From Air Transport System 2050 Visionto Planning for Research and Innovation

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This report addresses the research needed to pave the way for the Air Transport System 2050. It attempts to answer the question: “what can research establishments contribute to a comprehensive long-term, strategic process of innovation which will ensure Europe is a prime contributor to the aviation world of 2050”?

Key messages

From Air Transport System 2050 Visionto Planning for Research and Innovation

• Majorinnovationwillbepossibleonlythroughafullyintegratedresearchprocessbetween research establishments and industry.

• Allpromisingtechnologiesanddriversmustbeinvestigated;futuretechnologyselection must not be done too early.

• Researchestablishmentshaveakeyroleinthecertificationandstandardizationofinnovative technologies.

• Groundinfrastructureandintermodalitymustbecomemajorfieldsofinvestigationinaddition to all of the aeronautical domains historically studied by research establishments.

50 research scientists fromCIRA, DLR, ILOT, INCAS, INTA, NLR, ONERA

contributedtothestudy50%co-financedbyEREA

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WHAT RESEARCH FOR THE FUTURE OF AIR TRANSPORT SYSTEM IN 2050? p. 5

VEHICLE CONFIGURATION p. 8

Vehicleconfigurations:shapingthefuture p.8

AircraftConfigurations p.9

Keytechnologiesfornewconfigurations p.11

Interdisciplinaryandintegrativetechnologies p.14

PROPULSION p.16

Futurepropulsion:protectingtheenvironment p.16

Technologiesbasedonclassicalengines p.17

Revolutionarytechnologies p.19

Alternativeconfigurations p.22

ON BOARD SUBSYSTEMS p.24

Revolutionaryonboardsubsystems p.24

Researchtopics:bottom-upapproach p.25

Potentialresearchtopics:top-downapproach p.27

TOWARDS FULL AUTOMATION? p.29

Theroadtofullautomation p.29

Challenges p. 30

ModellingandsafetyanalysisofthefutureATMsystem p.33

AIRPORT p. 35

Airport2050:arevolutionincapacityandefficiency p.35

Generalconceptforthe2050airport p.35

Technologiesfortheairportof2050 p.41

ACRONYMS p.43

Content

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WHAT RESEARCH FOR THE FUTURE OF AIR TRANSPORTSYSTEM IN 2050 ?WhatresearchisneededtopavethewayforthefutureofAirTransportSystemin2050?ThisisthequestionEREAtriedtoanswertodefineitsresearchagenda. Two studies were launched to attempt to answer it.

• Thefirst: EREA: vision for the future –Towards the future generation of Air Transport System,publishedin2010,investigatedfour2050aviation scenarios, describing the associated technology challenges and choices as well as recommendations where more research is needed.

• Inthesecond,theserecommendationswereincludedinthegoalssetoutintheEuropeanCommissionreportoftheHighLevelGrouponAviation Research:“Flightpath 2050: Europe’s Vision for Aviation”publishedin2011.

This report presents the conclusions of the second study.

Flightpath 2050 : Europe’s Vision for Aviation

In2011,keyEuropeanaviationstakeholdersfromtheaeronauticsindustry,airtrafficmanagement,airports,airlines,energyprovidersandtheresearchcommunitywereinvitedtocometogetherinaHighLevelGrouptodevelopavisionforEurope’saviationsystemandindustry.

Goalsforasustainableapproachtoaviationin2050:Protectingtheenvironmentandtheenergy supply (Flightpath 2050: Europe’s Vision for Aviation)

• Technologiesandnewprocedureswillbringa75%reductioninCO2emissionsper passenger-kilometreanda90%reductioninNOXemissions.Theperceivednoiseemission offlyingaircraftisreducedby65%relativetotypicalnewaircraftin2000.

• Aircraftareemissions-freewhentaxiing.

• Airvehiclesaredesignedandmanufacturedtoberecyclable.

• Europeisestablishedasacentreofexcellenceonsustainablealternativefuels,including those for aviation, based on a strong European energy policy.

• Europeisattheforefrontofatmosphericresearchandtakestheleadintheformulation of a prioritised environmental action plan and establishment of global environmental standards.

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Priority Research AreasFivepriorityresearchareas(seefigurebelow)havebeenselectedforresearchthataimtokeepEuropeattheforefrontofaviationdesign,manufacturingand operation - particularly in the area of environmental sustainability:

Othermajoradvancesarelikelyintheprovisionofenergytotheaircraft,advanced health monitoring and prognostics and adaptive, multi-purpose hardwareabletoimplementdifferenttasksdependingontheflightphase.

Towards Full Automation?Automation already features in many safety-critical aviation activities. The report highlights three main areas in which automation will be increasin-gly evident: the four-dimensional contract, air traffic management andaircraft.

AirportThe airport is at the heart of the aviation system and improvements in intermodality and infrastructure will have positive results throughout the network. Movements of vehicles on the ground will be automated andintegrated, optimised, intermodal transport systems provided, further im-provingthepassengerexperience.

Detailed descriptions of each priority research area are presented on fol-lowing pages.

Vehicle ConfigurationChanging the shape of aircraft to go far beyond current conventional configurationsperformanceisbecomingpossiblebecauseofadvancesinmaterials, computational power and design techniques. The result will be majorimprovementsinaerodynamicefficiencyleadingtomuchlowerfuelconsumption and therefore pollution.

PropulsionPropulsion ranks alongside aircraft configuration as the major game-changing area of aviation in terms of improving its environmental perfor-mance.Thissectionlooksattechnologiesbasedonclassicalenginesandalso at potentially revolutionary concepts such as Intercooled systems, Nanotechnology,RotatingDetonationEngine,PulseDetonationEngineandPistonengineinjectiontechnology.Sustainablealternativefuelssuchasnon-biofuels,biofuels,hydrogenareexaminedandthenuclearenergyis-sue is also considered for the propulsion.

On Board SubsystemsEvermorenumerousandcomplexonboardfunctionswillbecarriedoutbysoftware rather than hardware, because of weight and volume constraints.

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VEHICLE CONFIGURATIONSVehicle configurations : shaping the future

Theconfigurationofcivilaircrafthasevolvedlittlesincethe1920s.Almostwithoutexception,passengershavebeentransportedinatubularfuselage,withtheempennageattherearandtheenginesmountedeitherunderthewings,orattherear.Althoughmajoradvancesinaerodynamicsandflightcontrolsys-temshavecontributedgreatlytoimprovingtheperformanceoftheclassicconfiguration,theadventofnewdesignmaterialsanddesignprocesses,alongwitha far better understanding of the aerodynamic and structural interactions that occur in different phases of flight, are driving some radical ideas for the future.

Itisnowthereforepossibletoconsidersomeoftheenablingtechnologiesneededforrevolutionaryconfigurationsandidentifypotentialtechnicalsolutionsandtheirintegrationwithintheoverallairtransportationsystem.Sincetheseperspectivesandtheirrelatedtechnologiesarecloselylinked,asysteminte-gration-orientedapproachmustbetaken.Whethertheyaresinglesubsystemtechnologiesorcompletelynewaircraftconfigurations,studiesmustalwaysconsider integration with different levels of the air transport system.ThefollowingchapterhighlightssomepromisingaircraftconfigurationsanddifferentsingleaircrafttechnologieswhichmightcontributetotheFlightpath2050 challenges.

RecommendationsOnthesingle aircraft technology level it is recommended that research be carried out on active/passive flow control systems to further improveaerodynamicefficiencyandcompatiblehigh-liftdevices.

Further emphasis concerning materials and structures should be given to • Material-orienteddesignmethods• Integratedstructuresandintegratedfunctionsandstructures(e.g.integratedsensorsandantennas

Ontheoverall aircraft level research should focus on:• Integratedaircrafthealthandusagemonitoring systems covering structures as well as systems to increase safety by flight envelope protection, aircraftreconfigurationandon-condition maintenance capabilities

The following chart shows the different technologiescomparatively based on the level of investmentrequired(low,mediumandhigh),asafunctionoftime(2015,2025and2050)

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Regardingaircraft configurations priority should be given to:• Developmentofintegratedandinterdisciplinaryfunctionalaircraftdesignmethods,includingsystems,softwareandintegrationaspectsconsidered from the conceptual design phase• Integratedblendedwingbodyandtail-mountedopenrotorconcepts• Aircraftconfigurationswithregardtotypeofenergy(e.g.hydrogen,electricalengine…)

Efficient aircraft production is of paramount importance for the success of the European aircraft manufacturing and systems industry. Therefore efficient mass production of large, integrated, complex CFRP/metallic aircraft structures must be developed by addressing highly automated production tools and production-oriented design.Finally it is strongly recommended that there should be higher priority on overall integrated air transportation design methods, with the aircraft as the primefocusbuttakingallmainairtransportationsubstructuresandtheirinterfacesintoaccount.

Thefollowingchartshowsthedifferenttypesofaircraftbasedonthelevelofinvestmentrequired(low,mediumandhigh),asafunctionoftime(2015,2025and2050)

Aircraft ConfigurationsWepresentfiveaircraftconfigurations:theBlendedWingBodyandPrandtlwingarepotentialsolutionsforcommercialtransports,whileadvancedtilt-rotorswill improve access to city centres and offshore platforms. Finally, personal aircraft and supersonic transports are assessed.

Blended Wing BodyToday’sclassicalaircraftconfigurationsfeatureseparatestructuresforprovidinglift(wings)andcarryingthepayload(fuselage).Thisresultsinaheavierstructure,additionalwettedsurfaceandassociatedviscousdrag.Theflyingwingconfigurationisrecognizedasthemostefficientaerodynamicsolution,butpresentschallengesinmanyotherareas.Theblendedwingbody(BWB)presentsagoodcompromise.Itshigherstructuralcomplexitycould be mitigated with development of advanced composite materials and production processes.

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TheBWBalsoprovidesgoodpotentialforlarger,morecomfortablepassengercabinsandnewstoragesolutionsforbaggage,cargoandfuel.Theoperationofsuchaircraftatso-calledMegaHubswillpresentoperationalchallenges,however,affectingthedesignoftheaircraftregardingemission-freetaxiing,geometry, service access points and boarding arrangements.

Prandtl Plane ConceptFor a given wing span and lift, the Prandtl-type biplane, with wings connected at the tip,provides a theoretical induced drag reduction of about 20% during low-speed phases suchastakeoff,climb,descentandlanding.Suchaconfigurationmightbeaninterestingsolutionforshorttake-offandlandingshort-rangeaircraftwithlessrangethantoday’sAirbusA320orBoeing737.

Thepotentialbenefitofthisradicalchangeinconfigurationmightbeareductionofupto10%infuelburn,as long as weight is not increased compared to a conventional aircraft. This concept provides also newsolutions for engine integration.

Tilt-rotor aircraftTilt-rotors combine the hover advantages of helicopters with the higher-speeds of turboprop aircraft,overcoming the problem of helicopter speed being limited bythelossofmainrotorefficiencyathigherforwardspeeds.

Thenextgenerationoftilt-rotorswillfeatureapartiallytiltedwingtoimproverotorefficiencyathover.A20-passengeraircraftwouldhavehigherrangethantheBA609atacruisespeedofaroundMach0.5-closetothatofmodernturboprop aircraft. Depending on the regulatory situation, civil tilt-rotors wouldoperate as commuters between medium/large cities and for offshoreoil & gas plants, or long-range strategic-air reconnaissance applications.

Personal Air TransportFor personal air transport, short-range small aircraft provide the lowest emissions and easiest handling. Such aircraft would be operating along with others atloweraltitudesandspeeds.Anaircraftwithuptoeightseatscouldbepoweredbyanelectricmainengineandhaveall-electricsystems.Highlevelsofautomation and pilot assistance would be required.

The characteristics of such aircraft are reduced acquisition cost, reduced weight, reduced fuelconsumption, increased reliability, reduced support equipment, simpler maintenance,expandedflightenvelope,andimprovedsurvivability.Theconceptrequirestheresolutionofanumberofmajortechnologyissues,however,includingelectromechanicalactuators, environmental control and ice protection systems,and engine technology.

Supersonic business transportLinkingthegrowingbusinessmetropolisesinNorthAmericaas well as in Europe, Asia and South America with supersonicbusiness aircraft could provide a more realistic businesscase than charter and scheduled travel.

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Significanttechnologicalchallengesremain,however,andinclude:

• Developmentofhightemperaturecarbonfibrematerials• Sonicboomnoisecontrol• Easytohandle,reliableaircraft• Low-emission,high-speedpropulsion

Key technologies for new configurations

Drag Reduction

Vortex-induced drag Aircraftdeflectairdownwardsforliftgeneration,causingvortex-induceddrag,whichistypicallyresponsiblefor around a third of total cruise drag for transport aircraft. Ways of reducing it include:

Increased wingspanWingspanisthemainparametercontrollingvortex-induceddrag.Slender,high-spanwings(i.e.highaspectratio)generatelessvortex-induceddrag,butmayresultinaheavierwingstructure.Earlyjettransportsfavouredwingaspectratiosofaround8.This requires stronger structures to carry the resulting bending and torsional moments without increasing the structural mass. Tuning spanwise lift distribution with movable trailing-edge devices is promising.Therecouldbeapotential10%fuelburnimprovementifairportterminallayoutsallowedforincreasedwingspaninfutureaircraftconfigurations,butthisshouldbebalancedagainstincreasedaircraftmassandoperationalflexibility.

Wingtip DevicesTherightchoiceofwingtipdeviceanditsintegrationintotheaircraftisakeyresearcharea.Theaimistomaximiseefficiencyincruise,wheredragreductioniscrucial.Wingletsarethemostpopularwingtipdevice,andarealreadyinusedonsomeaircraft.Otherdesignsincludethewinggrid,wingtipsailsandspiroid,aswellasthewingtipturbine,whichcanrecoversomeoftheenergylossescausedbyvortex-dependentdraganduseittodriveagenerator.Wingtipdevicescouldbringcruisefuelsavingsofupto10%.

Viscous Drag reductionViscous Drag accounts for around two-thirds of total drag and is comprised of friction drag and viscous pressure, or form drag. This is currently a main area ofresearchaspotentiallymajorefficiencysavingscanbemade.

Wetted Surface AreaVerticaltailplanesaresizedforensuringlateralstability,crosswindlandingsandcomplyingwithoneengine-inoperativesafetyrequirements.Formodernfly-by-wireaircraftlateralstabilitycanberelaxedandsizingbecomesdependentontheone-engine-outscenario.

Double-hingedrudderscanreducetailplaneareabyasmuchas15%,whichmightproducea0.5%fuelburnreduction.Thiscouldbeincreasedbypassiveoractiveflowcontroldevicestofurtherincreaserudderefficiency.

Turbulent Boundary Layer Drag Current transport aircraft achieve almost fully turbulent boundary layer flow over all wetted surfaces. Although the physics of fully turbulent flow is well understood, there are still opportunities to reduce turbulent boundary layer drag.

V-groovedribletshaveshownsubstantialreductionsinskinfriction.Wind-tunnelandflighttestinghaveindicatedpotentialaircraftfuelburnsavingsofupto2%.In-servicetrialsrevealedprematurewearofribletfilms,however-anareaofcontinuedresearch.

ControllingturbulentboundarylayerswithsmartMicro-Electro-Mechanical-Devices(MEMs)onallsurfacesholdsrealpotential.Amoredetailedunderstan-dingofunsteadyturbulentsubstructuresandhowtomodifytheseactivelytoachievedragreductionneedstobedeveloped.Becauseexperimentsarevery

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difficulttoperform,pureaerodynamicsresearchneedstobecomplementedbycontinuedeffortontechnologiessuchashigh-performancecomputing(HPC)forvirtualsimulationsofnewconfigurations.

Laminar flow Laminarflowpromisesapotential5%-10%fuelburnreduction,withthebenefitsincreasingthelongertheaircraftisincruise.Whiletheaerodynamicprinciplesarewellunderstood,theproductionandoperationoftheextremelysmoothsurfacespresentschallenges.Forward-sweptwingsarebeneficialforachievingnaturallaminarflowatrelativelyhighMachnumbersandcanalsohelptopreventfuselageboundarylayersfrominterferingwiththewingleadingedgeflow.

Naturallaminarflowcanbeappliedtocomponentswithslightlysweptleadingedges,suchasenginenacelles.

Hybridlaminarflowcanbeachievedbyembeddingperforatedsuctionpanelsintotheleadingedgesofhighly-sweptwingsandtailsurfacesforaircraftflyingfasterthanMach0.7.

Newstructuraltechnologieslikemorphingleadingedgesmayenablethegenerationofliftatlowspeedsfortake-offandlandingwithalaminarflowwing.

Otherdesignoptionswouldreduceparasiticdragduetoexternalroughnessandwakesduetowindscreendesign,windscreenwipers,rainrimsoverdoors,inletandexhaustducts,anddoorhandlesetc.

Noise reductionAircraftcontributetonoisebytheiroperationalprocedures,exposedinstallationsandenginelocation.Themagnitudeofairframenoiseiscomparablewithenginenoise(fanandjet)duringtheapproachandlandingphases,anddominateswhentheaircraftisdirectlyoverhead.

The sources of airframe noise are:

• Flaps(trailingandsideedges,slots)• Leadingedgeslats• Landinggearsandwheelwells• Wingandtails(trailingedge,tips)• Fuselage(turbulentboundarylayer)

Noisereductiononaircraftisinterdisciplinary,involvingvariousaircraftsubsystems such as high-lift systems, landing gear and engines.

High-lift devicesHigh-lift devices are significant sources of noise. Naturallaminarflowwingsimplyfewerhigh-liftdevices.Oneofthemostpromising technologies is to replace slotted flaps and slats by closedand smooth surfaces, but this would result in wings which do notproduce the same lift as multi-element airfoils, so additional technologieslikelocalflow-controldeviceswillneedtobedevelopedtoavoidflowseparation.

Landing GearAn advanced low-noise main landing gear might feature: • Telescopicside-stay• Streamlinedlegdoorfairing• Upstreaminstalledtorquelinkwithfairing,noarticulationlinkneeded• Bogiefrontfairing,brakefairing,hubcapsandwheel/tyrerimin-fills

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Weight reduction: a key driver for efficiencyMinimisingaircraftweight isakeydriver forefficient transportation, so technologiesenabling thisareofgreat interest.Within theACAREVision2020programmeapotentialoverallmassreductionof30%hasbeenenvisaged.However,singlelightweightmaterialswillnotbesufficienttoachievesuchachallenginggoal.Moreintegratedinterdisciplinaryapproacheswillbeneededsuchas:

• Integrateddesign• Materials-relateddesignandefficientlocaluseoflightweightmaterials• Productionoflargeintegratedpanels• Efficientassembly

Three principle directions can be derived from these opportunities: • material-orienteddesignmethods• integrationofdifferentmaterialssystems• adequateproductiontoolsandprocedures …inparallelwiththedevelopmentofnewmaterialsandintegratedstructures.

Integrated structural design Compositematerialsandmanufacturingtechnologiesallowforthedesignofmoreintegratedstructureswithfewerfasteners,reducingweight.Otheradvan-tages compared to metals include fatigue damage resistance, corrosion resistance and thermal insulation.

Thedrawbacksofthesematerialsare,ingeneral,theirsensitivitytoimpact,limiteddamagetolerancepropertiesandlowelectricalconductance.Compositesalreadyrepresentupto50%ofthestructuralweightforthemostmoderncommercialaircraft,suchastheBoeing787andAirbusA350.

Aeroelastic tailoringAircraft wings are designed such that their shape yields optimum lift and load distribution, but these values vary as the wing is deformed during flight. Ae-roelastic tailoring can generate wing designs that deflect under loading in such a way as to moderate the internal load increase. Composites are particularly usefulforthistypeofdesignbecause,byorientingfibresinspecificdirections,thestiffnesscharacteristicsofthestructurecanbedesignedtogivepreciselythedeformationresponsetotheexperiencedloadingtoachievetheoptimumwingshape.

Self-healing materials Astructurally-incorporatedabilitytorepairdamagecausedbymechanicaluseovertime.Currentresearchoncompositematerialswillexpandthescientificunderstanding of self-healing materials and introduce the cradle-to-cradle concept for thermoset-based plastics and composites.

Material-related structural designLifecycleassessmentstudiesofenvironmentalemissionshavedemonstratedthebenefitsofstructuralaircraftcomponentsmadefromlightweightCFRPincomparisontoaluminiumandGlassLaminateAluminiumReinforcedEpoxy(GLARE),expressedinfuelconsumptionandCO2emissionsandtakingintoaccount their “cradle-to-grave” emissions.

Besidesincreasingtheamountofcompositesintheairframestructure,furtherweightandfuelburnreductioncanalsobeachievedbyfurtheroptimisingcurrent composite structures in terms of cost and performance.

Unconventional fibre lay-ups / elastic tailoringLightercompositestructurescanbeobtainedthroughimprovedlocaldirectionalstiffnessproperties.Thiscanbeachievedbylocalelastictailoringofstruc-turesusingadvancedfibreplacement, incombinationwithadvanceddesign,analysisandoptimisationmethods, including“as-manufactured”materialdetails in the design loop.

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Windowless cabinAircraftwindowsinthepassengercabinandcockpitcontributetoweightanddrag.Aradicalsolutiontoreduceweightmightbereplacingthewindowswithlightweight low-power-consumptionscreenswithpassenger-selectableviews.This technologywouldmeanthatunusualaircraftconfigurationssuchasBWBsandflyingwingscouldbeconsidered.

New materialsComposite materials have the potential to provide for the integration of components and other items such as antennas, sensors and actuators into the struc-ture.Insomeareas,however,metallicstructuresareseenasmorebeneficialintermsofstiffnessandproducibility.

Thermoplastic compositesMostcarbonfibrecompositescontainthermosetpolymers(mainlyepoxy)forthematrixmaterial.Toenhancedamagetoleranceandtoughness,thermoplasticpolymerscanbeused,whichcanbeheated,meltedorsoftened,reshaped,andthencooledtoafinalhardenedshape,makingthemeasytoreworkandrepair.

Nano-technologies for improved material properties Furtherimprovementofcarbonfibrecompositesproperties,inparticulartheirbrittlenessandfracturesensitivity,canbeachievedbynanomaterialadditivessuchasgrapheneplateletsorcarbonnanotubes.Strength,stiffnessandresistancetofatiguecrackpropagationgainsofseveralordersofmagnitudehavebeendemonstrated.Moreover,thesignificantlyimprovedelectricalconductivityofthecompositematerialsovercomestheneedforlightningstrikeprotectionsystemsusuallyachievedbycopperorbronzemeshesinsertedinthelaminate.

Interdisciplinary and integrative technologies

Production technologies: large integrated panels

Compositematerialsandtheirrelatedmanufacturingtechnologiesprovidetechnicalandeconomicalenablersfornewaircraftconfigurations.Larger,inte-gratedstructuralelementswithcurvedshapescanberealizedusingcarbonfibrereinforcedplastics.

Althoughsomeexperiencehasbeenachievedoverthelast20-30years,efficientproductionintermsoftoolingandproceduresremainstobedeveloped.Automatedfibreplacementandfilamentwindinghasenabledadvanced,economicallyviablemanufacturingofcompositematerialstructures,butforone-shotcompositecomponents,thefinalassemblylineprocessmustbeadaptedtocompositematerials,whichhavelessductilityandhigherstiffness.

On-Line Aircraft Health and Usage Monitoring

Aircraftoperationalbehaviourcanbeimprovedthroughefficientdamageandfaultdetection,maintenance,andlogistics.Forthis,real-timeassessmentofthecompositestructurebyintegratedstrainmonitoringsystems,basedonnetworksoffibreopticsensors,canbeapplied.Abetterunderstandingofstructuralbehaviourduringflightmayleadtoareductionofdraglossesbyusingstrainreadingstoadjustdeformationduringflightortoimprovethesafetymarginsused in the design process. Strain readings from critical parts of the structure could monitor damage or damage growth during flight.

This information could be used to develop an integrated aircraft health and usage monitoring system, which enables the overall aircraft state to be assessed. Such a system would require high reliability, intelligent sensor data gathering, sensor fusion and analysis, and the development of appropriate action pro-cedures.

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PROPULSIONFuture propulsion: protecting the environmentTheturbofanenginespoweringtoday’saircraftareapproachingtheiroptimumintermsofefficiencyandonlymajorchangesinaircraftconfigurationand/orpropulsion concepts will bring step changes in fuel burn and emissions.

Whilethereisstillplentyofscopeforfurtherimprovementsinturbofantechnology,themajorenginemanufacturersandresearchinstitutionsareworkingonalargesetofradicalsolutionsforthenextgenerationofshort/mediumrangetransports,whichaccountformostfuelconsumption,andhenceemissions.Theattractionofmajorfuelsavingsisbalanced,however,bysignificantchallengesonnoise,complexityandpassengeracceptability.

Promising technologies

In the short term, continuing development of turbofans will continue to reduce fuel burn, noise and emissions. It is clear that a step-change will berequiredtoachieveanyfurthersignificantfuelburnimprovement,andalloftheenginemanufacturersarelookingatpotentialsolutions,oneofthe principal research areas being contrarotating open rotors. Such engines are not seen as suitable for long-range aircraft, however, and geared fans and other approaches are being considered.

Electric propulsion of unmanned aerial vehicles and small aircraft is a real possibility in the medium term.

Sustainable alternative fuel concepts must become a priority for aeronautics.

Biofuels will contribute to emissions reductions and are already being evaluated in commercial transports. For the longer term, studies into emissions-free hydrogen fuel continue.

The following two charts compare the different technologies based • onthelevelofinvestmentrequired(low,mediumandhigh)andasafunctionoftime(2015,2025and2050)and• onthetypeofaircraft(UnmannedAirVehicle,PersonalandCommercialTransports).

Technologies versus Investment/Time

17Technologies based on classical engines

Enginemanufacturersareconstantlyworkingtoimproveengineefficiency.Workcurrentlycentresonraisingthebypassratiowithnewfanconfigurations,andimprovingthethermodynamicefficiencyofthecore.Thereisalsomuchpotentialforimprovingtheperformanceofaircraftpistonengines.

Contrarotating open rotorContrarotating propellers driven by an advanced core are mountedat the rear of the aircraft, offering up to 30% lower fuel consumptioncompared to the most advanced turbofans available today.

Becauseoftheirlargediameter,openrotorengineshavenofancowlings. While saving weight and reducing drag, this removesan important noise-shielding device, so that other ways haveto be found to reduce the noise caused by the interaction ofthecontra-rotatingblades.MaximumcruisespeedsarelimitedtoMach0.8.

Contrarotating fanHigherfanefficiencyandreducedenginediameterreduceenginedrag, reducing fuel burn and emissions. A dual-stage, statorlesscontrarotating fan replaces the single-stage fan and stators.The pressure rise across the fan is split between the two stages,reducing the number of blades per stage and allowing for higheraxialflowMachnumbers,reducingfan(andthereforeengine)

PROPULSION

Technologies versus Investment/Aircraft Type

AIRBUSgenericOpenRotor–CleanSkyEUproject

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diameter,engineandcowlingweight,anddrag.Alternativelythebypassratio,andthereforepropulsiveefficiency,canbeincreasedwithoutincreasingenginediametercomparedtocurrentengines.Fanefficiencyisincreasedby2-3%comparedtoconventionalengineswithgearedordirectdrivefans.

The fan generates higher noise because there is less space for acoustic treatment and a planetary fan drive system is necessary, which also adds weight andcomplexity.

Intercooled systemsAnintercooled,recuperatedenginewouldhaveverylowspecificfuelconsumptionandemissions.Asincreasesincomponentefficienciesbecomemoredifficulttoachieve,changingthethermodynamiccycletoincreasethethermalefficiencyoftheenginecouldreducespecificfuelconsumptionbyupto30%over conventional turbofans, with associated emissions reductions.

The intercooled recuperated engine uses an intercooler and recuperator to achieve a change in the cycle. The intercooler is placed within the compressor, whereitminimisesthepowerrequiredtocompressairbyremovingtheheatfromthecompressedairwhileheatingthebypassairflow.Therecuperatortakesheatenergyfromthecoreexhaustandtransfersittothehigh-pressuresectioninfrontofthecombustor,reducingtheamountofheatneededtoburnfuel.

Nanotechnology Nanotechnologyenablesengineerstocoatbladeswithmultipleprotectinglayers,providingacost-effective,impenetrablelayerwhichissothinthatneitherweightnordimensionsaresignificantlychanged.Gasturbinecompressorbladesaresubjecttocontinualerosionfromparticulatemattersuchaswaterdroplets,dustandvolcanicashsuckedintotheengine.Thiscausesagraduallossofefficiency,leadingtoincreasedfuelconsumption,reducedpowerandhigherpollution.Operatingcostsareincreasedbecauseoftheneedtoreplacetheblades.

Coating blades with a protective barrier is cheaper and easier than replacing them, but the coatings must be tough, to withstand corrosion over a long ope-rating periods, and lightweight, to preserve aerodynamic performance.

Rotating detonation engineBurningfuelwithdetonativecombustionresultsinamuchlargepressurerisethancanbeachievedinaconventionalcombustionchamber.Therotatingde-tonationenginehasaverycompactcombustionchamber,producingashorter,simplerengine.Thehighpressurerisebringsimprovementsinefficiencyandthereforefuelconsumption,aswellasemissionsbenefits.Researchisconcentratingonfuelmixture,initiationandpropagationofdetonationinacylindricalchamber.Preparationsareunderwaytotestagasturbineenginefittedwithcontinuouslyrotatingdetonationcombustionchamber.

Continuousinjectiontechnologywouldprovideasimplersolutionforfuelcombustion,aswellashigherthrust,inbroaderoperatingconditions.LowerNOXemissionsareonelikelyoutcomebecausetheenginecanoperatewitheitherleanorrichfuelmixtures.

Pulse detonation enginePulsedetonationenginesintroduceapulseddetonationinaclassicalgasturbinecycle.Thedetonationproducesasupersoniccombustionshockwave,theresultingveryhighpressureincreasebeingsuchthatthehigh-pressurecompressorcouldbereducedinsizeoreveneliminatedaltogether.Fuelsavingsofupto10%couldbeachieved,dependingonturbineefficiency.

Twofamiliesofpulsedetonationenginehavebeenidentified:

• Thehybridversion,basedonaclassicalgasturbineinwhichthecombustionchamberisreplacedbytubulardetonationchambersclosedbyvalveson the upstream side and open on the downstream side facing the turbine

• Thecombustionwaverotorengine,whichhascloseddetonationtubesandcombinesdetonationwithadynamicpressureincreaseachievedby compressionwavesgeneratedinthetubesbytheclosingandopeningofentryandexitdoors.

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Piston engine injection technologyHigh-pressure,veryfastdirectinjectionsystemshavepotentialapplicationingeneralaviationandmilitaryaircraftsuchastacticalunmanned-aerialvehicles(UAVs).Thesemultimodeenginesrunondifferentfuels,orgas,andcancontinuouslyadjusttheirmixturetoadapttotheload,whilecompressionratiocanbe varied by introducing alcohol for high load regimes.

Featuresincludehigh-velocitypiezoelectricservovalveswithultra-shortactuationtimesofafewmillisecondsandinjectionpressuresincreasedbyafactoroftenfromthecurrent2,500bar,drasticallyreducingNOXandotheremissionswhileretainingthebasicenginedesign.Biofuelsareparticularlysuitableforsuch engines.

Revolutionary technologies

Anumberofevolutionarytechnologiesarebeingstudied,coveringallpropulsiondisciplines.Biofuelsareamongstthemostpromisingfuelsintheshorterterm for reducing emissions, with hydrogen a longer term possibility. Electric power in various forms is attracting increasing interest as the necessary tech-nologiesmature.Forspecialisedultra-high-speedairvehicles,ramjetsandscramjetsareunderdevelopment.

Sustainable alternative fuels

Non-biofuelsInnovative ideas for non-biofuels are beginning to emerge, such as fuel produced from agricultural waste products, solid waste or from industrial waste gases likefumesproducedbythesteelindustrycontainingcarbonmonoxide(e.g.LanzaTechgas-liquidfermentationprocessthatconvertsCOinalcoholwhichcanbeupgradedinhydrocarbon).Thereisalsothe«solartoliquid»pathwaythatcouldbepromisingiftheprocessisdemonstrated.

Biofuels

Biofuelscouldbringreductionsofupto15%ingreenhousegasemissions,aswellashelpingtosecurefuturefuelsupplies.Enginelifetime,fuellinginfras-tructureandfuelconsistencyconsiderationsmeantheywouldhavetoreplaceconventionalkerosenewithnomodificationstotheexistingsystem.

AssumingtheCO2releasedduringcombustionisbalancedbythatextractedfromtheatmosphereduringcultivationthroughphotosynthesis,CO2emissionscould be virtually eliminated.

The main biofuels under consideration are biologically-obtained hydrocarbons and biohydrogen.A third generation, based on algae, is another possibility.

Themostpromisingstate-of-the-artfuelsarebasedonbiomassorwastefeedstockandHydroprocessedRenewableJet,bothcertifiedasa50%blendforuseinaviation.These are quite close to compatibility with current engines in terms of energydensity, viscosity and temperature. All of the technical detailsare manageable, and standardisation can be achieved using mineralorbio-additives.Thereis,however,muchtobedoneinthefieldofgeneticengineering to decode and enhance biomechanisms able to deliver different sorts of biofuels, additives and lubricants.

Hydrogen

Hydrogencanbeburnedinajetorinternalcombustionengines,orusedtopowerfuelcellswhichgenerateelectricitytodriveapropeller.Thehighenergycontentpermassunitwouldbringsignificantpayloadandrangeincreases,andemissions,particularlyCO2,wouldbevirtuallyeliminated.

Liquidhydrogenhasnearlyfourtimesthevolumeforthesameenergyoutputaskeroseneanditshighlyvolatilenatureprecludesstorageinthewings.Mostdesigns therefore store hydrogen in the fuselage, leading to a far bigger fuselage volume than for conventional aircraft. The performance of a hydrogen-fuelled aircraftisthereforeatrade-offbetweenthelargerwettedarea(andhencedrag)andthelowerweightofthefuel,andthisdependsonthesizeoftheaircraft.

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Completeredesignoftheaircraftandoftheglobaldistributioninfrastructurewouldbenecessaryandhydrogenandexistinginfrastructureswouldhavetoco-exist.Anotherchallengewouldbetodevelopsustainablesuppliesfromindustry.

Liquidhydrogenat-253degreesCrequiresheavyinsulationofinfrastructure,heatexchangerstoincreasefueltemperaturebeforecombustingandatotallynewaircraftconfiguration.Onanenergy-for-energybasis,liquidhydrogenisconsiderablymoreexpensivethanfossilfuels.

Electrical propulsion

All-electric aircraft All-electric aircraft use electric motors instead of internal combustion engines.Power comes from fuel cells, ultracapacitors, power beaming,solar cells and/or batteries.

Researchisconcentratingondevelopmentofadvancedtechnologiessuchas superconducting or liquid hydrogen-cooled cryogenic motors for lightweight,high-performancemotors.Electricmotorsaremoreefficientandrobustthanconventionalengines and do not lose power at altitude. They are also quiet and emissions-free.

Energy-efficient storageHighlyefficientenergystoragedevicescouldbringadvancesingeneration,conversion,distributionandstorage.Potentialsolutionsincludeharvestingenergyfrom vibrations, using thermo-acoustic engines for energy conversion, actively controlling airflows for better energy distribution, and flywheel energy storage.

Energy harvesting devices can be used to capture the energy in unwanted vibrations. They include conventional, miniaturised devices as well as micro devicesthatusenovelmethodsofenergyconversion.Examplesincludemicroheatengines,andmicrofuelcells,bothofwhichhavepowerdensitiescom-parabletolarger-scalepowerplants,aswellasmorenoveldevicessuchasmicro-electro-mechanicalsystems(MEMS),piezoelectricdevices,photovoltaiccells, and biologically-inspired energy conversion devices.

Battery powerOneofthesolutionstopoweringaircraftwithelectricmotorsistoproducetheenergyonthegroundandstoreitinonboardbatteries.Forlargeaircraftthesizeandweightofthebatteriesremainsexcessive.However,forsmalleraircraftelectricpropulsionappearsmoreaccessibleandhasalreadybeenappliedsuccessfullyintheYuneecE430lightaircraft.BoeinghasproposedcombiningelectricpropulsionandgasturbinepoweronthesameaircraftinitsSUGARstudy,whichcouldsolvetheissueofthelargepowerdensityrequiredfortake-off.

Fuel cellsFuel cells are becoming a viable option to power electric motors for small aircraft, and to generate electricity for the more-electric-aircraft architecture increasingly present in commercial aircraft.

Fuelcellsarealsomodularandtheoreticallyanyvoltageorpowercanbeproducedbyaseriesand/orparallelconfigurationofstacksofcells.Technologiesunderconsiderationincludetheadvancedprotonexchangemembrane(PEM)andsolidoxidefuelcells.

ThepossibilityofusingaPEMfuelcellstackprovidingthetotalpowerneededbytheengineandalltheauxiliarysystemshasbeendemonstratedinlightair-craft, using commercial fuel cell and power management technologies, albeit with reduced speed, climb rate, range and payload-carrying capability. The ma-jorchallengeistoreducethesizeoftheelectricdrivepropulsionsystem(mainlyfuelcell,motorandpowermanagementsystem)andtoincreaseefficiency.

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Photovoltaic fuel cellsPhotovoltaic fuel cells are a promising technology especially for high-altitude long endurance unmanned air vehicle and small aircraft. To be competitive, costsneedtobereducedbyuptoafactorfive.Atpresentmostofthesolarcellmarketisbasedoncrystallinesiliconwafers,butthereisnowmajorinterestinthin-filmsolarcells,withfilmthicknessesintherangeof1–2μm,thatcanbedepositedoncheapsubstratessuchasglass,plasticorstainlesssteel.

The development of suitably light, powerful batteries is still several decades away. Solar-powered aircraft powered solely from the heat provided by the sun arebeingtested,butclearlywouldnotbesuitablefor24-hourdeployment.

Hybrid electric turbineHybridelectricturbineswouldusetheexcellentthrust–to-weightratioofaturbineengineforhigh-powerrequirementssuchastake-offandelectricalpowerforcruiseanddescent.Cycleanalysishasshownthatagoodcompromisecouldbetoinstalla4MWelectricmotoronthelow-pressure(LP)shaft.Theaddi-tionalpowerwouldbeactivatedduringcruisetoreducethepowerdemandontheLPturbine.Asimplecyclesimulationshowsthatwhen50%ofthepowerrequiredtodrivethefanisprovidedelectrically,specificfuelconsumptionfallsby21%.

Theratioofjetfueltobatteriesdependsonthemission.Short-rangeflightswouldusemorebatterypower,whilelong-rangemissionswouldbemainlykerosene-fuelled.Therequiredelectricmotorandbatteryperformancesarecurrentlyunavailable,butcouldbewithinthe2050timeframe.

High-speed propulsionResearchonhigh-speedaircraftcapableofreducinglong-rangeflightstobetweentwoandfourhourshasbeenongoingforseveralyears.SpeedsofMach4–Mach8arenecessary,ataltitudesfrom24km–30km,whichpointtowardsadvancedhigh-speedairbreathingenginessuchasramjetsandscramjets.

WithintheEuropeanUnion’sLong-TermAdvancedPropulsionConceptsandTechnologies(LAPCAT)project,theoreticalandexperimentalstudiesonthede-sign of two high-speed concepts, equipped with dual-mode airbreathing and hydrogen-fed propulsive systems, are being performed in order to demonstrate their feasibility for long-haul flight.

Low NOX combustor ramjet Combustionoftheair-hydrogenmixturerequiredforthepre-cooled(LAPCATII)ramjetengineresultsinhighlevelsofNOXproduction,witharesultingunac-ceptableeffectontheozonelayer.Thethruster-combustordesignisthereforecriticaltothefutureofthisconcept.

Rich-burn,Quick-mixLean-burn(RQL)combustionappearstobepromising.Itinvolvestwo-stagecombustioninwhichallofthefuelisinjectedinthefirststage,reactingwithafractionoftheairflowandresultinginafuel-richmixture.Inthesecondstagetheremainingairismixedwiththemainflowandreactswith the remaining fuel in a fuel-lean combustion process.

MHD scramjet AstrategyforimprovingscramjetperformancecouldbebasedontheMagneto-Hydro-Dynamic(MHD)bypasssystem.MHDscramjetspromiseincreasedcombustionefficiencyandstability,withmorecompactdesignofthescramjetpropulsivesystem.Feasibilityhasstillnotbeendemonstrated,however.Combustorefficiencyiscriticaltooverallthrusterperformanceandthereremainsdoubtastowhethertheconceptispossiblewithoutexcessiveaero-dynamic drag.

Nuclear propulsionNuclearpropulsionwasstudiedinthe1950s,mainlyformilitaryapplications.Theresearchdemonstratedthata200-tonneaircraftrequiredan80-tonnereactor,ofwhich70%oftheweightwastheshield.

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Nuclearwastetreatmentisaparticularlysensitiveareaforaircraftbecauseoftheriskofcontaminationfollowinganaccident,andpublicperceptionofthedangersofnuclearpower.Researchshouldthereforeconcentrateonthisareafirst.

Onthebasisofthelikelydirectioninwhichnucleartechnologywillevolve,coupledwithenvironmentalconcernsandpublicperception,itseemsclearthatnuclearpropulsionforciviltransportationisnotpromising.However,itshouldbeinvestigatedinordertoquantitativelyclarifythetechnicalissues.Specificpotentialapplicationscanbeidentifiedasoverseascargocarriedaboardunmannedseaplanesorlong-endurancepilotlessaircrafttoreplaceorcomplimentsurveillance satellites

Alternative configurationsNewmaterialsandmanufacturingtechnologyareincreasingthefeasibilityofnewaircraftconfigurations,suchastheBlendedWingBodyaircraft,openingpossibilitiesformajorpowerplantinstallationimprovementsbringingsignificantreductionsinfuelburnandemissions.

Embedded propulsion

Distributed/embeddedpropulsionplacestheengineswheretheycanpartiallyortotallyingesttheairframeboundarylayer,reducingdragandmakingthedownstream flow of air more uniform.

ABlendedWingBody(BWB)configurationdistributesthrustgenerationalong the wingspan by using several embedded, or buried, small engines.Propulsion can come from two or more engines. Ideally, a higher number, ingesting the entire boundary layer, would be used. Poor fan performance at the boundary layer indicates an optimum of three or four engines and two conventionally-mounted engines. Thebaselineisaconventionalturbofan,butwithagearboxtoreduceenginecoresizeandlow-pressureturbinesize.Thecoreengineisthenusedtome-chanicallydrivethethreefanswhich,fora300-passengeraircraftwouldhaveadiameterof1.2m.

Thelowerweightandnoiseandhigheraerodynamicefficiencyofthissolutioncouldproduceapotential54%fuelburnreduction,noiselevels46EPNdBbelowICAOStage4andNOXemissions81%belowCAEP6.Economically,smallengineshavelowerdevelopment,productionandmaintenancecosts.Also,becausethenecessarythrustwouldbeachievedwithanumberofequally-sizedsmallenginesitmightbeexpectedthatonlyafewsmallenginetypeswouldneedtobedeveloped,whichwouldopentheproductionandmaintenancemarketstoawider,morecompetitivemarket.

Solar energy to improve combustion

TheBWBconfigurationoffersanopportunitytocovertheupperwingsurfaceswithphotovoltaicelements.Atechnologybreakthroughwouldbesolarcellpaint,andsomeconceptshavealreadybeendevelopedanddemonstrated.Suchalayer,appliedtothecarbonfibrematerialsfromwhichthewingwouldalmost certainly be built, would have the additional advantage of improving the electrical properties of the airframe as well as increasing resistance to light-ningstrikes.

The electrical energy from the solar cell paint would be converted into high voltage/low intensity pulses which would be applied inside the combustion cham-bertoincreasetheenthalpyofthegasimpingingonthehigh-pressureturbine,increasingthethermodynamicefficiencyoftheenginecore.

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ON BOARD SUBSYSTEMS

Revolutionary on board subsystems

Aircraftsubsystemsprovidefunctionsforthecrew,passengers,aircraftandairtrafficmanagementsystem.Becausetheyinvolvemanyfieldsofexpertiseandtechnology,afulllistofpotentialsolutionsforthesubsystemsof2050islikelytobeincomplete.Researchwhichcanrealisticallycontributetothe2050goals will therefore be characterised more by evolution than by revolution.

The term “subsystem” is mainly related to one or several interacting electric, electronic and electro-mechanical on board equipments which support “sys-tem” functions or pneumatic/hydraulic equipment related to on board actuation systems.

The study is based on top-down and bottom-up approaches:

• Bottom-up approach: Thisapproachsurveysexistingaircraftsystemsandanalysesthemforanypossibilitiesforradicalimprovements

• Top-down approach: Thisapproachanalysesthe“EREAvisionforthefuture”andtheEC’s“Flightpath2050vision”documentsforpotentialsystem implications.Italsolooksatrevolutionaryideasintheotherdomainstodeterminethesystemstechnologyneededtorealisethoseideas

Main areas for the development of on board subsystems

All-weather flight at all timesSystems which support the pilot, or in unmanned vehicles, the autonomous flight management system, to fly in all-weather conditions at all times require on board presentation of meteorological data and the technologies necessary for enhanced and synthetic vision to support flight in low-visibility conditions.

DatalinksAlargeincreaseinhigh-speeddatalinkusageisforeseen,whichwillrequireonboardsubsystemstechnology.Importantaspectsaretheincreasinglystrin-gentrequirementsonsafety(integrity,reliability,availability)androbustness.

Revolutionary energy technologiesRevolutionarynewwaysofsupplyingenergytotheaircraftwillrequireonboardsubsystemstechnologyinmanyareas.Apartfromreducingtheenergyconsumptionorenvironmentalfootprintofindividualsystemsandofthecompleteaircraft,areasofinterestinclude:efficient,power-denseandrecyclableenergy storage systems, energy generation and energy control/management.

Advanced health-monitoring and prognosticsReduction inaircraft lifecyclecosts,andthatofonboardsystems,canbeachievedby improvedmaintenance,supportedbyaircrafthealth-monitoringsystems. These enable long-term scheduled maintenance to be replaced by on-condition-based maintenance.

Meta-systemsTheever-increasingcomplexityofsystemsandfunctionsbringsaneedforresearchintoeffectiveandreliablemeta-systemswhichprocessandinterpretthedata of many systems at a higher level. A combined flight management system for manned and unmanned aircraft can be foreseen, which shares decisions between the navigation system and the ground operator.

Systems engineering: advances in methods, processes and toolsDevelopmentandcertificationofnewaircraftsubsystemsinvolvesmeetingsafetyandreliabilityrequirements,callingformethods,processesandtoolsrelevant to systems engineering rather than technology development. The development of sophisticated tools supporting the development process will be as important as the development of new technologies.

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Large-scale automationLarge-scaleautomationoftheairtransportsystem,asexpressedinmultiple2050visions,willrequireamassivedistributedcontrolsystem,whichwillbeextremelycomplex,involvinglarge-scaleintegrationacrossmultipledisciplines.

Standardisation and modularisationFortechnologydevelopmentingeneral,opensystemsandstandardsareimportantbuildingblocksthatallowmodularisation.Here,aroleisseenespeciallyforresearchinstitutesbecauseoftheirindependency.Whilestandardisationisnotinitselfexpectedtobeusefulasastand-aloneresearchtopic,eachtopicshould have standardisation as a goal.

Adaptive, reconfigurable, multi-purpose hardwareOneofthechallengeswillthereforebetoenablebasichardwaretobereconfigurable,sothatitcanimplementdifferentfunctions,dependingontheflightphase. For non-safety-critical equipment, the weight and volume of dedicated electronic equipment will be replaced by basic, “general-purpose” electronic boards.

Research topics: bottom-up approach

Thedevelopmentofanewaircraftsubsystemhastosatisfysafetyandreliabilitycriteriaifitistoachievecertification.Suchrequirementscallformethods,processes and tools relevant to systems engineering rather than to technology development.

Thedevelopmentofsophisticatedtoolssupportingthephasesofadevelopmentprocess-design,verification,testing,etc-willbeasimportantasthede-velopment of new technologies. The applicability of new technologies will be conditioned by the availability of processes and methods to certify the related equipment.Asanexample,thereisthepossibleuseofartificialintelligencetoachieveforfullautonomy.Nowadays,functionsusingartificialintelligencecannotbecertifiedbecauseoftheirunpredictability.Ifwedonotelaboratenewwaystostatethereliability,andconsequentlythesafety,ofsuchnewparadigms,technologies based on them will no be useable.

Technologies alone are not enough. In parallel, system engineering methods and tools have to be developed in order to apply those technologies in the aeronautical environment.

Anoverviewofresearchtopicsdefinedfollowingthebottom-upapproachisproposedbelowwithinanon-orderedlist.

Reconfigurable communication systems

Developmentofdataandvoicecommunicationsystemsbasedonreconfigurableunits.Bybasingthemonacommonhardwareplatform,severaladvantagescouldbeexpected:

• Shortertime-to-market

• Lessweightforredundantcommunicationssystems.

• Lessequipmenttoloadonboard.

Disadvantagesincludecertificationissuesofthereconfigurationfunction,especiallywhenexecutedduringtheflight.

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Adaptive communication systemsCommunication systems which can adapt some transmission characteristics as a function of the environment include:

• embeddedradiochannelstobestallocatethefrequencyofoperationwithinacertainfrequencyband• adaptingtransmissiondataratetotheavailablepowerandcommunicationdistance• adaptingthemodulationschemetothetransmissiondatarateandsignaltonoiseratioatthereceiver

Greaterflexibilityandadaptabilityofcommunicationsystemscanallowinhabitedairvehiclestooptimisemissionsautonomously.

Conformal antennaeAntennae which are conformal to the aircraft fuselage would reduce drag, weight and cost.

Enhanced Vision SystemsEnhanced vision systems can provide safe navigation of both manned and unmanned aircraft. They are especiallyusefulduringtake-offandlandinginlowvisibilityconditionsandtopreventrunwayincursionsbyclearlyidentifyingrunways,taxiways,otheraircraft,andpeople.Duringapproachtheyimprovedetectionoftrees,powerlinesandotherobstacles,improvevisibilityinbrown-outconditionsandinhazeandrainandhelpidentifyruggedandsloping terrain

Synthetic Vision SystemsSynthetic vision systems enhance situational awareness and flight safety during critical flight phases. Innovative displaysystems give the pilot additional information and eliminate distractions arising from using a head-down display.

Combiningsyntheticandenhancedvisionsystemswouldgivethepilotfullawarenessoftheexternalenvironmentregardless of visibility.

Vision-based UAV taxiing and autolandingUAVautonomytofollowtaxiwaysanddetectobstaclescoulduseEVSsensorsandanactivesensorsuchasLIDAR,orlaserscanner.Reliabilityofasensor-baseddetectionsysteminanautomatedcontrolloopisanissue.LandingwithlittleornogroundcooperationwouldgreatlyincreaseUAVautonomy.

Fuel cells for auxiliary power unitUseofhigh-efficiencyfuelcellsforauxiliarypowerunitswouldimproveenvironmentalbehaviourandbemorereliablewithrespecttointernalcombustionenginesandelectricgenerators.Lowenergy-to-weightratioisanissue.

Powerline data communication in aircraftApowerlinedatacommunicationnetworkcarriesdatabysuperimposinga modulated carrier signal on a wiring system. Also used for electric powertransmission and to distribute digital data and electrical power to smartsensors/actuatorsandonboardcomputers.Reducestheweightofdatacables, while maintaining the reliability of wired connections.

Wireless in-aircraft data communicationA wireless data transmission channel for communication between aircraftsystems and personal electronics devices would reduce the weight of cablesand is an enabler for passenger data communication.

Disadvantages include susceptibility to electro-magnetic interference, as well as signal degradation due to materials in the aircraft in the transmission path (e.g. a/c structuralpartsorotherobjects).Securityisalsohardertoachieve.Certificationmaybeachallengeascommunicationofsafety-criticaldatamustnotbecompromised.

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ONBOARDSUBSYSTEMS

Highlevelgoals Higher BetterATS Reduce Reduce Higher Flight ATS capacity / cost of impact on flight security Researcharea safety availability flying environment comfort

Systemsengineeringandadvanceddesign,certificationandmanufacturingtools

Flight predictability: A computer providing a dynamic model of flight evolutionCommunicationofsuchdatabetweenaircraftandground-basedtrafficmanagementtodetermineanoptimum(4D)trajectory

Sensors for on board weather forecasting

Advanced health monitoring and prognostics systems

Subsystems to identify performance degradation of systems (navigationsensors,commandsystem)andflightenvelopedegradation

Onboardsystemarchitectureandcertificationphilosophyforapilot-lessaircraft

Sense and avoid

Sensors to rapidly detect and predict wind conditions

Subsystem technology to support close-formation flying for the purpose ofdrag reduction

Cockpitdisplaytechnology,pilotinteraction,voicecontrol,synthetic/enhancedvision

Systems to handle emergency situations at a higher level

Secureandrobusthigh-speeddatalinksforaircraft-to-groundandpossiblyaircraft-to-aircraft communications

Subsystem technology to support all-weather operations. Aspects include:anti-iceandde-icesystemsfornewaircraftmaterials(e.g.composites).

Subsystem technology to support active flow control strategies

Subsystem technology to support active load control strategies

Subsystem technology to support structural morphing for drag reduction

Powerelectronicstocompetewithexistingtechnologies(bleedair,hydraulic)ontopicsasspecificweight,reliabilityandcost.

Revolutionaryenergytechnologies:storage,generationandcombined

Energy harvesting

Crash-safe nuclear power plant

Highcruisealtitudeaircraftrequiringnewenvironmentalcabinandoxygensystem.

Subsystemtechnologytosupportactivereductionof(outside)noise

Potential research topics: top-down approach

Forthetop-downapproach,higher-levelvisionsoftheairtransportsystemin2050andconceptsdevelopedintheotherdomainsofthisstudy(aircraftconfiguration,propulsion,automation,airport)havebeenusedtodeducetheneedfornewaircraftsubsystemstechnologies,andthereforetheneedforsubsystemsfutureresearch.

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TOWARDS FULL AUTOMATION?

The road to full automation

Theevermorecomplexairtransportsystemfacingmoreandmoreambitiousgoalsisnaturallyevolvingtowardsautomation.Whateverthedegreeofauto-mation,theATMsystemwillcontinuetocomplywithitskeyperformanceareas:servicelevel,environment,safetyandsecurity,increasedcapacity,airlinecost,flexibilityandpredictability.Theaimhereistodefinethebiggestchallengesinthepathtowardsahighlevelofautomation,fullautomationrepresentingthe ultimate evolution. Ahighlyautomatedairtransportsystemisbasedonthreepillars:the4-dimension(4D)contract,automatedairtrafficmanagementandautomatedaircraft.

Four-dimensional ATM contractThe4DATMcontractisthecentraloperationalconceptenablingtheglobaloptimisationofairtrafficmanagement.ItprovidestheframeworkforautomatichandlingoftheflightmanagementofallairtrafficparticipantsbyacentralATMsystemensuringsafeseparationandoptimisationofallflights,accordingtoglobal performance criteria.

A4Dcontractcanberepresentedasatimedimensionmovingalongwithathree-dimensionalairspacetubeassignedtoeachaircraftbytheATMsystemand/ornegotiatedbytheaircraftthemselves.Allaircraftmuststaywithintheirassigned4Dvolumes(i.e.respecttheircontracts)fortheentiredurationoftheflight.Aslongastheydoso,theyareguaranteedconflict-freetrajectoriesandtheentireairtrafficsystemisgloballyoptimisedtotheextentofthecapabilityof the central system.

All4DcontractsaregeneratedbythecentralATMsystem(strategicplanning).Eachcontractisissuedfortheentireflight,includinggroundoperations,andisconflict-freeinrelationtoallothercontracts.Theaircraftareinchargeofexecutingtheircontractsandthegroundsystemmonitorsthem.Undercertaincircumstances,suchasemergenciesoroff-nominalsituations,thecontractcanbeupdatedon-boardtheaircraft(dynamicplanning).

The implementationofa4Dcontract-basedATMsystemwillbringsignificant improvements togroundandon-boardsystems,bothon technologyandconceptual levels.

Automated air traffic managementEnsuringthattheairtrafficsystemhastotalsituationalawarenessunderallweatherconditions,includinglowvisibility,requiresarangeofsensorstodetectaircraftmovements,movementsofothervehicles,andaviewofallotherrelevantobjects,likebirdsanddebrisontherunway.Asaresult,controltowersatthe airport will no longer be necessary and will be replaced by remote towers.

Anautomatedconflictdetectionsystemactsimmediatelyonceaconflictisdetected.Theactionwillnotinvolvethe«controller»–ascalledtoday–butwillbenotifiedtotheaircraftorvehiclesinvolved,whichwillautomaticallytakeappropriateaction.

ThetransitiontowardsautomatedATMhasbeenongoingforseveralyears.Airspacesectorsarebigger,directroutingisreplacingstrictairwaysandcontrol-lersaresupportedby4D-planningtoolsinordertoincreaseefficiency,predictabilityandthroughput.

Thistransitionwillcontinue,ultimatelyresultinginashiftfromahumandecisionmakersupportedbyassistancesystemstowardsadvancedautomateddecisionsystemsmanagedbyahuman.Ontheway,challengesarefoundonthehuman-machineinterface(HMI)levelandlegalissues.

Automated AircraftBy2050,the«pilot»(ascalledtoday)willmonitortheaircraftinsteadoftakingactiveactions.

Theaircraftisattheheartofthefully-automatedATMsystemandwillhavetoaccomplishallrequiredtaskssafely.

Thekeyaspectofaircraftautomationisacompleteimplementationofthe4Dcontractsconcept.However,thetransitionphasewheretherewillbeamixedtrafficofautomatedandnon-automatedaircraftneedstobethoroughlyinvestigated.

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Aircraftwillberesponsibleformonitoringtheircommitmentwiththeir4Dcontract«signed»withthegroundATMcentre.Incasesinwhichitisimpossibletofulfilthecontractorinanemergency,theaircraftwillbeabletodynamicallyupdateitsplanningandwillinformthegroundATMcentreofitsactions.

Thus,aircraftwillhavetocollectandmanageinformationonotherairtraffic,weather,communications,navigationandsurveillanceinfrastructurestatus,airports,terrainandobstaclesandcontinuouslychecksubsystemstatustoperformreal-timeevaluationsoftheircapacitiesandperformancelimitations.

By2050,airborneautomationshouldbeadvancedenoughfor:

• Adaptive4Dtrajectorymanagementandon-boardre-planningcapabilityfornegotiatingtrajectorieswiththegroundsystem• Acomplete,orextended,sensorfusionsystem,derivingnavigation/controldatafromallon-boardsensorsystems• Comprehensivehealthmonitoringofsystemintegrity

Pilotswillbeassignedwitharolequitedifferentfromthecurrentone.Theywillbekeptintheloop,but(similarlytotheairtrafficcontrollerintheforeseenautomatedATMsystem),willmonitortheoperationinsteadoftakingactiveactionsandcommandovertheaircraft.Thus,wewillnottalkaboutpilotsandcontrollers anymore but about managers and supervisors.

Challenges

Enablingtechnologiespavingthewaytowardsfullautomationarealreadybeingstudied,butmanyarestillat lowoperational levels.Naturally,theshifttowardsfullautomationwillnothappenovernight,butwillratherbeanevolutioninwhichmoreandmoretasksareexecutedbyautomatedsystems.

Thefigurebelowshowsaschematicoverviewofpossibletechnologicalevolutiontowardsahighlevelofautomation.

Developing realistic models Creatingsufficientlyrealisticmodelsforresearchisamajorchallengeassystemsbecomemorecomplexandinteractive.The biggest challenge lies in testing the interaction betweenelementsofthesystem.Newmodellingtechniquesandmethods to validate models will be necessary to buildtheATMsystemofthefuture.Standardizedmodelsthatallow coherent and comparable testing at different siteswouldbeamajorstepinATMsimulation.Asdifferentmodels could be compared more easily, the developmentcycleofnewtechniquescouldbenefitasdecisionsaboutthe most promising techniques become much easier.

Human-machine interface Themainchallengeindesigninganextgenerationhuman-machineinterface(HMI)forATMisdecidingwhichinformationnotto present. As the potential amount of information will be huge,onlyinformationthatisnecessaryfornext-generationcontrollerstoexecutetheirtasksshouldbepresented.Advancedmonitoringtoolswillbenecessarytoverifyiftheplanningisproperlyexecuted.Incaseaproblemarisesthatcannotbesolvedbytheautomatedtools,theATMmanagerwillneedtobebroughtintheloopbypresentingtherightinformationsuchthathecanmakeadeliberatedecision.

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Interoperability and data collectionThepathtowardsfullautomationputshighdemandsonthetimelyavailabilityoftherightdataintherightplaceattherighttime.AsthecurrentATMsystemconsistsofahugenumberofincompatiblesystems,interoperabilityisamajorchallenge.Systemswillneedtobeinterconnectedanddatashouldbesharedandmadeavailableamongstakeholdersusingstandardizedprotocolsandformats.

Data miningAsmoreandmoresystemsbecomeinterconnected,itisimportanttobeabletolocateandextracttherightinformation.Newdata-miningalgorithmsareneededtosupportdataextractionandselection.

Sensor fusionCurrentonboardandoffboardsensorsprovideawealthofinformation.Oftenthisinformationis(partially)overlapping.Sensorfusionaimstocombinethevarious sensor information sources to provide a single, optimised, view of the world. For the future, innovative sensor fusion algorithms need to be developed whichareextremelytolerantofanysystemfailure.Situationalawarenessmustbeguaranteedinallweathersconditions,alltimes.

Innovativesourcesofdatawillbecreatedwhichofferaccurateweatherforecastingbeforeandduringtheflight.NewSARtechnologies,molecular/opticalair data sensors and multiple magnetometers for advanced attitude determination will have to be developed. Such technologies will enable fully automated operationswithlowcost,weightandsize.However,moreonboardcomputationalpowerwillberequiredforreal-timeimplementation.

4D contract: ground Automatedglobalstrategicplanningwilllaythefoundationsforaglobalapproachtoairtrafficmanagementwhichprovidessafeseparationofaircraftaswellasmaximizingcapacity,whileminimisingcosts,delaysandenvironmentalimpact.

Strategicplanningaimstofindglobalsolutionsforallcontractsassignedtoaircraftinalargeairspace(suchasEuropeorUSA).Ittakesintoaccountallsignificantfactorsandgeneratesasetofcontractswhichofferthebesttrade-offsbetweenallthemainkeyperformanceareas.

Torepresenttheinterestsofallaviationstakeholders,thesystemwillusetheprincipleofcollaborativedecisionmaking.However,asthesystemwillbeorientedtowardsagloballyoptimalsolution,eachstakeholderwilltakepartinthecollectivedecisionprocessbyinputtinghisowncriterion.Thesystemwilluseanefficientmultidisciplinaryandadaptiveoptimisationmethod,includingallrelevantcriteriaintheplanningofcontractsandadaptingtothedynamicnatureoftheATMwherechangesinthenumberanddomainofthesolutionvariablesarefrequent.Currentlythetrafficmanagementandflightmanagementtasksaredistinctconceptswhichcorrespondtodifferentphasesofgroundplanningactivity. It islikelythatatsomepointthetwowillbeunified.Flightmanagementactivitywillbeintegratedwiththesameautomatedglobaloptimisationprocesswhichinitiallywouldsolvetheairtrafficmanagementproblem.

Eventuallythegroundplanningcentreswilltakechargeofcalculatingandassigningnewoptimisedcontractsevenaftertake-offasfactorschangeon-boardandintheair(suchasweather,airportclosures,emergenciesetc.),ensuringtheglobalATMsolutionremainsoptimisedandsafeforthedurationofeachflight.

4D contract management: airborneUnexpectedchangesinmeteorologicalconditionsordegradationineitheraircraftorsystemsperformance,couldpreventanaircraftfrommaintainingits4Dcontract.

In such cases, as normally envisaged, a “tactical” re-planning process would be used and a new contract agreed between the ground and airborne segments.

Thedistinctionbetweenacontractandatrajectoryshouldbeexplained.Acontractrepresentsthespace-timereservedportionassignedtoanaircrafttocompleteitsflight,whilethetrajectoryistheactualpaththeaircraftwillfly(whileremainingwithinthecontractually-definedairspace).

Thecontractwillbedefined,throughastrategicortacticalplanningphase,onthegroundor,incertainemergencyconditions,onboardtheaircraftthatwillimmediatelyinformtheATMsystem.Trajectorymonitoringandcontrolwithintheassignedcontracttubeistheresponsibilityoftheaircraft.

TOWARDSFULLAUTOMATION?

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Automated airport operations

Passenger travelInafullyautomatedairport,passengerinteractionwithairportstaffforcheckin,baggagedrop-off,security,bordercontrol,andboarding,willdisappear,oratleastbeminimallyexperienced.

Someprocesses,liketheformalcheckinprocedure,willdisappearcompletely.Manypassengersalreadytravelwithelectronicboardingpasseswhichareuploadedtotheirsmartphonesanddonotneedtophysicallycheckin.Researchonlessvisibleandlessintrusivesecurityprocessesisongoing.

Aircraft handlingTheairportwillbeabletomaintainasustainablecapacityunderallweatherconditions.Thismeansaircrafthandlingprocessesneedtobemoreefficient,with reduced runway occupancy and gate handling times.

Aircraftwillbefullyintegratedwiththeairtransportsystem,their4Dflightsplannedthroughoutthebusinesstrajectory.Aircrafthandlerswillbefullyinformedaboutthestatusofeachaircraft.Delayswillbereducedtoaminimum,sothatthepredictabilityofoperationsincreases,improvingtheefficientplanningofresources.

Where infrastructure allows, aircraft handling can be performed in the intelligent infrastructure. Automated boarding bridges, electrical power supply (if still necessary),andfuellingfrompumpslocateddirectlybelowtheaircraftwillreducedependenceonhumanresources.Personnelstillrequiredwillbeequippedwith hand held devices providing all necessary information about the status of the aircraft.

Connection between aircraft and passengerPassengerboardinganddeboardingwillneedtobemoreefficient,withfullyautomatedprocessesduringwhichtheyarekeptinformedonthestatusoftheirflight(andviceversatheaircrafthandlershouldknowthestatusofeachpassenger).Specialattentiontothelocationofindividualpassengerswillbenecessary for those who are transferring to another flight.

Full automation will require fully operational individual passenger planning systems that will enable the aircraft to be informed of the status of each passenger takingtheflight.

Intermodal transportGlobaloptimisationcanonlybeachievedbybroadeningtheconcepttowardsintermodaltransporttotheentiretransportsystem.

Theaimistoincreasetheefficiencyoftheoveralltransportchainbyimprovingtheinteroperabilityofdifferentmodesoftransport,increasingenvironmentalsustainabilityandmakingmoreefficientuseoftheexistinginfrastructure.

Interconnection of the air transport system with land and sea surface transports is mandatory. This interconnection will be carried out at physical and mana-gement levels. The physical level involves airports and other transport systems, while management, through a centralised integrated transport management system,willprovidecommunicationsandinterconnectionamongthedifferentstakeholdersatstrategic,tactical,andoperationallevels.

Health monitoringTo achieve a high level of autonomy and support the wide delegation of responsibilities to on-board systems, the development of advanced health monitoring systems is required.

Maintainingtheperformance-basednavigationsystemattheheartofthe4D-contractconceptwillrequirespecialattentiontothedevelopmentofalgorithmswhich can identify performance degradation of systems such as the navigation sensors and the command system.

A further aspect is the development of systems for vehicle and system diagnostics to watch for trends which indicate a potential forthcoming failure.

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Emergency handling Today, flight procedures are subdivided into normal, abnormal, and emergency situations.

In a highly automated environment, systems should contain built-in rules to handle abnormal and emergency situations. Statistics indicate for more than half ofallaircraftaccidentsasreasonhumanerror,soitisreasonabletoaskwhetherthesystemitselfortheresponsiblehuman-in-the-loopmanagershouldrespond to abnormal situations.

Aviation systems are usually designed as human-assistance systems which provide advisories to the operator. In the future, fully automated systems will decideandexecuteactions,andtheoperatorwillhaveamanagingandsupervisingtask.Ifanerroroccurs,thehumanwillbeabletointervenetosolveproblems the system is not able to solve.

Fullautomationwillenablemoresystemstobeoperatedwithfewerhumans(i.esinglepilotcockpit,singleEuropeansky),althoughthiswillreducethesituational awareness of an operator for a particular emergency. If humans are supposed to handle these situations, it is essential to identify how the operator shouldfocusonitinanefficientandsafeway.

On-board planning and optimisationFlight planning capabilities at the tactical level could be carried out on-board to address or support some relevant functionality, such as separation manage-ment, or a particular flight condition, such as flying with degraded performance.

As far as separation management is concerned, there will be further delegation of separation responsibility to provide tactical conflict resolution avoidance ofweather,airspace,terrainandotherhazards.Specificalgorithmswillresolveconflictsatleastseveralminutesaheadofpredictedconflicts.Theresolutionmanoeuvre is usually very small and generally includes course, speed, or altitude changes.

Ingeneral,a4Dcontractassignedtoaself-separatingaircraftwillbesufficientfortheaircraftmission.Afteranunplannedmanoeuvre,theaircraftwouldbeexpectedtoreturntoitsoriginalroute(orcontract).Incaseswhereitisrequiredtomoveasignificantdistancefromtheoriginalcontractanew4D-contractcould be negotiated.

Thedevelopmentofalgorithmsforon-boardtrajectoryplanning,autopilotingandflightcontrolsisalsorelevanttocontinuouslyadaptthetrajectorytoma-noeuvres occurring as a result of malfunctions.

Modelling and safety analysis of the future ATM system

TheintroductionofnewproceduresandtechnologyinacomplexsystemsuchasafullyautomatedATMsystemneedstobeappropriatelyevaluated,bothfromperformanceimprovementsand,aboveall,fromasafetyriskassessmentpointofview.

TheATMsystemisa“systemofsystems”,thatisaseriesofindividualinteractingentities,eachoneacombinationofcontinuousdynamics(e.g.aircraftdynamics)anddiscretetransitions(e.g.pilotdecisions/autopilotmodes/ATCactions).MethodologiesandtechnologieswillthereforehavetoaddressthedevelopmentofefficienttoolssupportingamodellingapproachfortheproposedcomplexfutureATMsystem,alongwithperformanceandsafetyverificationinrealistictrafficscenarios.

TOWARDSFULLAUTOMATION?

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AIRPORTAirport 2050: a revolution in capacity and efficiency

Theairportof2050mustbedrivenbythedualrequirementsforincreasedcapacityandimprovedefficiency.Airportlocation,layoutandequipmentwilltakeinto account environmental concerns as well as passenger comfort. Airports must also function with the highest possible levels of safety.

Fourmaindriversfortheairportof2050havebeendefined:

Environmental

Dramaticreductionsofemissions(CO2,NOX)andperceivedexternalnoisewillbeessential.

Capacity

Airportsareacriticalcomponentoftheairtrafficsystemandtherearereliablepredictionsthattheywillhavetocopewithhighernumbersoftrafficandpassengers.

User comfort

The main goal for 2050 is fast, reliable and comfortable door-to-door travel, independent of the mode of transport. This passenger-oriented air transport sys-temwillbefocussedontime-savingthroughreduceddelaysandqueues,alongwithcomfortableanduser-friendlyprocedures.Optimal,reliableconnectionsbetweendifferenttransportmodeswillleadtosignificantreductionsintraveltimes

Safety

Theexpectedincreaseinairtransportisverycloselyrelatedtothetrustpassengershaveinthesystem.Onlywiththehighestlevelofsafetyregardingsys-tems, operators and procedures can the 2050 goals be achieved.

General concept for the 2050 airportThe following are seen as critical elements:

• Airtrafficmanagementwillberelatedtoanetwork of airports rather than local and individual airports

• Landsideandairsidecomponentsneedtobe re-thought and intermodal means of transport described

Evolutions of the airport.The different concepts are related to one or several drivers: environment, user comfort, capacity and safety

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The airport networkTheairportsof2050willbeintegratedintoanetworkofair,ground and even water transport that will enhance capacityandmaketransportationmoreefficient.Theairportnetworkwill be mainly composed of hubs connected to secondaryairports that will provide services to a greater number ofusers and operators.

Overall concept of hubs & secondary airport connections

Connectionsbetweenhubsandsecondaryairportswillbepossiblebymeansofefficientandenvironmentallyfriendlypublictransport,butwillalsoincludeanoptimisednetworkforprivatetransportationthatwillenabletheefficient,safeuseofpersonalgroundtransport.Shipsmaybeusedtoconnectsecondaryairports, depending on their location.

Airtransportwillincludecurrent-configurationaircraft,plusotheractorssuchaspersonalairtransportationvehiclesoraircraftwithpassengerspre-loadedintostandardfuselageboxes.Inaddition,differenttypesofrunwaysaswellastake-offandlandingassistancesystemswillbeavailabletoprovideservicesforconventionaltake-offandlandingaircraft,short-takeoffandlandingairvehiclesorconvertiblevehicles.Airportnetworksshouldbedesignedtoaccom-modate them all.

Interconnectionswithinthisnetworkwillbeprovidedbymultimodaltransport,includinghigh-speedtrainsforthenationalorinternationalnetwork,trains,subways, tramways or suburban trains at regional airports, electric ground vehicles, environmentally friendly ships or even air-buses.

A passenger-oriented airport

The2050airportwillusenewtechnologiestomakepassengers’stayintheairportasshortandcomfortableaspossible.Oneofthemostimportantchallengeswillbeachievingpublicconfidenceinautomation,althoughthiswilldemandsignificantadvancesintechnology.

Automationwillmeanthatusersareinformedaboutthecurrentstatusoftheirjourneyand alternative options, periodically or on demand. Information points will be distributed aroundthe terminals and interactive devices embedded in transport systems so that passengers canaccess travel information at any time using smart phones or interactive panels/screens situatedalongtheintermodaltransportnetwork.

OperationsBy2050,theSingleEuropeanSky(SES)four-dimensional(4D)airtrafficmanagementsystemwillhavebeenfullyimplemented.Itwillbeimportanttoprovideairportnetworkswiththecapabilitytocoordinate/managegroundoperationswith4Dairborneoperations.

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Within this timeframe, several scenarios could be envisaged:• Commercialaircrafttoorfromhubs.Passengerswouldaccessairportsusingtheintermodaltransportsystem• Personaltransportsystemstoorfromsecondarydedicatedairportsconnectedwiththehomebyair-railtransportation• Hubandsecondaryairportsconnected,enablingpassengersusingpersonalaircrafttoreachthehubandtransfertocommercialaircraft.

Information Handling and Collaborative Decision MakingAnintegralelementoftheairportofthefutureisthehandlingofinformationandthecollaborationofallinvolvedstakeholders.TotalAirportManagement(TAM)willbeexpanded,theroleofoperatorschangingfromtacticaltopre-tacticalandfromspecializedcontrollingfunctionstomulti-systemmanagement.Coordinationoftheoverallnetworksystematairportsandbetweenairportswillbenecessary.Decision-makingwillbesupportedbyhigh-performanceau-tomated systems operating on an enormous amount of data providing statistical analyses, overview of the actual situation and prediction of the future. With theautomationofmoreandmoreprocesses,theamountofdatathatneedstobehandledwillincreasesignificantly.Newstructuresandconceptsofdatahandling will therefore need to be developed.

Airside operationsIntheshortterm,theairsidewilltakeadvantageofimprovementsresultingfromtheSESprogrammeandwillevolvetowardshigherautomation.Theairportinfrastructurewillincluderevolutionaryarchitectureadaptedtoanynewaircraftconfigurationandpropulsionmode(i.eblendedwingbodyandnewfuels,suchashydrogenorbiofuels).Newairportlayoutsandrunwayconfigurationscouldovercomeweatherrestrictionsandmaintaincapacity.Arevolutionaryairsidedevelopmentcouldbeacircularrunway,adaptedtoanywinddirection,toincreasecapacity.Associatedtoaterminalcenteredinthe‘circle’,suchrunwayswouldenableshort,fuel-savingtaxiingalongradiiadaptedforcapacityandsafety.

Runways

CapacityRealoractualcapacityisusuallylowerthandeclaredcapacitybecauseofweatherrestrictionsanddependenciesbetweenrunways.Currenttrendsinairportrunwayoperationswilloptimisetheuseoftheexistingrunwaysystemthrough:

• ImprovedplanningresultingfromSESARtrajectory-basedoperations• Increaseduseofnoiseabatementoperations• Capacityincreasesfrombetterunderstandingofwake-vortices,enablingreducedseparationandnewapproachprocedures

Location and size of runwaysRevolutionaryconceptstosavespaceand/ortoenableoperationstoalleviatepressureoninhabitantsinclude:

• Remoterunways,possiblyinthesea• Largerunwaysurfaces,enablingoperationsfromanydirection• Largecircularrunwaysenablingoperationsfromanydirection• Double-deckrunways• Airportsinthesky(cruiser–feederconcept)

Operational proceduresRevolutionaryconceptstoenablemoreefficientrunwayusageinclude:

• Formationflyingorpairedarrivalsononeorseveralrunways• Moreentranceandexitpointstoonerunway• High-precisionapproachsystemstoallowreducedseparationthrough flying different approach paths towards one runway

AIRPORT

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Landing and take-off powerRevolutionaryconceptsforreducingenginepowerduringtake-offandlandinginclude:• Catapultedtake-off• Railsystemandground-basedelectricpowertoacceleratetheaircraft• Railsystemorland-basedcartsystemtoland• Tractorbeamforlanding• Arrestercablestohelpbraking

All-weather operationsRevolutionaryconceptsfortheincreaseofcapacityindependentofweatherconditionsinclude:• Onboardequipmentallowinglandingwithsignificanttailorcrosswinds• Onboardequipmenttodisplayweatherinformationandairportinfrastructureinlowvisibilityconditions• Fansorotherequipmenttoblowfogandwaketurbulenceaway• Ground-basedrunwayheating

Taxiways and ApronsElectric taxiing

Electrictaxiingcanbeachievedwithanelectrically-powerednosewheel,orelectricvehiclescalledtaxibotsconnectedwiththeaircraftnosewheelandoperatedfromthecockpit.Aircraftenginescanbeshutdown,leadingtoreducedfuelconsumptionsandemissions.Suchvehiclescouldbedrivenautono-mously and fully automated.

Electric EnergyToreduceemissions,fossilfuelscanbereplacedbyelectricalpowergeneratedbymoreenvironmentally-friendlymethods.Amajorchallengeistheprovisionof the large amounts of energy needed to operate all of the vehicles and to guarantee its availability at all times and under all weather conditions.

Power generation using solar or geothermal systems needs to beintegrated into the future airport infrastructure.Terminalscouldhavelargesolarpanelsontherooforonairfieldareas not used for aircraft or ground vehicles.Wind farms could generate the necessary energy for offshoreairports.

4D Trajectory Operations on the groundGround-handlingmanagementsystemswillbeabletooptimisetheallocationofground-handlingvehicles.Withfullyavailablehigh-speeddatalinkcom-munications, relevant information between all actors at the airport is shared instantly. All areas are equipped with wireless access points to ensure data availability.Newdatalinkconceptswillhavetointegratedifferenttechnologiesusingconventionalgroundandsatellite-basedcommunicationsystems.ThereisalreadyavisionforthisintheSESARprogramme.

Landside operationsTheairportlandsideistheinterfacebetweenairtransportserviceproviders(airlines,airportsetc.)andthepassengers.Therefore,futurelandsideinfras-tructureandservicesmustfocusonpassenger’sneedsandcomfort.

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Futureairportterminalswillbemuchlesstimeconsumingforthepassenger.Oneexampleisatcheck-in,whichdoesnothavetotakeplaceinsidetheairport,but can be performed at home, at the hotel or using a smart phone.

Airportterminalswillhaveshortwalkingdistancesforpassengers.Movingwalkwaysandindividualautomatedguidedvehiclesystemswillcoverlongdis-tancesconvenientlyandquicklybetweendifferentterminalsandwithinlargeterminals.

Passengers will have information available at all times, providing a comprehensive choice of the modes of transport, prior to travel as well as in the case of rescheduling or unforeseen disruptions.

IntermodalityAmajorgoalforthefutureintermodaltransportsystemistoreducedependenceontheautomobileasthemajormodeofgroundtransportationandincrease use of public transport, especially in the case of the future air transport system.

Undergroundrailwaystationsbuiltbelowterminalsreducetheneedfor private cars as well as limiting the environmental footprint. Intermodality can be envisaged at several levels, from local publictransport to international connections:

• Citycentresandsuburbanareashavetobeaccessibleusing the tramway or subway connecting with railway stations located on the airport landside• Atregionallevel,connectionstoahigh-speedtrainisastrong advantageforanairport’sattractivenessifitisrapidandserves the nearby cities• Fornational/internationalconnections - Integration of airports within a regional/national railway networkorotherfuturemodesofpublictransport - Nationalrailwaystationsatairportsmustbepartofthelandside, wherethepassengerjourneystartswithpassengercheck-in and luggage deposit - High-speedtrainconnectionstoconnectregionalmegacities - Connectionsbetweenregionalairportstomajorhubswithhigh-speedtrainasanalternativetoshort-haulairservices,releasingslotsand relieving airport congestion

The airport landside should provide inter-terminal shuttles to provide convenient, fast and reliable services for the passenger and luggage. Automatic subway trains and/or tramways should be considered instead of buses.

Door-to-door journeyInthedoor-to-doorapproach,theairportlandsideisenlargedorredefined:

• Railwaystationsarepartofanextended‘landside’• Thejourneystartsanywhereinthepubliczone• Securitychecksandluggageregistration/depositaredoneintherailwaystation,onboardatrainorindedicatedpointsinacity• Quick&easycheckingusing,forexample,biometry• Luggagetransportationfromhometotheterminal/plane(ordoortodoor)isavailable• Thesubwayorrailroadservesalltheterminals/gates:longwalksarenolongerneededtoreachanypointintheairport(especiallywithundergroundterminals)

AIRPORT

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Airside-landside connection

Differentsystemswithintheairporthavetheirowninformationmanagementsystems,whichmustbecollectedandmanagedwithaholistic,centralizedapproach aimed at achieving a seamless flow of passengers and luggage.

Passenger Each category of passenger has their own requirements in terms of services, timing and dedicated spaces within the airport and possibly on the apron/aircraft.

Anadvancedsystemdevotedtosafety,security,dynamicriskmanagementandpassengers’satisfactioncouldcontain:

• Baggagetrackingandreconciliationforeachitemofbaggage• Extensionofbaggageidentificationtechniques• Applicationofmulti-scanningdevicesbasedoninnovative screening techniques for detecting dangerous materials• Automaticaircraftloadbalancingprocedures

The following technologies will be important:

• Localization• Voiceanddatalinkcommunications• Communicationsforhandlersanddrivers• Technologyfordetecting,locating,trackingandtracingpassengers, integratedwithticketinformation

BoardingLandsidesecuritycheckscanbeperformedbiometricallywhilethepassengerisintheairport.Thiswillrequire:• Optimisingthepositionofthesecuritychecks• Optimisinggateplanning• Allowingpassengerstochoosethewaytheyreachtheaircraft,dependingontheavailabilityoftime

Aircraft Automatedtrackingofequipmentandmaintenanceactivitieswillbebasedoninnovativetechniquesforfusinginformationfromdataprocessingsystemsandmonitoringdevices(high-resolutionradar,cameras,radio-communications,GPS/EGNOS).

Useofidentificationsystemsformonitoringandinterpretingtheactivitiesofapronvehiclesandoperationswillallowautomaticdetection,trackingandclassificationthroughdistributedsensorsandamanagementdatasystem.

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Technologies for the airport of 2050Thetablebelowsummarisesthetechnologiesandcompetencesofferedbytheaeronauticalresearchcentresthatwillmakemajorcontributionstotheairport of 2050.

AIRPORT

Passenger- Two-way communication devices: oriented -Datalinktechnologiesandwirelesscommunications Usercomfortairport -Cloudcomputing,computeridentification,human-machineinterfaces Capacity -Robotics:assistancerobots.Terminaltransportsystems

Datafusiontechniques,fieldsensornetwork Visiontechniques,remotesensorsandacquisitiondevicesforsecuritycheck SafetyOperations Information&Communicationtechnology,dynamicmulti-riskmanagement Security Newaircraftconfigurations Environment Newaircraftproceduresandnewproceduresmanagement Capacity

Information Optimisationanalysisbasedonmulti-actor,multi-objective,riskmonitoring,handling and management system, sensors and ambient intelligencecollaborative Near-fieldcommunicationtechnologies,RFID,Bluetoothandmobiledevices, Capacitydecision LEDbarcodes Safetymaking Developmentofmulti-scanningdevices Security Voiceanddatalinkbetweenbase-stationandvehicles, various transmission technologies GPS,Galileo,highresolutionradar

Ground-based Developnoise-preferentialapproachesnoise Noisemonitoringandmodelling Environmentmeasurements Noisewallsoranti-noiseinterferencessystems

All weather The aircraft as a meteorological sensor Capacityoperations Improvedinstantforecasting(i.eforstrongwinds) Safety Information sharing with other air vehicles and the ground

Airport componentand functions

Promising technologies drivers

Airp

ort N

etw

ork

Airs

ide

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Airquality Newtechnologiestoreducefuelconsumption(TO,taxiing,APU…) Environmentimprovement Develop air quality monitoring: numerical forecast at local scale and measurements

Capacity Improvementsofoperationsplanning(SESARandpost-SESAR) Capacity

Locationandsizeof Newrunwayconcepts:double-deckrunwaystoreducelanduse,Airportsinthesky Capacityrunways

Operational Highprecisionapproachsystemstoreduceseparation Capacityprocedures Safety

Reduced Wakevortexmonitoringandmodelling Capacityseparations Safety

Landingand Developnewconcepts:catapult,railsystem,tractorbeam,cables… Environment:take-offpower noiseand emissions reductions 4-DTrajectory Datanetworkabletosupport4Doperations(groundandair) CapacityOperationson Datalinkanddatatransmission Safetythe ground

Electrictaxiing Developelectricnosewheelpoweredbyafuelcellorelectricenergy Environment Useofspecialelectricpoweredvehicles(Taxibot,autonomousorcontrolledbytheaircraft) ElectricEnergy Developenergysourcesfromsolar(roofsofterminals),geothermal,windparks Environment (especiallyinoffshoreairports)

User-oriented Geo-localizationandwirelesstechnologies Usercomfortterminal Datalink Capacityconcept

Baggage Baggageidentificationtechniques:radiofrequencies(RFID),chip Usercomforthandling Securityscreeningtechniques(fast,secure,reliable) Capacity Automatic aircraft loading calculations Security

Airport componentand functions

Promising technologies drivers

Airs

ide

Ru

nway

sCo

nnec

tion

Airs

ide

Land

side

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Boarding Multi-biometricaltechniques Usercomfortmechanism Capacity

Aircraft Data fusion from heterogeneous sources Securityprocess Multi-cameravisualsurveillancesystemsforgroundmovementsmonitoring Capacity

Newconfigurations(BlendedWingBodyaircraft) SecurityCargo Goodstracking:RFID Capacity Capable security screening technologies

Energyefficient Developpassivebuildingsforterminals,renewableenergyfacility Buildingsadaptedtorealweatherconditions? Environmentmanagement Decrease Automation of terminal processespassengertime Wirelesstechnologies Usercomfortconsuming Data fusion covering whole travel chain Datalinktechnologies

Non-intrusive Remotesensingimaging(scanner) SecuritySecurity Securityscreeningtechniquesofpersonsand(hand-)baggage(fast,secure,reliable) Usercomfort

Door to Door Data bases management Securitytravel Biometriccontrols Usercomfort

Intelligent& Wirelesstechnologies,GPSetc. EnvironmentInteractive Networkofsensor&Datafusion Securityticket Datalinktechnologies Usercomfort

AIRPORT

Airport componentand functions

Promising technologies drivers

Land

side

Inte

rmod

al

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ACRONYMS

ACARE advisorycouncilforaeronauticalresearchinEurope

ATAG airtransportactiongroup

ATC airtrafficcontrol

ATM airtrafficmanagement

ATS airtransportsystem/airtrafficservices

APU auxiliarypowerunit

BWB blendedwingbody

CAEP committee on aviation environmental protection

CFD computational fluid dynamics

CFRP carbonfibrereinforcedplastic

CO2 carbondioxide

DNS directnumericalsimulation

EC European commission

ECAM electroniccentralisedaircraftmonitor

EGNOS Europeangeostationarynavigationoverlayservice

EPNdB effectiveperceivednoiselevelindecibels

EREA associationofEuropeanresearchestablishmentsinaeronautics

EM electromagnetic

EVS enhanced vision system

FMS flightmanagementsystem

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GPS globalpositioningsystem

GNSS globalnavigationsatellitesystem

GLONASS RussianGNSS

HALE highaltitudelongendurance

HMI humanmachineinterface

HUD head-updisplay

ICAO internationalcivilaviationorganisation

ICT information and communications technology

LED lightemittingdiode

RFID radiofrequencyidentification

LIDAR lightdetectionandranging

MEMS microelectromechanicalsystems

NOX nitrogenoxides

PEM protonexchangemembrane

SAR syntheticapertureradar

SESAR singleEuropeanskyATMresearch

SUGAR subsonicultra-greenaircraftresearch

UAV unmannedaerialvehicle

WiMAX worldwideinteroperabilityformicrowaveaccess

WLAN wirelesslocalareanetwork

Editorial coordinationPhilippe Benhamou

ONERADépartementProspectiveAérospatiale

EditorJulian Moxon

Graphics and illustrationYannick Chosse – Poussière de Pixel

DesignAgence de communication – DifferenCie

PrintingK’ Design Impression

Publisherthe Association of European Research Establishments in Aeronautics

www.erea.org

May 2012