtimes.hegroundtimesattheoff-loadingsiteswere2hours1J.Schnk,M .Mattock,G .Sumner,I.Greenberg,J.Rothenberg,andJ.P .Stucker,AReviewof StrategicMobilityModelsandAnalysis,SantaMonica,Calif.: RAND,R-3926-JS,1991.


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and20minutesfo rrelativelynarrow-body(nb)aircraftliketheC-141 and3hoursand20minutesforwide-body(wb)aircraftliketheC-5.On-loading,enroute,andrecoveryairfieldswereassumedtohavecapacitysufficientnottoconstraintheairliftflow.T heonlyairfieldresourceinvestigatedwasramp,orparkingspace:thespace(andtime)availableforparkingandservicingaircraftattheairfield.2Airfieldcapacitywasexpressedassortiesperdaybyaircrafttype. T heanalysisrevealedsomebottlenecksattheoff-loadingsitesinvestigated.2In air-mobilitystudies,rampspaceisoftenreferredtoasM O G ,themaximumnumberofaircraftthatcan beparked(and/orserviced)on thegroundaton etime.


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S um m aryofStudies(2 )Title RIMS MRS

Year: 1989 1992 Model: MIDAS MO M Owner: OSD/JS JS/J8Typesofaircraft:# ground t imes: 5 2 88Typesofairfields:Resources: O ff R a mp En/OffR a m p Finding concerning enrouteairfields: n /a O K

RAND

MobilityRequirementsStudyTheMobilityRequirementsStudy,conductedafe wyearslater,movedawayfromtheEuropeanscenarioandlookedatthethennewMRC-EastandMRC-West(majorregionalconflictinSoutheastAsia)scenarios.AirliftcapacityinthisstudywasestimatedusinganoptimizationmodelnewlydevelopedbyJS/J8ForceStructure,Resources,andAssessmentDirectorateof theJointStaff),calledM O M ,ortheMobilityOptimizationModel . ProfessorRichardRosenthaloftheNavalPostgraduateSchoolwaspartofthatdevelopmentteam,andmorerecentlyhewasinstrumentalintheNR M Odevelopment,soM OM is likethegrandfather(or,moreappropriately,thegrandmother)of NR M O .AircraftgroundtimesandairfieldcapacitiesintermsofsortiesperdaywereprovidedbytheAirForce. Bothenrouteandoff-load airfieldswerestudied;on-loadandrecoveryairfieldswerenot.Differentgroundtimeswerespecifiedfo reighttypesofaircraft;airfieldcapacitystilldependedonlyonrampspace.T hestudyidentifiedsomeAP O D(AerialPortofDebarkation)shortfallsbutconcludedthattheenrouteairfieldscouldhandlethedeploymenttrafficadequately.


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S um m ary ofStudies(3 )Title RIMS MRS MRSB um

Year: 1989 1992 1994 Model: MIDAS MOM MASSOwner: OSD/JS JS/J8 AF/AMC Typesofaircraft:#groundt imes: 52 88 832 Typesofairfields: Resources: O ff R a mp En/OffR a m p En/Off/RecR a m p ,FuelFinding concerning enroute airf ields: n/a O K O K

RAND

MobilityRequirementsStudyBottom-UpReviewUpdateM RSBURUwasrun bytheJointStaff,withparticipationbyOSD,thecombatantcommands,andthemilitaryservices.T heAirForcehadmorevisibilityhere. T heairliftestimateswereprovidedbyAMC'scomputerizedanalysissystem,MASSMobility AnalysisSupportSystem),anditsprimarysimulationmodel,AFM (AirliftFlowModel).Groundtimesweredifferentiatedbyaircrafttypeandbystopovertype.hatis ,on-loadstopswerethelongest;enroutestopswereonlyforrefueling,aquickinspection,andminorservicing;andoff-load stopsusuallydidnotinvolvethefueling,servicing,orcrewchangesthatwerehandledattherecoveryairfields.Thisstudyinvestigatedairfieldcapacityforenroute,off-load,andrecoveryfields.3tconsideredfuelaswellasramp. AirForceplannersspecifiedthedailyquantityorquotaof fuelthatwasassumedtobeavailable;theneachaircraftusedsomeofthatfueluntilitwasallgone.3Thisstudy,asdidthosebeforeit,assumedthattheon-loadairfields,mostlywithinthecontinentalUnitedStates,wouldal lhavemorethansufficientcapacitytosupporttheairlift.

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Despitetheincreasedfocusonairfields,however,thestudyfoundtheairfieldresources,includingthoseattheenrouteairfields,tobe sufficient.

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AMC'sStudyofMRC-EEnRouteAirfields (1996)NDRIl

MRC-EAirliftestimatedusingMASSAircraftgroundtimes

141,C5,C-17,KC-10,747P ,747C,NBCOn-load,enroute,off-load

Airfieldcapacityfor enrouteairfieldsAirfieldcapacity expressedas sortiesperdayby aircraft type-BasedonMOG(nb,wb)and fuelocation,forcelimitationsSomeenrouteshortfalls RANDiiiiii

E nRouteStructuresMostrecently,AMCanalystshavelookedatboththeEuropeanenroutestructureandhePacificenroutestructure.Asourstudywasbeingstructured,theywerebriefingtheirfindingsfortheEuropeanscenariohroughouttheAirForceandOSD.AMCanalystsusedMASS,theirairliftsystemsimulation. Theyagainusedaircraftgroundtimesbasedonaircrafttypeandstopovertype,andtheylookedatbothrampandfuelconstraintsateachoftheenrouteairfields.Theyalsoconsidered,butinqualitativeways,studyfactorsastheweatheratthedifferentairfieldsandthepotentialpoliticalconstraintsthatmightaffectthedifferentnationsandregions.TheyranMASStoestablishrequirementsforinfrastructureneededatenrouteairfields. TheyusedstandardAMCoperatingrulesforallocatingaircraftandcargoestoroutesandairfields. Theyderivedaverageenrouteneedsoverdays0-29. Theyassessedairfieldcapabilityatpackagesofenrouteairfields. Andtheyestimatedairliftthroughputassociatedwitheachofthosepackages.Asaresultofthatanalysis,theyestimatedaneedforadditionalairfieldresources.

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AM C' sFindings 1,000 tons of f re igh tp er da y

2001 1996 ,,nj/Sixairfields:Fairford MildenhallMoron RotaR a mst e i n

RheinMain RAND IBMajorRegionalConflictinSouthwestAsia(MRC-East)1996ScenarioForMRC-East ,ourscenarioof interest,AM Canalystsmodeledthemovementofcargoesunderthreescenarios:

he1996aircraftfleetandthe1996airfieldresources;he2001fleetandresources;andhe2006fleetandresources.ConsideringbothmilitaryandCRAF(CivilReserveAirFleet)capabilities,theyestimatedthatcurrentairfieldresourceswould

significantlyconstrainthedeliveryofMRC-Ecargoes: T he1996airliftfleetwouldbe capableofdeliveringanaverageof 4.3thousandtonsofcargoperdayfo rthefirst30daysof theconflict, butlimitationsattheenrouteairfieldswouldconstrainthosedeliveriestoabout3.5 thousandtonsperday.AM Canalystsestimatedthatthesituationwouldbeimprovedsubstantiallyby2001:heacquisitionof C-17swouldmorethanoffsettheretirementofC-141s,andtheimprovementsinrampandfuelingattheenrouteairfieldscouldincreasethroughputtoabout4.2thousandtonsperday. Furtheradditionsandimprovementstotheenrouteinfrastructureby2006wouldincreasethroughputtonearly5thousand

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tonsperday,atwhichpointthebindingconstraintwouldbetheaircraft,nottheenrouteairfields.

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ThisBriefingObjectives:Demonstrateuseof ACE andNRMOinestimatingthecapacities of airliftresourcesPlan :

I . Introduction II. Recentairliftstudies

!=!> III. TheRAND study-Approach-FindingsIV . Concluding remarks

RAND

THERANDSTUDY Asmentionedbefore,thisstudywasbeinginitiatedwhenAMC'sbriefingontheEuropeanenrouteinfrastructurewasbeingworkedthroughtheDepartmentofDefense(DoD). Consequently,oursponsorsuggestedthatweusethatsamescenarioandmuchof thesamedatato demonstratehowournewlydevelopedmodelsandmethodscouldcomplementAMC'smodelsandanalyses,aswellashowourestimatesmightexpandorvalidateAMC's.

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O urProcedures MRC-Escenario

M o v e m e n trequirements Orig ins&dest inat ions

AMC'sparameters n route airfieldconstra ints -B u tnoonload oroff load constra ints Aircraftf leets&availabilit ies -Military&C R A F -C R A Fenroutes i ndependen t

RAND /NPSmodelsaysC +0th roughC + 2 9 ACE :ircraftground t imesR M O :ptimized al locat ions RANDlist

ApproachandProceduresW eusedtheairlift,aircraft,andairfieldparametersprovidedbyAMC,thesameparametersusedin itsMRC-Estudy.Butweusednewmodels:nsteadofusingtheAirForce'sstandardestimatesforthegroundtimesofairliftaircraftatthevarioustypesofairfields,weusedourairfieldoperationsmodel,ACE,togeneratenewerestimates. Thenweusedthoseestimatesinouroptimizationmodel,NR M O .T henextseveralchartsbrieflydescribeACEandN R M O .

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Genea logyofth eModels NDRI I

( MOM )1M0^< JS/J8 "Enhancing the EffectivenessofMobility Forces" I Airf ieldCapab i l i t y i i Tanker St u d y IIC-17Tact icalUtil ity |

( Ac e ( C O N O P )

CHRUPUT)"*"RANDTHROUGHPUrII(PABNDRI) '

\ M o d e lDevelopment NPS/RAND (PAF)jt'

this studyRAND(NDRI)

RAND Note:A F isProjectAI RF OR C E ,RAND' sfederal ly fundedd e ve l o pm e ntcenter forth eU. S .AirForce.

Thisslideshowsthebackgroundof themodelswe'vedevelopedoverthepastseveralyears.OntheNR M Osideof thegraph:

M O M ,theMobilityOptimizationModel,developedbyJS/J8andusedintheMobilityRequirementsStudy,representedtimeadequatelybutallowedlittlegeographicaldetail.4H R UP UT ,developedbytheAirForceStudiesandAnalysisAgency(AFSAA),was,on theotherhand,asteady-statemodelallowingextensiverepresentationof thegeographicalnetwork.5

HR O U G HP U TIIwasdevelopedbytheNavalPostgraduateSchool(NPS)undercontractwithAFSAA. Itcombinedthebestof 4V .F.Wing,R.E.Rice,R.W.Sherwood,andR.E.Rosenthal,Determininghe OptimalMobilityMix,Washington,D.C.:JS/J8,ForceDesignDivision,October1, 1991.5K.A.Yost,TheTHRUPUTStrategicAirliftFlowOptimizationModel,AirForceStudiesandAnalysesAgency,June30,1994.

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T H R UP UTandM O M ,allowingextensiveelaborationofbothtimeandgeographicaldetail.6

CONOPisaRANDmodelthatextendedandappliedthoseprinciples. Ithasbeenusedinpolicyanalysesaddressing(a)theoptimumdeploymentandemploymentoftankers,exploitingtheircargo-carryingaswellastheirrefuelingcapabilities,and(b)theutilityoftheC-17sintactical,strategic,andcombinedroles.7

NR M Oisatruemerger/offspringofthislineage.Althoughitwasspecifiedandprogrammedfromscratch,itcontainsmanyofthecontextual,analytic,andprogrammingtechniquesdevelopedinassociationwiththeearliermodelsdescribed.ACE,ontheotherhand,wascreatedinresponsetoaspecific need.n thespringof1994,OSDwascoordinatingtheAirliftRequirementsStudy,inwhichMASSwastobeusedtoanalyzealternativefleetsof passengerandcargoaircraft. Butthethen-recentCostandOperationalEffectivenessAnalysis(COEA)fo rtheC-17hadseriouslyquestionedcertainMASSinputs: (a)theutilizationratesforaircraftandcrewsand(b)capacityestimatesforairfields. In response,AM Cundertookto improvetheestimatesoftheutilizationrates,andOSDandtheAirStafffundedRANDtodevelopmethodsforestimatingairfieldcapacity.ThatinitialdevelopmentofACEwassponsoredbytheProjectionForcesDivision,OSDProgramAnalysisandEvaluation(PA&E),andtheMobilityForcesDivision,HeadquartersAirForce. SubsequentdevelopmentandthisapplicationhavebeenfundedbyProjectionForces.86D.P .Morton,R.E.Rosenthal,andT.W .Lim,"OptimizationModelingforAirliftMobility,"OperationsResearch ,ol. ,No.3,1 9 9 5 . (AlsoavailableasNPS-OR-95-007,Monterey,Calif.: NavalPostgraduateSchool.)7P.KillingsworthandL.Melody,ShouldC-17sBeUsedtoCarryIn-TheaterCargoDuringMajorDeployments? SantaMonica,Calif.: RAND,DB-171-AF-OSD,1997 ; andunpublishedRANDreasearchbyP.KillingsworthandL.Melodyon"Tankers: AirMobilityRolesforthe1990s."8J.P.StuckerandR.Berg,withA.Gerner,A.Giarla,W .Spencer,L.Arghavan,andR.Gates,UnderstandingAirfieldCapaci tyforAirliftOperat ions,SantaMonica,Calif.:RAND,MR-700-AF/OSD, 998.

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Airfield Capacity Est imator8 , 000f eet

R a m p C

1,000 feet

3,500f eet

5b u sesG P U sR L1 2 H S V s20WBELSmain te nanc e crewsR9 fuel trucks20 40k- load ersoreach type of aircraftR11 f u e l trucksFu el inge q u i p m e n t&p e r s o n n e lsufficientto work5aircraft ta time,24 hou rspe r d ay .Load ing e q u ipme nt& personnel sufficient to work5 aircraft ta time,24 hou rsperd ay .Servic ing equipment & personnel sufficient to work 5aircraf tt a time,24 hou rsperd ay .

RAND Note:B EL =wid e bo d yelevatorloader ,GP U =gr o und -po we runi t ,an dH SV =hydrant-servicevehic le .

TorunACE,theuserfirstdescribestheairfield. Hecanspecifyupto sixseparateanddistinctparkingareas,orramps;eachwithaspecific setupfo rhydrantfueling,andallsharingtanker-trucksandcrewsfor truck-basedfueling. Eachrampislocatedaspecifieddistancefromthecargo-dispensingandstoragearea,thepassengerterminal,andthefuel-dispensingfacilities.ACEestimatesthenumberofaircraftassignedtoparticularmissionsandthusrequiringparticularservicesandservicingthattheairfieldcanserviceinatypicalday.

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A C EGr aph ic a lU se rIn ter face

Excels /VBA

RANDACEisaMicrosoftExcelapplication.heACEpackageconsistsof7Excelworkbooks,containing52worksheetsand16codemodules(the codeisVisualBasicforApplications(VBA));themodelitselfconsistsof4workbookscontaining34worksheetsand13codemodules.9ACErepresentstheparkingandservicing,loadingandunloading,andfuelingoperationsindetail. Italsorepresentsair-trafficcontrol,groundcontrol,andair-crewservicing,butwithlittledetail.ACEcoversmanygroundoperations,tasks,andresources,butwehavenotattemptedtomodelal lof theresourcesandtheiruses.orthemostimportantareasparking,servicing,oading,andfuelingACE containsbothanaggregateresourcethepackages,orUnit-TypeCodes(UTCs),ofskillsandequipmentthattheAirForceregardsas necessarytoperformthosefunctionsandseveralindividualresourcesthatexpertshaveidentifiedasbeingespecially(ormostvisibly)associatedwithairfieldcapacity. Iftheuserhasinformationon thoseindividualresources,thatinformationcanbeinputandthemodelwillcalculatethelimitsof thoseresourcesandtesttose eifanyof themaremoreconstrainingthantheaggregateresource.Ontheotherhand,iftheuserhasnoinformationon someof theindividual9Inearly1 9 9 8 ,softwarefortheACEmodelbecameavailableontheRANDhomepageontheWorldWideWebathttp://www.rand.org/publications/MR/MR700/ACE/.

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resources,orevenoftheaggregateresource,hecansettheirquantitiesto9999andthemodelwillconsiderthemasunlimitedandneverconstraining.

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AC EServicingProfile:uick Turn Standardopera tions:

1 81 IIhru-flight| General BO | Nitroj Oxygen 11Nitrogen [ Open jj Repair | Repair

Mission-related options: BE Fuel IIH [Load]

j Oo-iee|Unloadpax | Loadpa*\ Unloadcargo \ Loadcargo

\ TotalAircraft Ground Time 1

AGTl=BI+MaxMi

'G+DI+BO

RAND

ACErecognizesairfieldresources,operations,andtasks;usingthose,itconstructsservicingtimesforeachresourceandthenthetotaltimethateachaircraftmustspendonthegroundatthatparticularairfield. Thatis,dependingonthetasksandquantityrequirementsforaparticularmission,themodelcomputestheamountandtimerequiredofeachtypeofresource(e.g.,GPU-hours,parking-space-hours,etc.).ACEconsiders1 7groundoperations,morethan40typesofgroundresources,uptosixtasksineachoperationforeachresource;uptosixdistinctareasforparkingandservicingaircraft(eachareamayhaveadistincthydrant-fuelingsystem;allmaybeservicedbycommonfuelingtrucksandteams);anduptoninetypesofaircraft,withuptosixofthoseinterminglingoperationsinatypicalday.10Weshowheretheoperationsassociatedwitha"quickturn,"oneofourground-servicingprofiles. Thetimelinesindicatethesequencingoftheservicingoperations;theyalsoshowtheoperationsthatcanbe10ACEwasdevelopedovertwoyearsofstudyandexperimentation.Weinterviewedscoresofservicepersonnel,technicians,andplannersduringvisitstomorethanadozenairfieldsaroundtheworld,andwemademultiplevisitstotheheadquartersoftheAirMobilityCommandatScottAirForceBase,Illinois. WecollectedmuchofourC-17dataduringitssurgetestingunder"austere"conditionsat Barstow/DaggettAirFieldandFortIrwin,California,inJulyof1996.

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conductedconcurrently(suchasinspections,repairs,off-loadings,andsomeservicingoperations),andthosethatmustbeconductedinisolation(suchasfueltransfer,oxygenservicing,andde-icing).Aquickturnisnormallyassociatedwithservicingatenrouteandoff-loadairfields. Morecomprehensiveservicing,normallyassociatedwithhome-fieldorCONUS(Continental(contiguous)UnitedStates)stopovers,iscalled"full-service." In additiontoquickturnsandfull-servicestops,themodelalsoenablestheusertocustomizetheground-servicingprofilesforanygroupofaircraft,allowingconcurrencyof fueltransferandservicing,"engine-runningoff-loads,"andmanyothersequences.Ofthe17operationswemodel,weuseaveragetimes(byaircrafttype)foreight,becausewebelievethattheirdurationandresourcedemandsvarylittleformissionsorairfields.he otherninearetreatedinon eof twoways.orfiveofthemfueling(transfer),passengerandcargoloading,andpassengerandcargounloadingwecalculatespecifictimesfo reachmissionateachairfieldbyaccumulatingtimesforparticulartaskse.g.,drivingafueltrucktotheaircraft,hookingup,loadingonepalletontoak-loader,ormovingonepalletfromthek-loaderontotheaircraft.hisallowsustoaccountforloadtypesandsizesandforthedistancesthatloadsandfuelsmustbetransported.Furthermore,itallowsustoidentifyandquantifyaircraftdelayswhenresourcesarelimited. Thatis,whenfuelingandloadingareinvolved,aircraftgroundtimedependsonthequantityofairfieldresourcesaswellasonthetypeof aircraft,thetypeofstopover,andtheparticulargroundoperationsspecifiedforthestopover.Timesfortheremainingfouroperationsnitrogenservicing,oxygenservicing,repair,andde-icingdoseemtovarywidely,evenforaircraftofaspecifiedtypeandassignedtoaspecifiedmission.

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BreakRatesandServicing Times NDRII

a x=probabilityofneedingnilrogen service ,=dummyfo rneedingnitrogen service o,=probabilityofneedingoxygenservice h=dummyfo r needingoxygenservice cc 3= probabilityofneedingrepairs 03 =dummyfo rneedingrepairs tt4= probabilityofneeding de-icing . =dummyfor needingde-icing

AGT= Ma x,i,h,)

MinimumGroundTime+DI+BORAND

ACEhandlesthevariabilityofthesefouroperationsineitherof twoways,attheuser'soption.non eoption,theusercanspecifyexpected-valuecalculationstoestimateaverageresource-usetimes,aircraft-groundtimes,andairfieldcapacities. Thisprocessdoesnotyieldthetrue"expectedvalue"ofcapacitybecauseboththeservice-timeequationsandthecapacityequationsarenonlinear,butinallthecaseswehavetested,ityieldsacloseapproximationtothatvalue,anditis quick.Alternatively,theusercanspecifythatACEconductMonte-Carloexperiments,drawingvalues(foreachaircraftineachmission)forthoseoperationaltimesfromempiricallyderiveddistributionsofpasttimes.11herandomdrawsforeachsetofmissionscanbeiterated10,20,oreven1,000times,producingrepresentationsof theoutputdistributionsforusetimes,aircraftgroundtimes,andairfieldcapacity.Thisprocessinsuresthatsomeexceptionallylongandsomeexceptionallyshortrepairtimeswilloccur,atleastoccasionally. Givenvaliddata,thisprocessproduces"better"estimatesthantheexpected-valueapproximation,butittakessubstantiallylonger.nD.A.Goggins,StochasticModelingforAircraftMobility,Master'sThesis,Monterey,Calif.: NavalPostgraduateSchool,1995,AppendixB.

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ACEMission-Specification Screen Expected-ValueComputations

Mission1MissionSpecifications

A: pecifyaircraftcharacteristics Mssionidentifier(userd) X001NumberofaircraftdesiredpBr dayAircrafttypeAircraftconfigurationProfileforgroundoperations

Pressbeforeproceeding: y SetupM1JB:pecifymissioncharacteristics Quantityof fuelrequiredfbs)

Fueltransfermustbeisolated

X005 XOOG 0 0 KC10 74 7 Carao ^ Cargo QuickTurn QuickTurn "

CetupM2Q ( Set upM3 ( SetupM4~) ( SetupMsQ (etupM6~)

Paxto beoff-loaded Paxto beon-loadedPaletstobeoff-loaded Paletstobeon-loadedTypeofnonpailetizedcargo

Percenttobeoff-loaded Percenttobeon-loaded

De-icingrequired(on%of flights)MnimumgroundtimerequiredMintimeetween lockout& lockn

50,000 125.000 300.000 150.000 300.000 300,000 Yes Yes Yes Yes V y.. 0 0 0 0 0 o 0 0 0 0 0 0 6 13 36 IS 26 42 0 0 0 0 0 0 (none) Inonol Ineno) (none) (nono) [nono) ( ) - 1 (n/a) W (n/e) T (n/ (n/a) (n/a) |In/) -I In/a) w ( > In/e) < r (n/a) (n/a) |(one, (none)

(nono)

" ,e., (one, (nono) ^ (none) ^ ,| M Lone,

- 1 - 1 1none)|,e.)

(nonn,- 1 , . , (nona

I(one, (one, (nono) 1

GotoParameterControl[EvaMjf EvalM2 j|f EvalM3 W EvalM4 \~EvalM5 Jf EvalM6 jp j

f Evall-2 j( Eval1 -3 ] I Eval1- 4 j :i].Tocustomizemissiontimes&freqs,

chooseyesherebeforepressingeva

T heACEmission-specificationscreenlookslikethis. Ausercansetupasmanyassixmissiontypesatatime,workingfromrighttoleft.AnACEmissiontype,usuallyjustcalledamission,issomenumberof aircraftofaparticulartypeandconfiguration,eachrequiringthesamegroundservicing.Foreachmission,workingfromtoptobottom,theusermustspecifythefollowing,usingthedrop-downmenus:

umberofaircraftrequiredtoperformthemission;ypeofaircraft(C-141,C-5,C-17,etc.);onfigurationofthoseaircraft(maximumcargo,maximumpassenger,mixed);heground-servicingprofile(quick-turn,ull-service).

Enteringthisinformationgetstheuserthroughtheupperportionof thescreen.henhemustpushthe"setitup"button,whichtellsthemodeltobringinthespecificparametersassociatedwiththataircrafttype,configuration,andservicingprofileandsetsupspecializedmenusforthedrop-downinthelowerportionofthescreen.

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Continuingdownthecolumnassociatedwiththemission,theuserthenselects: thequantityof fueltobeon-loaded;whetherthattransfercanbeconcurrentwithotherservicing;howmanypassengerstooff-loadduringthisstopover;howmanypassengerstoon-load;howmanypalletstooff-load;howmanypalletstoon-load;whattypeofnonpalletizedcargotooff-loadandon-load;thepercentageofthisparticularaircrafttype'scapacityforthetypeof cargotooff-load;thepercentagetoon-load;thepercentageofthetimethatde-icingmayberequired(maybe zero);theminimumgroundtimefo rthisstopover(maybezero);andthe"opentime"betweenaircraftusingaparticularparkingspot.

Makingtheseselectionsfullyspecifiesthemission.Nextcomestheevaluationprocess.Nearthebottomof thescreenareanumberof"eval"buttons. Oneforeachmissiontellsthemodelto evaluatethatparticularmission;andbelowthat,onefo reachof theright-mostfivemissionstellsthemodeltoevaluateallof themissionsfromthefirstthroughtheparticularmissionassociatedwiththebutton.Missionsareevaluated,astheywereprioritized,fromlefttoright.Aircraftassociatedwiththefirstmissionhaveaccesstoalltheresourcesavailableattheairfield. Aircraftassociatedwiththesecondmissionhaveaccesstoal ltheresourcesnotusedbythefirstmission.notherwords,whennon-zeronumbersofaircraftareassociatedwitheachmission,theestimatedcapacitiesare"and"capacities. Thatis,theresourcesavailableattheairfieldcanservicethenumberofaircraftassociatedwiththefirstmissionandthenumberof (thetypeof)aircraftassociatedwiththesecondmission,andsoon ,untiltheairfieldresourcesaredepleted.

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Iftheuserspecifiesthatzeroaircraftshouldbeassociatedwitha(orwitheach)missiontype,thenthemodelestimatesthetotalnumberof aircraftonthat(those)mission(s)thatcouldbeservicedwiththeavailableresources. Iftheuserspecifieszeroaircraftforeverymission,thenthemodelestimates"or"capacities:heresourcesatthisairfieldcouldsupportX Iaircraftassignedtomission1,orX2aircraftassignedtomission2,etc.* Whenauserspecifiessomemissionswithzeroaircraftandotherswithsomeaircraft,ACE estimatescombinationsof"ands"and"ors."*Notethatausercan runthemodelfo rmission1,thenconsidertheresultingoutputandse tupthesecondmissionandrunit,etc.,solongasheunderstandsthateachmissionhasaccessonlytotheresourcesavailableattheconclusionofthelastrun(exceptfo rthefirstmission,whichalwayshasaccesstoalloftheairfield'sresources).Thatis,iftheuserevaluatesfourmissionsandthenattemptstoevaluatesomeversionofmission2again,themodelwillprovideestimatesfo rthatmission2,butthoseestimateswillbe basedonlyon theresourcesremainingaftertheevaluationsofthepreviousfourmissions. Only(re)evaluatingmission1resetstheairfieldresourcesto theiroriginallevels.

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AC E"Output"ScreenMissionan dCapacityEst imates

Expected-Value C omp iMissionspecifications

MssionD Aircraft onMssionAircraft typeAircraft configuration ServicingprofileFuelingmustbeFuelneededlbs) Passengersoff,onPaletsoff,onNonpaletized cargoNPCpercentoff,on

MissionoutputsCapacityusedaircraft perday)Averagemissiontimeshours,minutBs

Loading&unloading FueltransferAircraftgroundtime

Margina (FPA)timeshours,minutes)Loading&unloading FueltransferAircraftgroundtime

Capacitiesremaining:Parkingtota)Aircraft servicing

j tations Medium SizedAirfield Executiontimeminutes)= 3.22Mission Mission2 Mission3 Mission4 Mission5 Mission6

X001 0

X0020

X0030

X0040

X0050

X00G0

C130Cargo C141 Cargo

C5Cargo C17Cargo

KC10Cargo747Cargo

Quick TurnSequentia

QuickTurnSequentia

QuickTurnSequentia

QuickTurnSequentia

Quick TurnSequentia

QuickTurnSequentia

60,0000 0

125,0000 0

300,0000 0

150,0000 0 300,0000 0300,000

0 0 6 0

(none)13 0

(none)36 0

(none)18 0

(none)26 0

(none)42 0

(none)(n/a) (n/a)

0 0 0"0 0"0 0"0 23"0 46"1 41

(n/a) (n/a)

00 0"0 0"0 0"0 31r 4"2 50"

(n/a) (n/a)

0 0 0"0 00 0"1 14"r 57"4 24"

(n/a) (n/a)

0 0 0"0 0"0 0"0 36"1 12 2' 62"

(n/a) (n/a)

0 o* o-0 0"0 0"0 58"1' 57"4' 46"

(n/a) n/a)

0 0 0"0 0"0 0"2 17"1 57"4' 33"

32366

17637

2723

18236

2521

2622

LoadingAircrewsupportAir-traffic controlFuelingGroundcontrol

72250

72250

27250

54250

30250 250

24042

24042

24042

24042

2404224042

60 80 80 80 eo 80ReturntoMissionControl

ThisgraphicshowstheACE"output"screen. Again,sixmissionscan be shownfromlefttoright.heupperportionofthescreenrepeatsthemajorspecificationsof themissions. Itshowsthenumberof aircraftrequestedforeachmission.T hecenterportionshowsthetimeestimatesforservicing,loading,andfueling,aswellasthetotalrequiredgroundtimefortheaircraft.tshowsthenumberofrequestedaircraftthatthemodelestimatescouldbeservicedusingtheairfield'savailableresources.T helowerportionshowstheresourcecapacitiesremaining,byservicefunction,aftertheaircraftassignedtoeachmissionareserviced. Eachofthesecapacitiesisexpressedintermsoftheparticularmissionspecified. (Amoregeneralcapacitycannotbeestimatedatthattimebecause,atthecompletionofeachmissionevaluation,themodelmuststandreadytoevaluateanyspecificationofthenextmission.)Thus,whentheuserasksforzeroaircraftforamission,thelowerportionofthescreenshowsthetotalcapacityoftheairfieldfor servicingaircraftassignedtothatmission. T hesmallestcapacityreportedherewill,ofcourse,bethebindingcapacityandwillidentifytheconstrainingfunction.

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When theuserasksforsomepositivequantityofaircraftforamission,thetotalcapacityoftheairfieldfo raircraftassignedtothatmissionisthesumoftheestimatereportedinthecenterportionandthelowestresidualcapacityreportedinthelowerportion.

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CaveatRegardingth eU seofAC EinThisStudyWedon othavedetai ls onairfield resources ,( inventories,avai labi l i t ies,a n duses)a tthese enrouteairf ields.Wecan es t imateground t imesbyaircraft type ,an db ymission ( typeofstop ,quanti ty ofn e e ds )ateach airf ield.Wec a n n o test imatecapaci t ies fo rresourcesn otinvest igatedby A M C .

He n c e ,o u ranalyses an df indings willnecessar i ly b e exp loratoryan dc o m p l e m e n ta ry .R A N D

ACEisapowerful,flexiblemodel. Intheanalysesassociatedwiththisstudy,however,wehavebeenabletouseonlyafewofitscapabilities,becausewehavenoinformationonthespecificresourcesavailableatanyof thebases.WehaveaccessonlytotheAirForce'sestimatesoftherampspaceorworkingrampandthefuelavailableateachairfield.Thus,wecanconsideronlyconstraintsbaseduponthoseitems.OurcontributionistouseACE'sspecificationofthegroundoperationsassociatedwitheachtypeofstopover,anditsdataonthetimesrequiredforthoseoperationsoneachtypeofaircraft,toestimatethespecificparkingandworkingcapacityofeachtypeofaircraftateachairfield.

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Th eNPS/RANDMobilityOptimizerInputs

Mo v e m e n trequi rements C o m m o d i t y codes A L D s ,R D D so n n a g e / p a s s e n g e r sOrigins,dest ina t ionsRoutes Aircraft toroute compatibil i t ies B a s e sCapaci t ies ,t iming Capabil i t ies

Fleetsizea n dm ix Bas ingNRMO Flex iblefo rmu la t ionsuppor tsvary ing ana lys isobject ives OutputsAircraftmiss ionsN u m b e r ,cargoes Routes ,t iming Aircraftbas ing ep loyments ,t iming Resource util ization Aircraft ,bases ,routes Fleetsizea n dm ix Allocat iono fa i rbase resourcesRAND

Note:LD =avai lable-to-loaddate,RD D =requireddel iverydate. Nowwewillbrieflysummarizetheoperationof NRMO.12 NRMO,likeallmodels,transformsinputsintooutputs. Requiredinputsfor N R M Onclude

movementrequirements,includingtheunitaffiliation,available-to-loaddate,requireddeliverydate,commoditycode,andnumberof tonsandpassengers. Thesedataarecommonlyinputintheformofatime-phasedforcedeploymentlisting(TPFDL);outedata,includingthenamesandlocationsoftheairfieldsandwaypointsalongeachrouteandtheaircrafttypesthatareallowedtoflyeachroute;

irfielddata,includinglocation(specifiedinlatitudeandlongitude),capacity(intermsofthenumberofnarrow-bodyand/orwide-bodyaircraftthatcanbeservicedsimultaneously),andusages(suchason-loadoroff-load,crewstaging,tankerorshuttlebeddown,recoverybase,ordivertbasefo ruseduringaerialrefuelingoperations);and

12UnpublishedRANDresearchbyL.Melody,S.Baker,R.Rosenthal,D.Morton,andP .Killingsworthon"NPR/RANDMobilityOptimization(NRMO): ANewModelfo rAirMobilityAnalysis"providesamoredetaileddescription.

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leetdata,includingthenumberofaircraftofeachtypeandthedayeachentersservice,andthecharacteristicsofeachtypeofaircraft,suchasitspayload,airspeedandallowable-userate.

Modeloutputsncludemissiondata,includingthenumberofaircraftflyingoneachroute,carryingeachcargo,eachday;

umbersandtypesof aircraftdeployedastankersandas intratheaterhaulersoneachdayandfromeachassignedairfield;tilizationinformationonaircraft,routes,andbases;andmarginaloperationalvalueof aunitincreaseineachresource.

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ConceptualFormulation NDRIg

Maximize: On-t ime deliveries + air assetsmeasure ofper fo rmance+ g r o u n dassets measure o fper fo rmanceSubject to :Meett ime -phasedd e m a n d s : byl ineidentif ication,car g otype Aircrafta l locat ion/ba lance: by type,air f ield,t ime ,fo rstrategic, tanker ,an d tact icalmiss ionsCargo /passengercapaci ty: byl ineidentif ication, aircraft type,t ime Aircraft uti l izationrates:yaircrafttype,t ime Airf ieldcapacity (MOG):yair f ield,t ime Aer ia lrefuel ing capaci ty:ylocation,t ime Cr ew availabil ity:yaircraft type,stage b as e ,t ime RAND

NR M Oattemptstomaximizeon-timedeliveries. Itaccomplishesthismathematicallybyminimizingthepenaltiesassociatedwithlateornon-deliveredcargo. Itmayalsoincludesecondaryobjectives,suchas minimizingfleetusageorcosts,orminimizinginfrastructurecosts.The majorsystemconstraintsincludethefollowing:

Meetingthetime-phaseddemand.Notethatthedemandmaybe metwithlateorevenundeliveredcargo. Thisconstraintsimplyinsuresthateverycargoisaccountedfor,anditallowsafeasible solutionevenwhendeliveriesareseverelyconstrained.

alancingequationstoensurethatthemodeldoesnotcreateordestroyaircraftorcargo.imitingcargoandpassengercapacitytoensurethatthecargodelivereddoesnotexceedthecapacityoftheaircraftdeliveringit.imitingthenumberof hoursperdaythataircraftmayfly.imitingthenumberofaircraftthatmaybeservicedateachairfieldorair-refuelingpoint.nsuringthatnoaircraftproceedswithoutarestedcrew.

Note,however,thatwithsomeminorreformulations,themodelcanitselfdeterminesomeof thesevalues.orexample,weoftenusedthe

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earlierCONOPmodeltodeterminetheminimum-costfleettosatisfyparticularscenarios.In thisstudy,wesimplyminimizethepenaltiesattachedtolateandnondeliveredcargoes.

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WeSimplifyEnRouteAirfieldStructure(1 )

Airfie ld MO G Fue lE n g l a n dMildenhall XX XX Fairford XX XXG e r m an yRheinMainRamstein XXXX XX XX Spain MoronRota XXXX XX XX

^^^^ RANDK $ & &

Onefurtherpointneedstobeaddressedbeforewegoontodiscussourfindingsthatis,tosimplifyouranalysis,wesimplifiedtheenroutestructureoftheproblem.AM Cworkedwithsevenenrouteairfields:woinEngland,twoinGermany,andthreeinSpain. Thisallowedthemtoconsider,atleastqualitatively,theeffectsof le glength(andhencetheneedforfuelandtheresultingallowablecargoloads)andweather,aswellasthepoliticalfactorsimportantinthespecificregionsoftheinvolvednations.

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WeSimplifyEnRouteAirfieldStructure(2 )NDRI I

Airfield MO G Fue lEngland Mildenhall XX XXFairford XX XX G e r m an y RheinMainRamstein XXXX XXXXSpaiiMoronRota XXXX XXXX

Airfield MO G FuelEnglandMildenhall XX XXFairford GermanyRheinMainRamstein

XX XX

Spain MoronRota XX XX

IX I'I\J w c S S S S m S S S S a

W esimplifiedthatstructure.W erepresentthesystemashavingonlyasingleairfieldineachcountry. TheoneinEnglandislocatedatMildenhallandhasthecombinedcapabilitiesofMildenhallandFairford.heGermanairfieldislocatedatRamsteinandhasthecombinedcapabilitiesofRamsteinandRheinMain. T heSpanishairfieldislocatedatMoronandhasthecombinedcapabilitiesof MoronandRota.Thissimplificationreducedthesizeofourmodelandallowedittosolvefaster,providinguswithadditionaltimeforinterpretingoutputs,reformulatinginputsandconstraints,andconductingmoreruns.Moreover,ithaslittleeffectonourquantitativefindings. T he differencesinle glengthsbetweennationsareslight,asweshallillustratelater,butarestillsignificantlygreaterthanthedifferencesbetweenairfieldswithinacountry. Weatherandpoliticsalsoprobablydiffermorebetweenthanwithincountries,butweconsideredneitherquantitativelyinthisstudy.

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S u m m a r yofO urApproach TocomplementAMC'sworkWithou rairf ield capac i tymo de l ,w e - roducemoredetailedandconsistentestimatesofairfieldcapacities andaircraftgroundtimes.With ou rairliftoptimization mo de l ,w e - irectly determineconstraining resources;-stimatemarginalcontributions ofgroundresourcesateachairfield to airliftthroughput;and-stimatebestdistributionofth egroundresourcesamongth eairfields.

W ecan there fores u g g e s tbetterrulesand a l locat ionso fscarceresourcesfo rtr ialinsimula t ions an d operat ions . RAND

Insummary,ourapproachusesACEtoproducemoredetailedandconsistentestimatesofaircraftgroundtimesandairfieldcapacities,anditusesN R M O(a)todirectlydeterminetheconstrainingresources,(b)toestimatethemarginalcontributionsofgroundresourcesspecific toeachairfield,and,aswewilldescribemorefullylater,(c)toestimatethebestdistributionof thegroundresourcesamongtheairfields."Best"meanswithintheconfinesofourmodelandourworkingassumptions.

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ThisBriefing NDKIJ

Plan:1 . In t roduct ion II . Recen tairliftstudies

III. Th eR A N D s t udy -Approachi*>Find ings

Th e1996baseline Effectsof longergroundt imesEffectsof optimizing

IV . Conc lud ing remarks

RAND Hui

FINDINGSNowlet'sdiscussourfindings.

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1996FreightDeliveriesA re Constra ined,Pa ssengerDeliver iesAreNotNDRIl

1,000 tonsof f re igh tor passengers p er day ^

1996

Freigh t RAND

The1996BaselineRememberthatweusetheMRS-BURU,MRC-Escenarioandcargoes,withmostparametervaluestakenfromAMC'srecentstudy. However,weuseourairfieldandairliftmodels.W euseonlythe1996airliftfleetandthe1996airfieldresources.W edonotmodelthe2001andthe2006scenarios.Forthe1996scenario,weestimatethatallofthepassengermovementsincludedintheTPFDLcanbedeliveredwithintheirallottedtimewindows.heaverageissome6.6thousandpassengersperdayoverthefirst30daysof theconflict.W eestimatethatallof thesepassengerscanandwillbecarriedbyCRAF(Stage2)aircraft.W eestimatethatnearly135thousandtonsof freightwillbe deliveredbyacombinationofmilitaryandCRAFaircraftoverthefirst30daysof thedeployment.hisisanaverageof 4.5thousandtonsof cargoperday.131 3 Inal lofthecasesdiscussedinthisbriefing,weassumethatAMC's1996fleetof 5C-5s,18C-17s,174C-141s,and37KC-10sisavailablefo ruse.

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IllliiNDRll

OurEstimatesofFreightDeliveries ExceedAMC's(l)1,000 tons,. of freightper day *

A MC RAND

OurestimateofcargodeliveriesexceedstheestimateproducebyAMC.heirestimatewas3.5thousandtonsperday;oursis4.5thousandtonsperday,orabout30percentgreater.Aminorportionof theremainderof thisbriefingwillbedevotedto discussingandexplainingthatdifference. Ourpurposehere,however,isnottocalibrateeitherourmodelortheirs.Mostofourdiscussionswillfocusonwaysofusingthemodelstobetterunderstandtherelationshipsbetweenairfieldresourcesandairliftflows.

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NDRIl

O u rEstimates ofFreightDeliveries Exceed AMC's (2 )1,000 tons of fre igh tp er d a y 7f -

1996

AMC RAND

Lookingcloserattheestimates,wese ethatourestimatesof bothdeliveriesbyCRAFaircraft(theupperportionsofthebars)andofdeliveriesbymilitaryairliftaircraft(thelowerportionsofthebars)exceedAMC's.OurestimateofCRAFcapacityisroughly40percentgreater. Andourestimateofmilitaryairliftcapacityisroughly20percentgreater.W hydotheestimatesdiffer?T womajorproceduraldifferencesbetweenourstudyandAMC'simmediatelydrawsuspicion: ThefirstisouruseoflongergroundtimesderivedfromACE;thesecondisouruseofanoptimizationmodelratherthanAMC'ssimulationmodel.Otherfactors,suchasdifferencesinassumptionsandinotherinputs,probablyalsocontribute,but,asjustnoted,mostofthosedifferenceswillnotbepursuedhere. Ourobjectiveinthisstudyistoexploreandcontrasttheoptimizationandsimulationprocedures,nottoproducedefinitiveestimatesofairliftcapacity.W efocusontheeffectsofgroundtimesandof optimization.

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BothOptimization an dLo ngerGround Times A reImpor tant(1)NDRII

1,000tons offreight p er day 1996

RAND/NPSMode lsA C EG r ou n d AMC Ground Timesim e s A MC Mode lsA MC Gr o u n d Times

itiiiiiiggi RANDUlli

First,let'slookatwhatourmodelwoulddousingtheAirForce'sstandardgroundimes.Thisprocedureaddsathirdestimatetoourgraph. ThecenterboxinthischartisourestimateofcargodeliveriesusingAMC'sstandardgroundimes.ThisestimateisgreaterthanAMC'sestimatebecauseitusesouroptimizationmodel. TheuseofNRMOincreasestheestimatedflowbyabout45percent.Thisestimateisalsogreaterthanourbaselineestimateabout12percentgreaterbecauseitusesAMC'sshortergroundtimes.

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NDRIl

BothOptimization andLo ngerGround TimesAreImpor tant(2 )1,000 tons of f re igh tp er day^"'"7f/

RAND/NPSMode lsA C EGr o u n d A MC Ground Timesi m e s 1996AMC Mode ls A MC Ground Times RAND EffectsofLongerGroundTimesHereweshowthoseestimatesagain,differentiatingbetweenthetwotypesofcarriers: CRAFandmilitary.Notefirstthattheincreasesbetweentheright-handcaseandthecentercasearequitesimilarfordeliveriesbyCRAFaircraftanddeliveriesbymilitaryaircraft. Bothincreasebymorethan40percent.Butthen,whenweintroducethelongergroundtimes,thedeliveriesof themilitaryaircraftarereducedfromanaverageof3.5thousandtonsperdaytoanaverageof2.9 thousandtonsperday.hedeliveriesbyCRAFaircraftremainatabout1 .6thousandtonsperday.Whyisthis?ThisisbecausetheCRAFfleetrepresentedherehasexcesscapacity.swewillse elater,CRAFaircraftcancarryonlybulkcargo,andin ourscenariotherearesufficientCRAFaircrafttocarryallthebulkcargocontainedintheflowforthefirst30daysof theTPFDL.heCRAFfleetcancarrythatcargoevenwithourlongergroundtimes.Deliveriesbythemilitaryaircraft,ontheotherhand,decreasebecausethoseaircraftarebeingusedasintensivelyaspossible,inboththestandard-ground-timecaseandthelonger-ground-timecase.Now,let'slookmorecloselyatthedifferencesingroundtimes.

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StandardGround Times NDRIl

AircraftG r ou n dTime(in ho ur s)

'12'" ; \10'4*

O P #-&

En routeAM C

RAND l^^B

ThischartshowsthestandardgroundtimesusedinAirForcestudiessinceMRS-BURU.Theyrangefrom2hoursand50minutes(C-141sandC-17s)to5hours(KC-10s)foron-loads;from3hoursand15minutes(C-141sandC-17s)to4hoursand30minutes(C-5s)forenroutestopovers;andfrom2hoursand15minutes(C-141sandC-17s)to3hoursand20minutes(KC-10s)fortheoff-loadingstopovers.

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O urGround TimesA reSignif icantlyLongerThanStandardGround Times

I W/n-I i_>'On-loaloadRAND On-loadAMCEn routeRAND

En routeAM C " ***, Off-loadRAND Off-loadAM C isa RAND HB

Nowweaddourgroundtimes,whicharesignificantlylonger,especiallyfortheon-loads. (DetailonboththestandardtimesandtheACE-generatedtimesareshownin Table1 below.)Ouroff-loadsrangefrom2hoursand45minutes(C-141s,NBCs)to5hoursand15minutes(C-5s).heseareroughly40percentgreaterthanthestandards.Ourenroutestopoversrangefrom2hoursand45minutes(C-141s,C-17s,andNBCaircraft)to4hoursand45minutes(KC-10s).heseareroughly11percentlongerthanthestandardtimes.Andouron-loadsrangefrom7hoursand45minutes(C-17s)to11hoursand45minutes(KC-10s).heseareabout150percentgreaterthanthestandards.Tose ewhytheACE-generatedtimesaresomuchlonger,weneedto lookmorecloselyatthemannerin whichACEbuildsupestimatesof groundtimefromestimatesof operations'andtasks'times.

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Table1 AircraftGroundTimes

(hours)Source,AircraftType On-load Enroute Off-loadStandardtimes74 7Cargo 5.00 3.44 3.00

NBC 3.88 3.49 3.00KC-10 5.00 3.44 3.32C-5 3.75 4.53 3.25C-17 2.87 3.23 2.25C-141 2.87 3.23 2.2574 7Passenger 3.00 1.50 3.00

ACE-generatedtimesforthisscenario74 7Cargo 8.25 4.00 4.50NBC 9.25 2.75 2.75KC-10 11.75 4.75 4.75C-5 10.75 4.50 5.30C-17 7.75 2.75 3.50C-141 9.25 2.75 2.7574 7Passenger 8.75 4.00 5.25

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A C EBuilds Ground Timesfrom ServicingOperat ions andTasks NDRIl

ktumStandardoperations:

I"--!

nnSI | lmi-fligM| (tanaraf |Nitro|) Oiyer> ||Nilrogn| I OP""a flapa.r fnapj R p l > Mission-related option

[Pf B1 Fual:sEadpa | 10. 11Un it )cargo | |L O U I | LOW!Mtgo 1 TotalAircraft Ground Urne

FullserviceStandard o para t io m :

| Pu.Ul.gM || C-w

3i~p"iU huio n-ra la tadoptions: |Wjj ~ a > ||fl|

|^ - n ^ h i ~]a o lam!

iaHmjmnjiJB.1 &m t TotalAircraftGroun d Tint R A N D !

Note:l=block- in ,BO =block-out . Aswementionedbefore,ACEcomputesaircraftgroundtimesinthreeways:singaquick-turnprofile(whichweusedinestimatingtheenrouteandoff-loadingstopovers),usingafull-serviceprofile(whichweusedinestimatingthetimesfortheon-loadingCONUSstopovers),orusingsomecustomizedprofile.T heupperportionofthisgraphicillustratesthequick-turnprofile.14tcomprises15groundoperations,severalof whichcanbeperformedsimultaneously. T hefouroperationsonthetopline(recovery,through-flightinspection,generalservicing,andlaunch)areoperationsthatmustbeperformedforeveryaircraftoneverymission.15Theotheroperationsmayneedtobeperformedonlyonsomemissionsoronlyorsomeaircraft(regardlessof theirassignedmission).he fuelingandtheaerial-portoperationsaremission-levelspecifications.Thenitrogenservice,oxygenservice,andrepairoperations,ontheotherhand,areaircraft-levelspecifications. Finally,thede-icingoperationisbothamissionandanexpected-valuespecification. Itsneed,asapercentof theaircrafton themission,isexplicitlyspecifiedbytheuserforeachmission.14Theseservicingprofilesandmanyof theservicing-operationtimeswereestablishedfo rusby CaptainAndreGernerduringhisAirForceFellowshipatRAND.15Unless,ofcourse,theusercreatesacustomizedmissionprofile.

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Theunshadedportionsofthefiguresrepresentintervalsoftimeduringwhichseveralconcurrentoperationscanbeperformedontheaircraft.Theshadedareasrepresenttimeswhenasingleoperationprecludestheperformanceofotheroperations: duringblock-inandblock-out,theaircraftisstillinoperation,ifnotinmotion;fueltransfer,oxygenservicing,andde-icingareconsideredhazardousoperationsandarenormallysolated.ACEconsolidatesimesforalltheseoperationsspecifictimesorfuelingandloadingbasedonmissionspecifications,andstandardtimes(byaircrafttypeandconfiguration)ortheotherstoconstructitsestimatesofaircraftgroundtime.Notethatwedonotrequiretherepairoperationorcargoloadingtobeaccomplishedinasingleapplication: Theseprocedurescanbebrokenupforfueltransferorforoxygenservicing.hiskeepsthetotalgroundimerombecomingunnecessarilylong.Theull-servicestopoversinvolvebothmorenspectionsand,typically,longerservicingtimes. Table2showstheexpectedground-operationtimesforC-17aircraftunderbothquick-turnandfull-servicestopovers.Customizingcanbedoneinmanyways. Asoneexample,theusermightdesiretomakeaquickturnevenquickerbysettingthetimesforthethrough-flightinspectionandforgeneralservicingtozero. Thenthestopwouldconsistonlyoftheblock-inof5minutes,theoff-loadingtimewhichiscalculatedwithinthemodel,andtheblock-outof15minutes.hatis,theaircraftwouldbeintherampareaonly20 minutesplusthetimefortheoff-load.

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Table2 ExpectedGroundTimesorC-17 s

(minutes)Quick-TurnTimes Full-ServiceTimes

GroundOperation Operation Aircraft Operation AircraftStandardoperations

Block-in 5 5 5 5Through-flightinspection 42 42 Post-flightinspection 1 20 1 20 Generalservicing 20 20 30 30 Repairs 6 0 1 2 12Nitrogenservicing 1 1 2 2Oxygenservicing 7 7 1 7 1 7Pre-flightinspection 96 9 6Block-out 15 15 1 5 1 5

Subtotal 9 0 29 7OptionaloperationsFueling

Pre-fuel 5 5 5 5Fueltransfer(150,000lb) 72 72 72 72 Post-fuel 5 5 5 5

LoadingSetupaircraftforloading 6 6 6 6Setupaircraftforpallets 5 5 5 5

On-loadingpallets 32 0 32 0Off-loadingpallets 32 0 32 0

SetupaircraftforNPC 6 6 6 6On-loadingrollingstock 75 75 75 75 On-loadingotheroversized 150 1 15 1 50 1 50 On-loadingoutsizedcargo 150 115 1 50 1 50 Off-loadingrollingstock 45 1 5 45 0Off-loadingotheroversized 150 1 20 1 50 0Off-loadingoutsizedcargo 150 1 20 1 50 0

SOURCE:nputsandoutputof ACE.NOTE:heseestimatesbasedon thefollowingassumptions;e-icingisnotrequiredfo ranyaircraft; resourceshortagesdonotincreasetheexpectedaircraft-servicingtimes;

andall aircraftareparkedon emilefromtheaerialport. Se eJ.P .StuckerandR.Berg,RAND,MR-700-AF/OSD,p.vi ,fo rdetails.

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Table3ExpectedValuesortheProbabilisticOperations,C-17s

(minutes)

GroundOperationDuration,

whenNeeded

ProportionofTimeNeeded

ExpectedDuration

RepairsQuickturnFullservice

60 60

0.100.206.0012.00

NitrogenservicingQuickturnFullservice

1520

0.100.101.502.00

OxygenservicingQuickturnFullservice

45 45

0.150.38

6.7517.10

SOURCE:nputstoACE;originally fromAMC.

Asanotherexample,theusermightwishtocustomizeon-loads,perhapsperformingseveraloperationsinparallel,orperhapsusingaquick-turnprofileratherthanfullservice.W ecautiontheuser,however,againstseverelyshorteningthegroundtimes.Afteranaircrafthasflown3,000-somenauticalmiles,spendingsevenoreighthoursorlongerintheair,itrequiresatleastroutineservicingandnspection.

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ThisBriefing NDRll

Plan:I.ntroductionII.ecent airliftstudies

III.heR A N D study-Approach-FindingsThe1996baseline

Effectsof longergroundt imesEEffectsof optimizing -Allocatingcargoestoaircraft-Allocatingaircrafttoroutes-Allocatingramp& fuel to airfieldsIV .oncludingremarks

RAND

Nowlet'sexaminehowtheoptimizationmodelaffectsourestimatesofcargodeliveries.W ebeginbydiscussingthemeaningof a"good"airliftflowandhowsuchflowsarenormallyestimatedbymobilitysimulationsandoptimizations.

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NDRIlAirliftObjectives

S up p or tmajordeployments Deliversspecifiedcargos -Ont ime -Safely

Suppor totherair - t ransportoperat ionsEmployairliftassetseffectivelyan defficiently

RAND

EffectsofOptimizingAnairliftsystemmustbeabletosupportmajordeploymentsdeliveringtherequiredcargoesontimeandsafelyatthesametimethatitcontinuestosupportothernationaloperations. Todothiswithlimitedresources,itmustemploythoseresourcesaseffectivelyandasefficientlyaspossible.PlannersspecifytheirmovementrequirementsinaTPFDL,atime-phasedforce-deploymentlisting. Thislistingspecifiesboththecargoesandtheirpriorities: cargoesspecifiedtoarrivein thetheaterondayxareexpectedtoarrivebeforethosespecifiedtoarriveondayx+1.16Each"cargo,"representedona"line"intheTPFDL,canconsistof passengers,bulk(palletized)freight,oversized(larger)freight,andoutsized(fitsonlyinaC-5orC-17)freight,al lassociatedwithoneof some33commodityclassesofmilitaryresourcesandorganizations.Eachcargohasanavailable-to-load(earliest)dateandarequired-delivery(latest)date. Thesedatesdetermineitslocationin theTPFDL.16AdditionalprioritiesaresometimesassignedusingfieldsdesignatedasPOD(portofdebarkation)priority,PODpriorityadd-on,CINC's(commanderinchief's)RDD(requireddeliverydate),etc.,butthesearetreatedlesssystematically.

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Mobilitysystemsandmobilitymodelsattempttomovethosecargoesintheirprioritizedorder.

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ModelsMimicAirliftFlows Mobility simulat ions Dea lwith cargoes on e a tat imeSelectatypeofaircraftaccord ingtorules Routethataircraft accord ing to rules H a n d l em a n ycargoes ,aircraft ,routes

Mobility opt imizat ionsoo k a ta llcargoes togetherSelectb e s taircraftforeachcargo Selectb e s troute foreachtype o faircraftH a n d l efewercargoes ,aircraf t ,routes

RAND Ilium

Mobilitysimulationstypicallyworkwithcargoesandaircraftoneatatime,astheyappearintherequirementsfileandastheybecomeavailableforuse. In MASS,whenanaircraftbecomesavailable,themodellooksfo rthelocationof itspreferredcargotype,withtheearliestavailabilitydate;andthenitlooksfo rtheleast-congestedpreferredroute. Thenthenextavailableaircraftlooksforitspreferredtypeofcargo,andsoon . Thisrule-basedbehaviorallowssimulationmodelstohandlemanycargoes,manyaircraftof manytypes,andmanyairfields.MobilityoptimizationssuchasNR M O ,ontheotherhand,considerallpossibilitiesandthenselectthebestcargoandrouteforeachaircraftineachtimeperiod. Thisdifferenceresultsinmuchlargerdecisionspaces;consequently,optimizationshavebeenabletohandlefewercargoes,aircraft,androutes. Overtime,however,withcontinuingincreasesincomputingpowerandalgorithmictechniques,thesizeoffeasibleproblemshasincreasedsubstantially.NR M OsolvedthelinearproblemsreportedhereinlessthananhouronaSunSPARC20with256megabytesofRAM.hemore-complexrunsincorporatingintegerconstraintstookseveralhours.

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NRMO Allocates CargoestoAircraftEfficientlyNDRIl

1,000tons off re igh tpe r day^.

2.0f

1996

C-141 KC-10C -5 C-17 RAND

AllocatingCargoestoAircraftAswenotedbefore,N R M Oattemptstomaximizeon-timedeliveriesbyminimizingthepenaltiesassociatedwithlateornon-deliveredcargo.NR M Oattachesapenaltytoeachcargo(andtoeachportionofthatcargoassignedtoadifferentaircraft).hispenaltyincreasesinvalueeachdaythecargoislate(thatis ,estimatedtobedeliveredafteritsRDD),thusencouragingthedeliveryofcargoesintheirTPFDL-orderedsequence. Cargoesaredeliveredoutofsequenceonlywhenappropriateaircraftarenotavailableorwhenslightingadeliverynowwillallowamore-than-compensatingincreaselater.17Thisgraphshowsourestimatedcargoflowsbyaircrafttype.T heCRAFaircraftthecargoversionof the747andthenarrow-bodycargoaircrafthandlebulkcargo(thatis,cargopackedintostandardizedpallets)efficiently. Butwiththeirlowwings,highbodies,andsmalldoors,theyhandleoversizedandoutsizedcargoes(suchitemsasH M M W V s ,aircraftengines,andevenhelicopters)quiteinefficiently. Consequently,intheserunstheytransportonlybulk17Mostpenaltiesaresettoleveloffafteracertainnumberofdayssothatafewespeciallydifficult-to-delivercargodonotdisrupttheentireairliftflow.

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cargo.W eestimatethatin theserunswehavesufficientCRAFaircrafttodeliveral lofthebulkcargoes.Militaryaircraft,in contrast,withtheirhighwings,lowbodies,andwidedoors,aredesignedtoefficientlytransportoversizedcargo. T he C-5sandC-17sarealsodesignedto efficientlytransportoutsizedcargo.In thiscargo-allocationscenario,however,weestimatethattheC-5sandtheC-17shaveinsufficientcapacitytodeliverallof therequiredcargoes.Heretheydeliver70percentoftheoversizedcargoesandonly13percentoftheoutsized.Thisshort-shriftingof theoutsizedcargoesreflectsthestructuringof theTPFDLthatis,theprioritizingof thecargoesmorethananyotherfactor.uttosomeextent,whenthemodelisconsideringtheallocationofeitheroversizedoroutsizedcargoesofequallatenesstoaC-5orC-17,italsoreflectsthefactthat,forthissetofmovementrequirementsatleast,theoversizedcargoes(fully-loadedtrucksandC-5engines,forexample)carriedaresubstantiallymoredensethantheoutsizedcargoes(helicoptersandthelike). Thatis,moretonsof oversizedcargocanbecarriedthantonsof outsizedcargo,andthusthetotalpenaltyvalueisreduced. Se eTable4.Thisdepictionrepresentsthebaselineoperationof NRMO. However,ifwehavesomeinformationsuggestingthatthewarfightershaveasignificantpreferencefo routsizedcargoes,andifforsomereasontheTPFDLcan/shouldnotbechanged,theNR M Openaltiescanbeadjustedtoincreasethosedeliveries.

Table4 AverageTonsCarried,byAircraftType

(the4.5thousandton-per-dayrun)TypeofAircraft Bulk Over OutC-17 41 483C-5 243SOURCE: OutputsofNRMO.NOTE: Entriesareaveragesofthemorethan30differenttypesofcargoes(commoditycodes)carriedbyeachtypeofaircraft.

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NRMO Allocates Cargoes toAircraftEfficientlybutAllows forOtherPriorit iesNDRIi

1,000tons of fre igh tp er d ay 1996

747'CNB C C"141 KC-10 C -5 C-17

I? AK1 ftfiiii

Thisgraphdepictsthedeliveryprofilewhenwevalueatonofoutsizedcargotwiceasmuchasatonof bulkandathirdmorethanatonof oversizedcargo.CRAFaircraftcontinuetocarryal lof thebulk.ecausetheyareveryinefficientatloadingoversizedandoutsizedcargo,transportingbulkcargo,evenwhenitisvaluedless,remainstheir"bestuse."T heC-141sandKC-10s,whichcantransportoversizedbutnotoutsized,continuetodoso.uttheC-5sandC-17s,whichcantransportoutsizedaswellasoversizedcargoes,nowspecializeintransportingoutsizedcargo.nthisscenario,theytransportal lof theoutsizedcargoes.hatis,withaweightingfactorof2,1.5,and1on theoutsized,oversized,andbulkcargoes,respectively,the1996airliftfleetdeliversal lthebulkcargo,lltheoutsizedcargo,andmuchof theoversizedcargo.Butnotethatthisweightingschemereducesthetotaldeliveriesoverthe30-dayperiodby10,828tons,or byanaverageof 0.36thousandtonsperday.Whereasitincreasesthedeliveriesofoutsizedcargoby23,918tons,itdecreasesthedeliveriesof oversizedby34,746tons,atrade-offofabout1.45to1.hiscouldbegoodiftheoutsizedtonsarein factmoreimportanttothedeploymentthantheoversizedtons;oritcouldbebadiftheyarelessorevenequallyimportant.he pointhereisthatal lweightingshouldbecarefullyconsidered,insimulationsaswellas inoptimizations.

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BothOptimization andLongerGround Times AreImportantNDRI

T on s _ Weighted To n= To n A C EGround Times AMC Ground Times

RAND/NPSMode lsAMC Mode ls

_|AMC Gr o u n dTimes RANDHH

Beforewegoon ,let'slookatthisresultoncemoreandputitintocontextwithourearlierfindings. Weightingthecargoestorepresentadditionalinformationonprioritieshasreducedthedeliveriestoanaverageof4.1thousandtonsperday.hatamountisstillsignificantlylargerthantheAM Cestimateof3.5thousandtonsperday,butitis significantlyreducedfromourestimateof 4.5thousandtonsperday.IftheobjectofourexerciseistoreplicatetheAM Cestimate,wecouldproceedfurtherdownthisroad: observingwhichcargoestheAM Cmodelcarriesandweightingourinputstoprioritizethose;observingwhichaircraftareassignedwhichroutesbytheAM Cmodel,andtweakingourinputsaccordingly. W ebelieve,however,thatsimplyfollowingtheTPFDLlistingsproducesthepreferreddeliveryprofile.

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ThisBriefingPlan:

I.ntroduct ionII .ecen tair l if tstudies I I I .h eR A N D s t udy-Approach -FindingsTh e1996baseline Effectsof longerground t imesEffectsof optimizing-Allocatingcargoes to aircraft^ -Allocatingaircraftto routes-Allocatingramp&fuelto airfields

IV .onc lud ingremarks AllocatingAircrafttoRoutesNowlet'slookatthewayN R M Oassignsaircrafttoroutes.Andthenwe'llfinishupbydemonstratinghowNR M Ocanefficientlyallocatealimitedresourcelikeramporfuelamongtheseveralairfieldsinwaysthatimprovetheoverallflowof theairliftsystem.

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Al locat ingAircrafttoRoutes

From From D o v e r D h a h r a n Tota lMildenhal l, 123Ramste in, 437Moron, 213 2,953,076 2,765,2022,879 6,092 RANDt ^M

W eassumeinthisstudythatallof themilitaryaircraftloadandleave fromacommonlocationintheUnitedStates(Dover,Del.),flyto Europewheretheyrefuel,flytoacommonoff-loadingsiteinSouthwestAsia(Dhahran),flybacktoEuropeformorefuel,andthenreturntotheUnitedStates.W eidentifyenrouteairfieldsinEngland,Germany,andSpainforthemilitaryaircraft,sotheyhaveachoiceof routes,bothgoingandcoming.18Thetableshowsthedistancesinnauticalmilesthatthemilitaryaircrafttravelwhenroutedthroughthealternativeenrouteairfields. Notethatineachcasethecriticallegthele gwheretherequiredfuelloadlimitstheamountof cargothatcanbecarriedistheU.S.-Europeleg.StoppingoverinEnglandallowsthemostcargotobetransportedandrequirestheleast(total)fuel. GoingthroughSpainincreasesthelengthofthecriticallegby3percentandincreasesthetotaldistancebyaboutaquarterof1percent. GoingthroughGermanyincreasesthecritical18CRAFaircraftflyfromDovertoanairfieldinEngland(collocatedwithMildenhall,butnotcompetingwithitforresources),thentoDhahran,andthenbackthroughEnglandtotheUnitedStates.

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legby10percentandincreasesthetotaldistancebyjustover2percent.191 9 GoingthroughMontdeMarsan,Francewouldincreasethecriticalle gby4.5 percentwhileloweringthetotaldistancebyabout3.5percent.

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The"Best"RouteDepends on..NDRII

Geog r ap h y Politics W eath erType o faircraf tType o fcargo Airf ieldresources

RANDH B

In additiontodistance,selectingthe"best"routedependsonanumberoffactors,notallof whichwecanconsiderinthisstudy.Geographyisimportantbecauseitdeterminesthedistances. W edoaccountforthat.Politicsisimportantbecauseitcancauseshutdownsatairfields. W edonotaccountfo rthat. Politicsisalsoimportantbecauseitmaypreventusfromflyingovercertaincountries,andthiswedoaccountfor. Asshowninthepreviouschart,theroutesthroughEnglandand,especially,GermanymustdetoursignificantlytoavoidflyingoverItalyandthenationsof EasternEurope.Weatherisimportant butwedonotconsiderit.Aircrafttype,cargotype,andairfieldresourcesareal limportant,andwedomodelthemall.

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TheBestRoutes(1 )NDRII

C-5s C-17sC-141SKC-10S

NoCons tra in ts R a m p ,Servicing Servicing FuelR a m p Servicing

AMC's Cons tra in tsRAND

Ouranalysisofthebestroutingofaircraftthroughtheenrouteairfieldsconsistoffourcases:newithnoconstraintsonanyoftheenrouteairfields;newithconstraintson servicing,byaircrafttype,whichweexplain;newithconstraintson servicingandontherampspace availableattheindividualairfields;andnewithconstraintsonservicing,rampspace,andfuel.

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TheBestRoutes(2 )1,000tons offreightp er d ay ,^m

5 .7

C-Ss, G,SC-17S,G,SC-141S,G,SKC-10S,G,S

Noam p Fuel,RampConstraints Servicing Servicing ServicingAMC'sConstraints No cons t ra in ts

NOTE:= England;G= G e r m an y ;S= Spain . RAND^ m

Whenwehavenoenrouteconstraints,thatis ,whenweallowthemodeltoselectthe"best"enrouteairfieldforeachmilitaryaircraftoneachtriptmakestoandfromSaudiArabia,themodelroutesaircraftthroughalloftheairfields. EverytypeofaircrafthasmostofitsplanesroutedthroughEngland,butsomeofthemgothroughGermany,andsomeofthemgothroughSpain.TheTPFDLidentifies33differentcategoriesofcargo. TheAMCaircraftdataspecify"typicalloads"ofeachcargocategoryforeachaircrafttype.Andmanyofthoseloadings"bulkout"theaircraftbeforeitsliftinglimitormaximumcabinloadisreached,somarginallylongerroutesdonotreducetheamountofthosecargoesthatcanbecarried.Additionally,becausewedonot"charge"forfuelandthequantityoffuelavailableisnotlimitedinthisrun,andbecausethedifferencesintraveltimeandincycletimeresultingfromusingthealternativeenrouteairfieldsareminorandarelostinthetime-periodstructureusedbythemodel,themodeljustdoesn'tcareinthiscasewhichenrouteairfieldsareselectedbytheaircraft.Withnoactiveairfieldconstraints,weestimatethatinthiscase,the1 9 9 6airliftfleetcandeliveranaverageof5.7thousandtonsperdayoverthefirst30daysoftheconflict.

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TheBestRoutes(3 )NDRIi

1,000 tons of f re igh tpe rda y

C-55 E,G,S SpainC-17S E,G,S GermanyC-141S E,G,S England KC-10S E ,G,S Germany

No Constraints Ramp Fuel,Ramp Servicing Servicing ServicingAMC's Constraints

constraints, AMC'sconstraints RAND

Whenweimposethe"servicing"or"servicecenter"constraint,theprofileslooklikethis.Thisconstraintrecognizesthatthesupplyofservicingpersonnelfor eachtypeofaircraftislimitedandthatacriticalmassof correctlytrainedtechniciansisrequiredtoserviceandrepairthesecomplex,fragileaircraft.ThisconstraintrequiresthatalloftheC-5sroutethroughthesamecountry,thatallof theC-17sroutethroughadifferent(single)country,andthatalltheC-141sroutethroughadifferentcountry.W eallowtheKC-10s,becausesofewofthemareavailableasairlifters,toflow throughanysingleairfield.W ecallthisour"birdsofafeather"constraint.hatis,themodelselectsthe"best"routingfo reachtypeof aircraft,giventhese tofcargoes,thecharacteristicsoftheroutes,andthedifferentcapabilitiesoftheaircraft.Withthisconstraintimposed,ourmodelroutestheC-5sthroughSpain,theC-17sandtheKC-10sthroughGermany,andtheC-141sthroughEngland. But,again,theroutingsappearnottobecritical: Little differencein thetotalnumberoftonsdelivered,whichweestimatehereas5.6thousandtonsperday,wouldresultifotherroutingswerechosenorimposed.

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Th eBestRoutes (4 )NDRI I

1,000tons of freightp er day

C-5S E,G,S Spain Spain

C-17S E.G.S Germany England C-141S E,G,S England GermanyKC-10S E,G,S Germany England

No Constraints Servicing Ramp Fuel,Ramp Servicing ServicingAM C sConstraints

No constraints ,Servic ing RampServic ing

A M C'scons t ra in ts RAND

Introducingtheservicingconstraintreduceddeliveriesbyabout1 00 tonsperday.NowweseethatintroducingthesetoframpconstraintsimposedbyAMCreducesdeliveriesbyanother500tonsperday,downtoanaverageof5.0thousandtonsperday.Theseconstraintshurt. TheC-5sgoingthroughSpainsaturateitsairfieldeverydayfromthe2nddaythroughthe30thday.heC-17sandKC-10sgoingthroughEnglandfillitsairfieldeveryotherdayandkeepitatover9 0percentofcapacityontheodddays.heC-141skeeptheGermanairfieldatover90percentofcapacityeveryday.Table5belowshowstheresourcesavailableattheindividualenrouteairfieldsin1 9 9 6 .

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Table5ResourcesAvailableattheEnRouteAirfieldsn1996

AirfieldRamp

(narrow-body-equivalenthoursperday)

Fuel(milliongallons

perday)EnglandGermanySpain

24 033 61 68

1.61 1.570.82NOTE: MRC-E scenario fo r1996.

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TheBestRoutes(5 )iiliiNURli

1,000 tons of freightpe rda y

Serv icing RampT* ervic inguel,R a m p Constra ints .e r v i c i n a

A M C'scons t ra in ts

Spain GermanyEngland Germany

Constra ints Servicing

SpainermanyEnglandpainGermanyngland Englandpain

Ramp Fuel,Ramp Servicing ServicingAMC'sConstraints

RAND

Finally,imposingthesetoffuelconstraintsusedbyAM Creducesdeliveriesbyanother500tonsperday. Thisduplicatesourbasecase andourbase-casedeliveriesof4.5thousandtonsperday.his estimateisbasedonAMC'sestimatesofthecurrentlyavailablerampandfuelateachairfieldandontherequirementthatal laircraftofthesameypemaketheirenroutestopoversinthesamecountry.T heramp,orparking-space,constraintlimitstheC-5sinGermanyandtheC-141sinEngland. Butboththosefleetsconsumesubstantiallymorefuelinthosecountries,respectively,thantheywouldhavebeenableto ,hadtheybeenroutedthroughSpain.heC-17andKC-10fleets,withsubstantiallyfeweraircraft,exhaustthelimitedsuppliesof fuelinSpain,butdonotstresstherampthere.Now,asafirstcheckonitsrobustness,wecomputetheserunsagainusingtheAirForcestandardgroundtimes.

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Th eBestRouteswith A C ETimes and withStandardTimes 1,000tons of freightp er d ay

No constraints, Servicing

A MC ' sconstraints

C-5s E,G,SEngland Spain Spain Spain Spain GermanyGermanyC-17S E,G,SE,G,S GermanyGermany England England Spain SpainC-141S E,G,SEngland England England GermanyGermany England England KC-10S E,G,SE,G,S GermanySpain EnglandEngland SpainSpain

No Constraints Servicing Ramp Servicing Fuel,RampServicingAM C sConstraints

StandardGroundTimesACE __ GroundRampServicinguel,Ramp TimesServicing

RANDf e s r f M ^

T hestandardtimes(secondlinein columns2-5)donotchangetheprofiles. Deliveriesincreasebecauseof theshortgroundtimes,buttheroutingsremainthesame.nthefullyconstrainedcase,theC-5sstillstopoverinGermany,theC-17sandtheKC-10sinSpain,andtheC-141sinEngland.Asasecondcheck,wewilllookattheseroutesfromadifferentangleto se ewhathappensiftheaircraftaresystematicallymisrouted.

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ImproperRoutingReducesDeliveries NDRIl

1,000tonsoffreightp er d ay 5r-

1996 Rout ing Profi le ABC

C-141S E G SC-5s G S EC-17s S E G KC-10S S E G

Route StructuresNOTE:= England;G= G e r m an y ;S= Spain . RAND ^ B

Thegraphicshowsdeliveriesforrunsincludingthethreeconstraints(servicecenters,ramp,andfuel),butroutingtheaircraftthroughdifferentcountries.Thebestroutingof aircraftthroughairfieldsProfileAhere,withtheC-5sgoingthroughGermany,theC-17sthroughSpain,andtheC-141sthroughEnglanddeliversanaverageof4.5thousandtonsofcargoperday.ProfileBwiththeC-5sroutingthroughSpain,theC-17sthroughEngland,andtheC-141sthroughGermanydeliversanaverageofmorethan4.4thousandtonsperday. Thisisapproximatelya2percentreductionndeliveries.ProfileCwiththeC-5sroutingthroughEngland,theC-17sthroughGermany,andtheC-141sSpaindeliversanaverageof morethan4.2thousandtonsperday,ornearlya7percentreductionindeliveries.Insummary,whenresourcesarelimited,therouteschosenfo r(orallocatedto)theseveraltypesofaircraftcansignificantlyaffectthetotaltonsofcargothataredelivered.

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ThisBriefingPlan:

I. Introduct ion II .ecen tair l if tstudies III.h eR A N D s t udy -Approach -Findings Th e1996baseline Effectsof longerground t imes Effectsof optimizing-Allocatingcargoes to aircraft-Allocatingaircraft to routesEZ^-Allocatingramp&fuelto airfields

IV .onc lud ingremarks RANDfeil"' ' '

AllocatingRampandFueltoAirfieldsIn additiontooptimallyallocatingcargoestoafixedfleetofaircraftandoptimallyallocatingthoseaircrafttoafixedsetofroutes,optimizationmodelslikeNR M Ocanalsoestimatethe"best"fleet(mix)ofaircraftandthebestspecificationof theroutes.nthisscenario,MRC-East,wheretheenrouteairfieldsareal llargeinternationalairportsandwheretheportionof theairfieldanditsfuelresourcesmadeavailableto

Analyzing the Effects of Airfield Resources on Airlift Capacity

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