AirportTrafficControlToweratBordeauxMrignacAirportAirportTrafficControlTower(ATCT)atSuvarnabhumiAirport,Thailand.AirtrafficcontrolFromWikipedia,thefreeencyclopediaAirtrafficcontrol(ATC)isaserviceprovidedbygroundbasedcontrollerswhodirectaircraftonthegroundandthroughcontrolledairspace,andcanprovideadvisoryservicestoaircraftinnoncontrolledairspace.TheprimarypurposeofATCworldwideistopreventcollisions,organizeandexpeditetheflowoftraffic,andprovideinformationandothersupportforpilots.[1]Insomecountries,ATCplaysasecurityordefensiverole,orisoperatedbythemilitary.Topreventcollisions,ATCenforcestrafficseparationrules,whichensureeachaircraftmaintainsaminimumamountofemptyspacearounditatalltimes.Manyaircraftalsohavecollisionavoidancesystems,whichprovideadditionalsafetybywarningpilotswhenotheraircraftgettooclose.Inmanycountries,ATCprovidesservicestoallprivate,military,andcommercialaircraftoperatingwithinitsairspace.Dependingonthetypeofflightandtheclassofairspace,ATCmayissueinstructionsthatpilotsarerequiredtoobey,oradvisories(knownasflightinformationinsomecountries)thatpilotsmay,attheirdiscretion,disregard.Thepilotincommandisthefinalauthorityforthesafeoperationoftheaircraftandmay,inanemergency,deviatefromATCinstructionstotheextentrequiredtomaintainsafeoperationoftheiraircraft.Contents1Language2History3Airportcontrol3.1Groundcontrol3.2Localcontroloraircontrol3.3Flightdata/clearancedelivery3.4Approachandterminalcontrol4Enroute,center,orareacontrol4.1Generalcharacteristics4.2Radarcoverage4.3Flighttrafficmapping5Problems5.1Traffic5.2Weather6Callsigns7Technology8Airnavigationserviceproviders(ANSPs)andairtrafficAirportTrafficControlTower1(ATCT1)atKualaLumpurInternationalAirport,Malaysia.8Airnavigationserviceproviders(ANSPs)andairtrafficserviceproviders(ATSPs)9Proposedchanges10ATCregulationsintheUnitedStates11Seealso12References13ExternallinksLanguagePursuanttorequirementsoftheInternationalCivilAviationOrganization(ICAO),ATCoperationsareconductedeitherintheEnglishlanguageorthelanguageusedbythestationontheground.[2]Inpractice,thenativelanguageforaregionisnormallyusedhowever,theEnglishlanguagemustbeuseduponrequest.[2]HistoryIn1921,CroydonAirport,Londonwasthefirstairportintheworldtointroduceairtrafficcontrol.[3]InAmerica,AirTrafficControldevelopedthreedivisions.ThefirstAirMailRadioStations(AMRS)wascreatedin1922afterWorldWar1whentheUSPostOfficebeganusingtechniquesdevelopedbytheArmytodirectandtrackthemovementsofreconnaissanceaircraft.OvertimetheAMRSmorphedintoFlightServiceStations.Today'sFlightServiceStationsdonotissuecontrolinstructions,butprovidepilotswithmanyotherflightrelatedinformationalservices.TheydorelaycontrolinstructionsfromATCinareaswhereFlightServiceistheonlyfacilitywithradioorphonecoverage.ThefirstAirportTrafficControlTower,regulatingarrivals,departuresandsurfacemovementofaircraftataspecificairport,openedinClevelandin1930.Approach/DepartureControlfacilitieswerecreatedafteradoptionofRADARinthe1950stomonitorandcontrolthebusyairspacearoundlargerairports.ThefirstAirRouteTrafficControlCenter,whichdirectsthemovementofaircraftbetweendepartureanddestinationwasopenedinNewark,NJin1935,followedin1936byChicagoandCleveland.[4]AirportcontrolTheprimarymethodofcontrollingtheimmediateairportenvironmentisvisualobservationfromtheairportcontroltower(TWR).Thetowerisatall,windowedstructurelocatedontheairportgrounds.Airtrafficcontrollersareresponsiblefortheseparationandefficientmovementofaircraftandvehiclesoperatingonthetaxiwaysandrunwaysoftheairportitself,andaircraftintheairneartheairport,generally5to10nauticalmiles(9to18km)dependingontheairportprocedures.AirportTrafficControlTower2(ATCT2)atKualaLumpurInternationalAirport,Malaysia.Surveillancedisplaysarealsoavailabletocontrollersatlargerairportstoassistwithcontrollingairtraffic.Controllersmayusearadarsystemcalledsecondarysurveillanceradarforairbornetrafficapproachinganddeparting.Thesedisplaysincludeamapofthearea,thepositionofvariousaircraft,anddatatagsthatincludeaircraftidentification,speed,altitude,andotherinformationdescribedinlocalprocedures.Inadverseweatherconditionsthetowercontrollersmayalsousesurfacemovementradar(SMR),surfacemovementguidanceandcontrolsystems(SMGCS)oradvancedSMGCStocontroltrafficonthemanoeuvringarea(taxiwaysandrunway).TheareasofresponsibilityforTWRcontrollersfallintothreegeneraloperationaldisciplinesLocalControlorAirControl,GroundControl,andFlightData/ClearanceDeliveryothercategories,suchasApronControlorGroundMovementPlanner,mayexistatextremelybusyairports.WhileeachTWRmayhaveuniqueairportspecificprocedures,suchasmultipleteamsofcontrollers('crews')atmajororcomplexairportswithmultiplerunways,thefollowingprovidesageneralconceptofthedelegationofresponsibilitieswithintheTWRenvironment.RemoteandVirtualTower(RVT)isasystembasedonAirTrafficControllersbeinglocatedsomewhereotherthanatthelocalairporttowerandstillabletoprovideAirTrafficControlservices.DisplaysfortheAirTrafficControllersmaybeeitheropticallivevideoand/orsyntheticimagesbasedonsurveillancesensordata.GroundcontrolGroundControl(sometimesknownasGroundMovementControl)isresponsiblefortheairport"movement"areas,aswellasareasnotreleasedtotheairlinesorotherusers.Thisgenerallyincludesalltaxiways,inactiverunways,holdingareas,andsometransitionalapronsorintersectionswhereaircraftarrive,havingvacatedtherunwayordeparturegate.Exactareasandcontrolresponsibilitiesareclearlydefinedinlocaldocumentsandagreementsateachairport.Anyaircraft,vehicle,orpersonwalkingorworkingintheseareasisrequiredtohaveclearancefromGroundControl.ThisisnormallydoneviaVHF/UHFradio,buttheremaybespecialcaseswhereotherproceduresareused.AircraftorvehicleswithoutradiosmustrespondtoATCinstructionsviaaviationlightsignalsorelsebeledbyvehicleswithradios.PeopleworkingontheairportsurfacenormallyhaveacommunicationslinkthroughwhichtheycancommunicatewithGroundControl,commonlyeitherbyhandheldradioorevencellphone.GroundControlisvitaltothesmoothoperationoftheairport,becausethispositionimpactsthesequencingofdepartureaircraft,affectingthesafetyandefficiencyoftheairport'soperation.SomebusierairportshaveSurfaceMovementRadar(SMR),suchas,ASDE3,AMASSorASDEX,designedtodisplayaircraftandvehiclesontheground.TheseareusedbyGroundControlasanadditionaltooltocontrolgroundtraffic,particularlyatnightorinpoorvisibility.Thereareawiderangeofcapabilitiesonthesesystemsastheyarebeingmodernized.Oldersystemswilldisplayamapoftheairportandthetarget.Newersystemsincludethecapabilitytodisplayhigherqualitymapping,radartarget,datablocks,andsafetyalerts,andtointerfacewithothersystemssuchasdigitalflightstrips.TrafficControlToweratOsloGardermoenAirport,NorwayLocalcontroloraircontrolLocalControl(knowntopilotsas"Tower"or"TowerControl")isresponsiblefortheactiverunwaysurfaces.LocalControlclearsaircraftfortakeofforlanding,ensuringthatprescribedrunwayseparationwillexistatalltimes.IfLocalControldetectsanyunsafecondition,alandingaircraftmaybetoldto"goaround"andberesequencedintothelandingpatternbytheapproachorterminalareacontroller.WithintheTWR,ahighlydisciplinedcommunicationsprocessbetweenLocalControlandGroundControlisanabsolutenecessity.GroundControlmustrequestandgainapprovalfromLocalControltocrossanyactiverunwaywithanyaircraftorvehicle.Likewise,LocalControlmustensurethatGroundControlisawareofanyoperationsthatwillimpactthetaxiways,andworkwiththeapproachradarcontrollerstocreate"holes"or"gaps"inthearrivaltraffictoallowtaxiingtraffictocrossrunwaysandtoallowdepartingaircrafttotakeoff.CrewResourceManagement(CRM)proceduresareoftenusedtoensurethiscommunicationprocessisefficientandclear,althoughthisisnotasprevalentasCRMforpilots.Flightdata/clearancedeliveryClearanceDeliveryisthepositionthatissuesrouteclearancestoaircraft,typicallybeforetheycommencetaxiing.Thesecontaindetailsoftheroutethattheaircraftisexpectedtoflyafterdeparture.ClearanceDeliveryor,atbusyairports,theTrafficManagementCoordinator(TMC)will,ifnecessary,coordinatewiththeenroutecenterandnationalcommandcenterorflowcontroltoobtainreleasesforaircraft.Often,however,suchreleasesaregivenautomaticallyorarecontrolledbylocalagreementsallowing"freeflow"departures.Whenweatherorextremelyhighdemandforacertainairportorairspacebecomesafactor,theremaybeground"stops"(or"slotdelays")orreroutesmaybenecessarytoensurethesystemdoesnotgetoverloaded.TheprimaryresponsibilityofClearanceDeliveryistoensurethattheaircrafthavetheproperrouteandslottime.ThisinformationisalsocoordinatedwiththeenroutecenterandGroundControlinordertoensurethattheaircraftreachestherunwayintimetomeettheslottimeprovidedbythecommandcenter.Atsomeairports,ClearanceDeliveryalsoplansaircraftpushbacksandenginestarts,inwhichcaseitisknownastheGroundMovementPlanner(GMP):thispositionisparticularlyimportantatheavilycongestedairportstopreventtaxiwayandaprongridlock.FlightData(whichisroutinelycombinedwithClearanceDelivery)isthepositionthatisresponsibleforensuringthatbothcontrollersandpilotshavethemostcurrentinformation:pertinentweatherchanges,outages,airportgrounddelays/groundstops,runwayclosures,etc.FlightDatamayinformthepilotsusingarecordedcontinuouslooponaspecificfrequencyknownastheAutomaticTerminalInformationService(ATIS).ApproachandterminalcontrolAirportTrafficControlToweratJuandaInternationalAirport,IndonesiaManyairportshavearadarcontrolfacilitythatisassociatedwiththeairport.Inmostcountries,thisisreferredtoasTerminalControlintheU.S.,itisreferredtoasaTRACON(TerminalRadarApproachControl).Whileeveryairportvaries,terminalcontrollersusuallyhandletrafficina30to50nauticalmile(56to93km)radiusfromtheairport.Wheretherearemanybusyairportsclosetogether,oneconsolidatedTerminalControlCentermayservicealltheairports.TheairspaceboundariesandaltitudesassignedtoaTerminalControlCenter,whichvarywidelyfromairporttoairport,arebasedonfactorssuchastrafficflows,neighboringairportsandterrain.AlargeandcomplexexampleistheLondonTerminalControlCentrewhichcontrolstrafficforfivemainLondonairportsupto20,000feet(6,100m)andoutto100nauticalmiles(190km).TerminalcontrollersareresponsibleforprovidingallATCserviceswithintheirairspace.Trafficflowisbroadlydividedintodepartures,arrivals,andoverflights.Asaircraftmoveinandoutoftheterminalairspace,theyarehandedofftothenextappropriatecontrolfacility(acontroltower,anenroutecontrolfacility,oraborderingterminalorapproachcontrol).Terminalcontrolisresponsibleforensuringthataircraftareatanappropriatealtitudewhentheyarehandedoff,andthataircraftarriveatasuitablerateforlanding.Notallairportshavearadarapproachorterminalcontrolavailable.Inthiscase,theenroutecenteroraneighboringterminalorapproachcontrolmaycoordinatedirectlywiththetowerontheairportandvectorinboundaircrafttoapositionfromwheretheycanlandvisually.Atsomeoftheseairports,thetowermayprovideanonradarproceduralapproachservicetoarrivingaircrafthandedoverfromaradarunitbeforetheyarevisualtoland.Someunitsalsohaveadedicatedapproachunitwhichcanprovidetheproceduralapproachserviceeitherallthetimeorforanyperiodsofradaroutageforanyreason.IntheU.S.,TRACONsareadditionallydesignatedbyathreeletteralphanumericcode.Forexample,theChicagoTRACONisdesignatedC90.[5]Enroute,center,orareacontrolATCprovidesservicestoaircraftinflightbetweenairportsaswell.Pilotsflyunderoneoftwosetsofrulesforseparation:VisualFlightRules(VFR)orInstrumentFlightRules(IFR).Airtrafficcontrollershavedifferentresponsibilitiestoaircraftoperatingunderthedifferentsetsofrules.WhileIFRflightsareunderpositivecontrol,intheUSVFRpilotscanrequestflightfollowing,whichprovidestrafficadvisoryservicesonatimepermittingbasisandmayalsoprovideassistanceinavoidingareasofweatherandflightrestrictions.AcrossEurope,pilotsmayrequestfora"FlightInformationService",whichissimilartoflightfollowing.IntheUKitisknownasa"TrafficService".Enrouteairtrafficcontrollersissueclearancesandinstructionsforairborneaircraft,andpilotsarerequiredtocomplywiththeseinstructions.Enroutecontrollersalsoprovideairtrafficcontrolservicestomanysmallerairportsaroundthecountry,includingclearanceoffofthegroundandclearanceforapproachtoanNewLaGuardiaAirport(LGA)ControlTowerinNewYorkCity.ControlTowerBrusselsAirportairport.Controllersadheretoasetofseparationstandardsthatdefinetheminimumdistanceallowedbetweenaircraft.ThesedistancesvarydependingontheequipmentandproceduresusedinprovidingATCservices.GeneralcharacteristicsEnrouteairtrafficcontrollersworkinfacilitiescalledAirTrafficControlCenters,eachofwhichiscommonlyreferredtoasa"Center".TheUnitedStatesusestheequivalenttermAirRouteTrafficControlCenter(ARTCC).Eachcenterisresponsibleformanythousandsofsquaremilesofairspace(knownasaFlightInformationRegion)andfortheairportswithinthatairspace.CenterscontrolIFRaircraftfromthetimetheydepartfromanairportorterminalarea'sairspacetothetimetheyarriveatanotherairportorterminalarea'sairspace.Centersmayalso"pickup"VFRaircraftthatarealreadyairborneandintegratethemintotheIFRsystem.Theseaircraftmust,however,remainVFRuntiltheCenterprovidesaclearance.Centercontrollersareresponsibleforissuinginstructionstopilotstoclimbtheiraircrafttotheirassignedaltitudewhile,atthesametime,ensuringthattheaircraftisproperlyseparatedfromallotheraircraftintheimmediatearea.Additionally,theaircraftmustbeplacedinaflowconsistentwiththeaircraft'srouteofflight.Thiseffortiscomplicatedbycrossingtraffic,severeweather,specialmissionsthatrequirelargeairspaceallocations,andtrafficdensity.Whentheaircraftapproachesitsdestination,thecenterisresponsibleforissuinginstructionstopilotssothattheywillmeetaltituderestrictionsbyspecificpoints,aswellasprovidingmanydestinationairportswithatrafficflow,whichprohibitsallofthearrivalsbeing"bunchedtogether".These"flowrestrictions"oftenbegininthemiddleoftheroute,ascontrollerswillpositionaircraftlandinginthesamedestinationsothatwhentheaircraftareclosetotheirdestinationtheyaresequenced.AsanaircraftreachestheboundaryofaCenter'scontrolareaitis"handedoff"or"handedover"tothenextAreaControlCenter.Insomecasesthis"handoff"processinvolvesatransferofidentificationanddetailsbetweencontrollerssothatairtrafficcontrolservicescanbeprovidedinaseamlessmannerinothercaseslocalagreementsmayallow"silenthandovers"suchthatthereceivingcenterdoesnotrequireanycoordinationiftrafficispresentedinanagreedmanner.Afterthehandoff,theaircraftisgivenafrequencychangeandbeginstalkingtothenextcontroller.Thisprocesscontinuesuntiltheaircraftishandedofftoaterminalcontroller("approach").RadarcoverageChhatrapatiShivajiInternationalAirportControlTowerinMumbai,India.InsidetheSoPauloGuarulhosInternationalAirport'stower.Sincecenterscontrolalargeairspacearea,theywilltypicallyuselongrangeradarthathasthecapability,athigheraltitudes,toseeaircraftwithin200nauticalmiles(370km)oftheradarantenna.TheymayalsouseTRACONradardatatocontrolwhenitprovidesabetter"picture"ofthetrafficorwhenitcanfillinaportionoftheareanotcoveredbythelongrangeradar.IntheU.S.system,athigheraltitudes,over90%oftheU.S.airspaceiscoveredbyradarandoftenbymultipleradarsystemshowever,coveragemaybeinconsistentatloweraltitudesusedbyunpressurizedaircraftduetohighterrainordistancefromradarfacilities.Acentermayrequirenumerousradarsystemstocovertheairspaceassignedtothem,andmayalsorelyonpilotpositionreportsfromaircraftflyingbelowthefloorofradarcoverage.Thisresultsinalargeamountofdatabeingavailabletothecontroller.Toaddressthis,automationsystemshavebeendesignedthatconsolidatetheradardataforthecontroller.Thisconsolidationincludeseliminatingduplicateradarreturns,ensuringthebestradarforeachgeographicalareaisprovidingthedata,anddisplayingthedatainaneffectiveformat.Centersalsoexercisecontrolovertraffictravellingovertheworld'soceanareas.TheseareasarealsoFIRs.Becausetherearenoradarsystemsavailableforoceaniccontrol,oceaniccontrollersprovideATCservicesusingproceduralcontrol.Theseproceduresuseaircraftpositionreports,time,altitude,distance,andspeedtoensureseparation.Controllersrecordinformationonflightprogressstripsandinspeciallydevelopedoceaniccomputersystemsasaircraftreportpositions.Thisprocessrequiresthataircraftbeseparatedbygreaterdistances,whichreducestheoverallcapacityforanygivenroute.SeeforexampletheNorthAtlanticTracksystem.SomeAirNavigationServiceProviders(e.g.AirservicesAustralia,TheFederalAviationAdministration,NAVCANADA,etc.)haveimplementedautomaticdependentsurveillancebroadcast(ADSB)aspartoftheirsurveillancecapability.Thisnewtechnologyreversestheradarconcept.Insteadofradar"finding"atargetbyinterrogatingthetransponder,theADSequippedaircraftsendsapositionreportasdeterminedbythenavigationequipmentonboardtheaircraft.Normally,ADSoperatesinthe"contract"modewheretheaircraftreportsaposition,automaticallyorinitiatedbythepilot,basedonapredeterminedtimeinterval.Itisalsopossibleforcontrollerstorequestmorefrequentreportstomorequicklyestablishaircraftpositionforspecificreasons.However,sincethecostforeachreportischargedbytheADSserviceproviderstothecompanyoperatingtheaircraft,morefrequentreportsarenotcommonlyrequestedexceptinemergencysituations.ADSissignificantbecauseitcanbeusedwhereitisnotpossibletolocatetheinfrastructureforaradarsystem(e.g.overwater).ComputerizedradardisplaysarenowbeingdesignedtoacceptADSinputsaspartofthedisplay.ThistechnologyiscurrentlyusedinportionsoftheNorthAtlanticandthePacificbyavarietyofstateswhoshareresponsibilityforthecontrolofthisairspace.PotomacConsolidatedTRACONinWarrenton,Virginia,UnitedStates.ThetrainingdepartmentattheWashingtonAirRouteTrafficControlCenter,Leesburg,Virginia,UnitedStates.Precisionapproachradarsarecommonlyusedbymilitarycontrollersofairforcesofseveralcountries,toassistthePilotinfinalphasesoflandinginplaceswhereInstrumentLandingSystemandothersophisticatedairborneequipmentareunavailabletoassistthepilotsinmarginalornearzerovisibilityconditions.ThisprocedureisalsocalledTalkdowns.ARadarArchiveSystem(RAS)keepsanelectronicrecordofallradarinformation,preservingitforafewweeks.Thisinformationcanbeusefulforsearchandrescue.Whenanaircrafthas'disappeared'fromradarscreens,acontrollercanreviewthelastradarreturnsfromtheaircrafttodetermineitslikelyposition.Forexample,seethiscrashreport.[6]RASisalsousefultotechnicianswhoaremaintainingradarsystems.FlighttrafficmappingThemappingofflightsinrealtimeisbasedontheairtrafficcontrolsystem.In1991,dataonthelocationofaircraftwasmadeavailablebytheFederalAviationAdministrationtotheairlineindustry.TheNationalBusinessAviationAssociation(NBAA),theGeneralAviationManufacturersAssociation,theAircraftOwners&PilotsAssociation,theHelicopterAssociationInternational,andtheNationalAirTransportationAssociationpetitionedtheFAAtomakeASDIinformationavailableona"needtoknow"basis.Subsequently,NBAAadvocatedthebroadscaledisseminationofairtrafficdata.TheAircraftSituationalDisplaytoIndustry(ASDI)systemnowconveysuptodateflightinformationtotheairlineindustryandthepublic.SomecompaniesthatdistributeASDIinformationareFlightExplorer,FlightView,andFlyteComm.Eachcompanymaintainsawebsitethatprovidesfreeupdatedinformationtothepubliconflightstatus.StandaloneprogramsarealsoavailablefordisplayingthegeographiclocationofairborneIFR(InstrumentFlightRules)airtrafficanywhereintheFAAairtrafficsystem.Positionsarereportedforbothcommercialandgeneralaviationtraffic.Theprogramscanoverlayairtrafficwithawideselectionofmapssuchas,geopoliticalboundaries,airtrafficcontrolcenterboundaries,highaltitudejetroutes,satellitecloudandradarimagery.ProblemsTrafficFormoreinformationseeAirtrafficflowmanagement.Thedaytodayproblemsfacedbytheairtrafficcontrolsystemareprimarilyrelatedtothevolumeofairtrafficdemandplacedonthesystemandweather.Severalfactorsdictatetheamountoftrafficthatcanlandatanairportinagivenamountoftime.Eachlandingaircraftmusttouchdown,slow,andexittherunwaybeforethenextcrossestheapproachendoftherunway.Thisprocessrequiresatleastoneanduptofourminutesforeachaircraft.Allowingfordeparturesbetweenarrivals,eachrunwaycanthushandleabout30IntersectingcontrailsofaircraftoverLondon,anareaofhighairtraffic.arrivalsperhour.Alargeairportwithtwoarrivalrunwayscanhandleabout60arrivalsperhouringoodweather.Problemsbeginwhenairlinesschedulemorearrivalsintoanairportthancanbephysicallyhandled,orwhendelayselsewherecausegroupsofaircraftthatwouldotherwisebeseparatedintimetoarrivesimultaneously.Aircraftmustthenbedelayedintheairbyholdingoverspecifiedlocationsuntiltheymaybesafelysequencedtotherunway.Upuntilthe1990s,holding,whichhassignificantenvironmentalandcostimplications,wasaroutineoccurrenceatmanyairports.Advancesincomputersnowallowthesequencingofplaneshoursinadvance.Thus,planesmaybedelayedbeforetheyeventakeoff(bybeinggivena"slot"),ormayreducespeedinflightandproceedmoreslowlythussignificantlyreducingtheamountofholding.Airtrafficcontrolerrorsoccurwhentheseparation(eitherverticalorhorizontal)betweenairborneaircraftfallsbelowtheminimumprescribedseparationset(forthedomesticUnitedStates)bytheUSFederalAviationAdministration.Separationminimumsforterminalcontrolareas(TCAs)aroundairportsarelowerthanenroutestandards.Errorsgenerallyoccurduringperiodsfollowingtimesofintenseactivity,whencontrollerstendtorelaxandoverlookthepresenceoftrafficandconditionsthatleadtolossofminimumseparation.[7]Paradoxically,currenthighprecisioncruisingaltituderulesincreasetheriskofcollisionbetween10and33timesovermoresloppyalternativeswhenairtrafficcontrolerrorsoccur.WeatherBeyondrunwaycapacityissues,weatherisamajorfactorintrafficcapacity.Rain,iceorsnowontherunwaycauselandingaircrafttotakelongertoslowandexit,thusreducingthesafearrivalrateandrequiringmorespacebetweenlandingaircraft.Fogalsorequiresadecreaseinthelandingrate.These,inturn,increaseairbornedelayforholdingaircraft.Ifmoreaircraftarescheduledthancanbesafelyandefficientlyheldintheair,agrounddelayprogrammaybeestablished,delayingaircraftonthegroundbeforedepartureduetoconditionsatthearrivalairport.InAreaControlCenters,amajorweatherproblemisthunderstorms,whichpresentavarietyofhazardstoaircraft.Aircraftwilldeviatearoundstorms,reducingthecapacityoftheenroutesystembyrequiringmorespaceperaircraft,orcausingcongestionasmanyaircrafttrytomovethroughasingleholeinalineofthunderstorms.Occasionallyweatherconsiderationscausedelaystoaircraftpriortotheirdepartureasroutesareclosedbythunderstorms.Muchmoneyhasbeenspentoncreatingsoftwaretostreamlinethisprocess.However,atsomeACCs,airtrafficcontrollersstillrecorddataforeachflightonstripsofpaperandpersonallycoordinatetheirpaths.Innewersites,theseflightprogressstripshavebeenreplacedbyelectronicdatapresentedoncomputerscreens.Asnewequipmentisbroughtin,moreandmoresitesareupgradingawayfrompaperflightstrips.CallsignsAprerequisitetosafeairtrafficseparationistheassignmentanduseofdistinctivecallsigns.ThesearepermanentlyallocatedbyICAOonrequestusuallytoscheduledflightsandsomeairforcesformilitaryflights.Theyarewrittencallsignswith3lettercombinationlikeKLM,BAW,VLGfollowedbytheflightnumber,likeAAL872,VLG1011.AssuchtheyappearonflightplansandATCradarlabels.TherearealsotheaudioorRadiotelephonycallsignsusedontheradiocontactbetweenpilotsandAirTrafficControl.Thesearenotalwaysidenticaltotheirwrittencounterparts.Anexampleofanaudiocallsignwouldbe"Speedbird832",insteadofthewritten"BAW832".ThisisusedtoreducethechanceofconfusionbetweenATCandtheaircraft.Bydefault,thecallsignforanyotherflightistheregistrationnumber(tailnumber)oftheaircraft,suchas"N12345","CGABC"or"ECIZD".TheshortRadiotelephonycallsignsforthesetailnumbersisthelast3lettersusingtheNATOphoneticalphabet(i.e.ABCspokenAlphaBravoCharlie)forCGABCorthelast3numberslike345spokenasTREEFOREFIFEforN12345.IntheUnitedStates,theprefixmaybeanaircrafttype,modelormanufacturerinplaceofthefirstregistrationcharacter,forexample"N11842"couldbecome"Cessna842".[8]Thisabbreviationisonlyallowedaftercommunicationshasbeenestablishedineachsector.Theflightnumberpartisdecidedbytheaircraftoperator.Inthisarrangement,anidenticalcallsignmightwellbeusedforthesamescheduledjourneyeachdayitisoperated,evenifthedeparturetimevariesalittleacrossdifferentdaysoftheweek.Thecallsignofthereturnflightoftendiffersonlybythefinaldigitfromtheoutboundflight.Generally,airlineflightnumbersareevenifeastbound,andoddifwestbound.Inordertoreducethepossibilityoftwocallsignsononefrequencyatanytimesoundingtoosimilar,anumberofairlines,particularlyinEurope,havestartedusingalphanumericcallsignsthatarenotbasedonflightnumbers.Forexample,DLH23LG,spokenaslufthansatwothreelimagolf.Additionallyitistherightoftheairtrafficcontrollertochangethe'audio'callsignfortheperiodtheflightisinhissectorifthereisariskofconfusion,usuallychoosingthetailnumberinstead.Beforearound1980InternationalAirTransportAssociation(IATA)andICAOwereusingthesame2lettercallsigns.DuetothelargernumberofnewairlinesafterderegulationICAOestablishedthe3lettercallsignsasmentionedabove.TheIATAcallsignsarecurrentlyusedinaerodromesontheannouncementtablesbutneverusedanylongerinAirTrafficControl.Forexample,AAistheIATAcallsignforAmericanAirlinesATCequivalentAAL.OtherexamplesincludeLY/ELYforElAl,DL/DALforDeltaAirLines,VY/VLGforVuelingAirlines,etc.TechnologyManytechnologiesareusedinairtrafficcontrolsystems.Primaryandsecondaryradarareusedtoenhanceacontroller'ssituationawarenesswithinhisassignedairspacealltypesofaircraftsendbackprimaryechoesofvaryingsizestocontrollers'screensasradarenergyisbouncedofftheirskins,andtransponderequippedaircraftreplytosecondaryradarinterrogationsbygivinganID(ModeA),analtitude(ModeC)and/orauniquecallsign(ModeS).Certaintypesofweathermayalsoregisterontheradarscreen.Theseinputs,addedtodatafromotherradars,arecorrelatedtobuildtheairsituation.Somebasicprocessingoccursontheradartracks,suchascalculatinggroundspeedandmagneticheadings.Usually,aFlightDataProcessingSystemmanagesalltheflightplanrelateddata,incorporatinginaloworhighdegreetheinformationofthetrackoncethecorrelationbetweenthem(flightplanandtrack)isestablished.Allthisinformationisdistributedtomodernoperationaldisplaysystems,makingitavailabletocontrollers.TheFAAhasspentoverUS$3billiononsoftware,butafullyautomatedsystemisstilloverthehorizon.In2002theUKbroughtanewareacontrolcentreintoserviceattheLondonAreaControlCentre,Swanwick,Hampshire,relievingabusysuburbancentreatWestDrayton,Middlesex,northofLondonHeathrowTheairtrafficcontroltoweratHartsfieldJacksonAtlantaInternationalAirport,thebusiestairportintheworld.Airport.SoftwarefromLockheedMartinpredominatesattheLondonAreaControlCentre.However,thecentrewasinitiallytroubledbysoftwareandcommunicationsproblemscausingdelaysandoccasionalshutdowns.[9]Sometoolsareavailableindifferentdomainstohelpthecontrollerfurther:FlightDataProcessingSystems:thisisthesystem(usuallyoneperCenter)thatprocessesalltheinformationrelatedtotheFlight(theFlightPlan),typicallyinthetimehorizonfromGatetogate(airportdeparture/arrivalgates).ItusessuchprocessedinformationtoinvokeotherFlightPlanrelatedtools(suchase.g.MTCD),anddistributessuchprocessedinformationtoallthestakeholders(AirTrafficControllers,collateralCenters,Airports,etc.).ShortTermConflictAlert(STCA)thatcheckspossibleconflictingtrajectoriesinatimehorizonofabout2or3minutes(orevenlessinapproachcontext35secondsintheFrenchRoissy&Orlyapproachcentres[10])andalertsthecontrollerpriortothelossofseparation.Thealgorithmsusedmayalsoprovideinsomesystemsapossiblevectoringsolution,thatis,themannerinwhichtoturn,descend,orclimbtheaircraftinordertoavoidinfringingtheminimumsafetydistanceoraltitudeclearance.MinimumSafeAltitudeWarning(MSAW):atoolthatalertsthecontrollerifanaircraftappearstobeflyingtoolowtothegroundorwillimpactterrainbasedonitscurrentaltitudeandheading.SystemCoordination(SYSCO)toenablecontrollertonegotiatethereleaseofflightsfromonesectortoanother.AreaPenetrationWarning(APW)toinformacontrollerthataflightwillpenetratearestrictedarea.ArrivalandDepartureManagertohelpsequencethetakeoffandlandingofaircraft.TheDepartureManager(DMAN):AsystemaidfortheATCatairports,thatcalculatesaplanneddepartureflowwiththegoaltomaintainanoptimalthroughputattherunway,reducequeuingatholdingpointanddistributetheinformationtovariousstakeholdersattheairport(i.e.theairline,groundhandlingandAirTrafficControl(ATC)).TheArrivalManager(AMAN):AsystemaidfortheATCatairports,thatcalculatesaplannedArrivalflowwiththegoaltomaintainanoptimalthroughputattherunway,reducearrivalqueuinganddistributetheinformationtovariousstakeholders.passiveFinalApproachSpacingTool(pFAST),aCTAStool,providesrunwayassignmentandsequencenumberadvisoriestoterminalcontrollerstoimprovethearrivalrateatcongestedairports.pFASTwasdeployedandoperationalatfiveUSTRACONsbeforebeingcancelled.NASAresearchincludedanActiveFASTcapabilitythatalsoprovidedvectorandspeedadvisoriestoimplementtherunwayandsequenceadvisories.ConvergingRunwayDisplayAid(CRDA)enablesApproachcontrollerstoruntwofinalapproachesthatintersectandmakesurethatgoaroundsareminimizedCenterTRACONAutomationSystem(CTAS)isasuiteofhumancentereddecisionsupporttoolsdevelopedbyNASAAmesResearchCenter.SeveraloftheCTAStoolshavebeenfieldtestedandtransitionedtotheFAAforoperationalevaluationanduse.SomeoftheCTAStoolsare:TrafficManagementAdvisor(TMA),passiveFinalApproachSpacingTool(pFAST),CollaborativeArrivalPlanning(CAP),DirectTo(D2),EnRouteDescentAdvisor(EDA)andMultiCenterTMA.ThesoftwareisrunningonLinux.[11]TrafficManagementAdvisor(TMA),aCTAStool,isanenroutedecisionsupporttoolthatautomatestimebasedmeteringsolutionstoprovideanupperlimitofaircrafttoaTRACONfromtheCenteroverasetperiodoftime.Schedulesaredeterminedthatwillnotexceedthespecifiedarrivalrateandcontrollersusethescheduledtimestoprovidetheappropriatedelaytoarrivalswhileintheenroutedomain.Thisresultsinanoverallreductioninenroutedelaysandalsomovesthedelaystomoreefficientairspace(higheraltitudes)thanoccurifholdingneartheTRACONboundaryisrequiredtonotoverloadtheTRACONcontrollers.TMAisoperationalatmostenrouteairroutetrafficcontrolcenters(ARTCCs)andcontinuestobeenhancedtoaddressmorecomplextrafficsituations(e.g.AdjacentCenterMetering(ACM)andEnRouteDepartureCapability(EDC))MTCD&URETIntheUS,UserRequestEvaluationTool(URET)takespaperstripsoutoftheequationforEnRoutecontrollersatARTCCsbyprovidingadisplaythatshowsallaircraftthatareeitherinorcurrentlyroutedintothesector.InEurope,severalMTCDtoolsareavailable:iFACTS(NATS),VAFORIT(DFS),NewFDPS(MUAC).TheSESAR[12]ProgrammeshouldsoonlaunchnewMTCDconcepts.URETandMTCDprovideconflictadvisoriesupto30minutesinadvanceandhaveasuiteofassistancetoolsthatassistinevaluatingresolutionoptionsandpilotrequests.ModeS:providesadatadownlinkofflightparametersviaSecondarySurveillanceRadarsallowingradarprocessingsystemsandthereforecontrollerstoseevariousdataonaflight,includingairframeuniqueid(24bitsencoded),indicatedairspeedandflightdirectorselectedlevel,amongstothers.CPDLC:ControllerPilotDataLinkCommunicationsallowsdigitalmessagestobesentbetweencontrollersandpilots,avoidingtheneedtouseradiotelephony.ItisespeciallyusefulinareaswheredifficulttouseHFradiotelephonywaspreviouslyusedforcommunicationwithaircraft,e.g.oceans.ThisiscurrentlyinuseinvariouspartsoftheworldincludingtheAtlanticandPacificoceans.ADSB:AutomaticDependentSurveillanceBroadcastprovidesadatadownlinkofvariousflightparameterstoairtrafficcontrolsystemsviatheTransponder(1090MHz)andreceptionofthosedatabyotheraircraftinthevicinity.Themostimportantistheaircraft'slatitude,longitudeandlevel:suchdatacanbeutilizedtocreatearadarlikedisplayofaircraftforcontrollersandthusallowsaformofpseudoradarcontroltobedoneinareaswheretheinstallationofradariseitherprohibitiveonthegroundsoflowtrafficlevels,ortechnicallynotfeasible(e.g.oceans).ThisiscurrentlyinuseinAustralia,CanadaandpartsofthePacificOceanandAlaska.TheElectronicFlightStripsystem(estrip):AsystemofelectronicflightstripsreplacingtheoldpaperstripsisbeingusedbyseveralServiceProviders,suchasNAVCANADA,MASUAC,DFS,DECEA.EstripsallowscontrollerstomanageelectronicflightdataonlinewithoutPaperStrips,reducingtheneedformanualfunctions,creatingnewtoolsandreducingtheATCO'sworkload.ThefirstselectronicflightstripssystemswereindependentlyandsimultaneouslyinventedandimplementedbyNAVCANADAandSaipherATCin1999.TheNAVCANADAsystemknownasEXCDS[13]andrebrandedin2011toNAVCANstripsandSaipher'sfirstgenerationsystemknownasSGTC,whichisnowbeingupdatedbyits2ndgenrerationsystem,theTATICTWR.DECEAinBrazilistheworld'slargestuserofTowerestripssystem,rangingfromverysmallairportsuptothebusiestones,takingtheadvantageofrealtimeinformationanddatacollectionfromeachofmorethan150sitesforuseinATFM,BillingandStatistics.ScreenContentRecording:HardwareorsoftwarebasedrecordingfunctionwhichispartofmostElectronicFlightProgressStripSystematSoPauloIntl.ControlTowerGroundControlmodernAutomationSystemandthatcapturesthescreencontentshowntooftheATCO.Suchrecordingsareusedforalaterreplaytogetherwithaudiorecordingforinvestigationsandposteventanalysis.[14]CommunicationNavigationSurveillance/AirTrafficManagement(CNS/ATM)systemsarecommunications,navigation,andsurveillancesystems,employingdigitaltechnologies,includingsatellitesystemstogetherwithvariouslevelsofautomation,appliedinsupportofaseamlessglobalairtrafficmanagementsystem.[15]Airnavigationserviceproviders(ANSPs)andairtrafficserviceproviders(ATSPs)AzerbaijanAzrAeroNaviqasiya(http://www.canso.org/cms/showpage.aspx?id=110)AlbaniaAgjenciaNacionaleeTrafikutAjror(http://www.anta.com.al/index.php?option=com_content&view=article&id=66&Itemid=60)AlgeriaEtablissementNationaldelaNavigationArienne(ENNA)(http://www.enna.dz)ArmeniaArmenianAirTrafficServices(ARMATS)(http://www.armats.com)AustraliaAirservicesAustralia(StateOwnedCorporation)andRoyalAustralianAirForceAustriaAustroControlBelarusRepublicanUnitaryEnterprise"(BelarusianAirNavigation)"(http://www.avia.by/page616ru.html)BelgiumBelgocontrol(http://www.belgocontrol.be/)BrazilDepartamentodeControledoEspaoAreo(ATC/ATMAuthority)andANACAgnciaNacionaldeAviaoCivil(http://www.anac.gov.br)(CivilAviationAuthority)BulgariaAirTrafficServicesAuthority(http://www.atsa.bg/)CanadaNAVCANADAformerlyprovidedbyTransportCanadaandCanadianForcesCentralAmericaCorporacinCentroamericanadeServiciosdeNavegacinArea(http://www.cocesna.org)GuatemalaDireccinGeneraldeAeronuticaCivil(DGAC)(http://www.dgac.gob.gt/)ElSalvadorHondurasNicaraguaCostaRicaDireccinGeneraldeAviacinCivil(http://www.dgac.go.cr/)BelizeChileDireccinGeneraldeAeronuticaCivil(DGAC)(http://www.dgac.gob.cl/)ColombiaAeronuticaCivilColombiana(UAEAC)(http://www.aerocivil.gov.co)CroatiaHrvatskakontrolazraneplovidbe(CroatiaControlLtd.)(http://www.crocontrol.hr)CubaInstitutodeAeronuticaCivildeCuba(IACC)(http://www.cubagob.cu/des_eco/iacc/home.htm)CzechRepubliczenletovhoprovozuR(http://www.rlp.cz/)DenmarkNaviair(DanishATC)DominicanRepublicInstitutoDominicanodeAviacinCivil(IDAC)(http://www.idac.gov.do/)"DominicanInstituteofCivilAviation"EstoniaEstonianAirNavigationServices(http://www.eans.ee/)EuropeEurocontrol(EuropeanOrganisationfortheSafetyofAirNavigation)FinlandFinaviaFranceDirectionGnraledel'AviationCivile(DGAC)(http://www.aviationcivile.gouv.fr/):DirectiondesServicesdelaNavigationArienne(DSNA)(http://www.dsnadti.aviationcivile.gouv.fr/presentation/frpresent.html)(Governmentbody)GeorgiaSAKAERONAVIGATSIA,Ltd.(http://airnav.ge/en/)(GeorgianAirNavigation)GermanyDeutscheFlugsicherung(GermanATCStateownedcompany)GreeceHellenicCivilAviationAuthority(HCAA)HongKongCivilAviationDepartment(CAD)HungaryHungaroControlMagyarLgiforgalmiSzolglatZrt.(http://www.hungarocontrol.hu/en/)(HungaroControlHungarianAirNavigationServicesPte.Ltd.Co.)IcelandISAVIAIndonesiaAirNavIndonesia(http://www.airnavindonesia.co.id/)IrelandIrishAviationAuthority(IAA)IndiaAirportsAuthorityofIndia(AAI)(underMinistryofCivilAviation,GovernmentOfIndiaandIndianAirForce)IraqIraqiAirNavigationICAAIsraelIsraeliAirportsAuthority(IIA)[1](http://www.iaa.gov.il/rashat/enUs/Rashot)ItalyEnteNazionaleAssistenzaalVolo(ENAV)andItalianAirForceJamaicaJCAA(JamaicaCivilAviationAuthority)(http://www.jcaa.gov.jm/)JapanJCAB(JapanCivilAviationBureau)(http://www.mlit.go.jp/koku/)LatviaLGS(LatvianATC)(http://www.lgs.lv)LithuaniaANS(LithuanianATC)(http://www.ans.lt)LuxembourgLuxembourgATC(http://www.atc.lu)MacedoniaDGCA(MacedonianATC)(http://www.dgca.gov.mk)MalaysiaDCADepartmentofCivilAviation(http://www.dca.gov.my)MaltaMaltaAirTrafficServicesLtd(http://www.maltats.com)MexicoServiciosalaNavegacinenelEspacioAreoMexicano(http://www.seneam.gob.mx)NepalCivilAviationAuthorityofNepal(http://www.caanepal.org.np)NetherlandsLuchtverkeersleidingNederland(LVNL)(DutchATC)http://www.eurocontrol.nlEurocontrol(EuropeanareacontrolATC)(http://www.lvnl.nl)NewZealandAirwaysNewZealand(StateOwnedEnterprise)NorwayAvinor(Stateownedprivatecompany)OmanDirectorateGeneralofMeteorology&AirNavigation(http://www.caa.gov.om/eng/index.php)(GovernmentofOman)PakistanCivilAviationAuthority(underGovernmentofPakistan)PeruCentrodeInstruccindeAviacinCivilCIAC(http://www.corpac.gob.pe/ciac/ciac.asp)CivilAviationTrainingCenterPhilippinesCivilAviationAuthorityofthePhilippines(CAAP)(underthePhilippineGovernment)PolandPolishAirNavigationServicesAgency(PANSA)PortugalNAV(http://www.nav.pt)(PortugueseATC)PuertoRicoAdministracionFederaldeAviacionRomaniaRomanianAirTrafficServicesAdministration(ROMATSA)(http://www.romatsa.ro)RussiaFederalStateUnitaryEnterprise"StateATMCorporation"(http://www.gkovd.ru)SaudiArabiaGeneralAuthorityofCivilAviation(GACA)(http://www.gaca.gov.sa)SeychellesSeychellesCivilAviationAuthority(SCAA)(http://www.scaa.sc)SingaporeCivilAviationAuthorityofSingapore(CAAS)SerbiaSerbiaandMontenegroAirTrafficServicesAgencyLtd.(SMATSA)SlovakiaLetovprevdzkovslubySlovenskejrepubliky(http://www.lps.sk/)SloveniaSloveniaControl(http://www.sloveniacontrol.si)SouthAfricaAirTrafficandNavigationServices(ATNS)(http://www.atns.co.za)SpainAENAnowAENAS.A.(SpanishAirports)andENAIRe(ATC&ATSP)[16]SwedenLFV(GovernmentBody)SwitzerlandSkyguideTaiwanANWS(CivilAeronauticalAdministration)(http://www.anws.gov.tw/eng/index.php)ThailandAEROTHAI(AeronauticalRadioofThailand)(http://www.aerothai.co.th/)TrinidadandTobagoTrinidadandTobagoCivilAviationAuthority(TTCAA)TurkeyDGCA(TurkishDirectorateGeneralofCivilAviation)(http://www.shgm.gov.tr/)UnitedArabEmiratesGeneralCivilAviationAuthority(GCAA)(http://www.gcaa.ae)UnitedKingdomNationalAirTrafficServices(NATS)(49%StateOwnedPublicPrivatePartnership)UnitedStatesFederalAviationAdministration(FAA)(GovernmentBody)UkraineUkrainianStateAirTrafficServiceEnterprise(UkSATSE)(http://uksatse.ua/index.php?lang=en)VenezuelaInstitutoNacionaldeAviacinCivil(INAC)(http://www.inac.gob.ve/)ProposedchangesIntheUnitedStates,somealterationstotrafficcontrolproceduresarebeingexamined.TheNextGenerationAirTransportationSystemexamineshowtooverhaultheUnitedStatesnationalairspacesystem.Freeflightisadevelopingairtrafficcontrolmethodthatusesnocentralizedcontrol(e.g.airtrafficcontrollers).Instead,partsofairspacearereserveddynamicallyandautomaticallyinadistributedwayusingcomputercommunicationtoensuretherequiredseparationbetweenaircraft.[17]InEurope,theSESAR[12](SingleEuropeanSkyATMResearch)Programmeplanstodevelopnewmethods,technologies,procedures,andsystemstoaccommodatefuture(2020andbeyond)airtrafficneeds.Manycountrieshavealsoprivatizedorcorporatizedtheirairnavigationserviceproviders.[18]ChangeinregulationinadmittanceforpossibleA.T.C.'sregardingtheireyerefractionandcorrectionthereofbytechnologyhasbeenproposed.ATCregulationsintheUnitedStatesFAAControlTowerOperators(CTO)/AirTrafficControllersuseFAAOrder7110.65astheauthorityforallproceduresregardingairtraffic.FormoreinformationregardingAirTrafficControlrulesandregulations,refertotheFAA'swebsite.[19]SeealsoAirsafetyAirtrafficserviceBashkirianAirlinesFlight2937&DHLFlight611midaircollisionCivilAirNavigationServicesOrganisationReferencesCivilAirNavigationServicesOrganisationFlightlevel(FL)ForwardAirControllerFlightInformationServiceOfficerFlightplanningFlighttrackingGlobalAirTrafficManagementIFATCA(InternationalFederationofATCAssociations)Linesman/MediatorProfessionalAirTrafficControllersOrganizationTenerifedisasterTowerenroutecontrol(TEC)VirtualAirTrafficSimulationNetwork(VATSIM)Zagrebmidaircollision1. "FAA7110.65211"(http://www.faa.gov/air_traffic/publications/atpubs/ATC/atc0201.html).2. "IDAOFAQ"(http://www.icao.int/icao/en/trivia/peltrgFAQ.htm#23).Archived(http://web.archive.org/web/20090220142943/http://icao.int/icao/en/trivia/peltrgFAQ.htm)fromtheoriginalon20February2009.Retrieved20090303.3. GreenJerseyWebDesign."HeritageLocationsSouthEastSurreyCroydonAirport"(http://www.transportheritage.com/findheritagelocations.html?sobi2Task=sobi2Details&catid=91&sobi2Id=273).Retrieved3July2015.4. FAAHISTORICALCHRONOLOGY,192619965. "TerminalRadarApproachControlFacilities(TRACON)"(http://www.faa.gov/about/office_org/headquarters_offices/ato/tracon/).FederalAviationAdministration.Retrieved22February2014.6. "crashreport"(http://www.tsb.gc.ca/eng/rapportsreports/aviation/1996/a96a0207/a96a0207.asp).tsb.gc.ca.retrievedonAugust21,20107. Breitler,AlanandKirk,Kevin(September1996)."EffectsofSectorComplexityandControllerExperienceonProbabilityofOperationalErrorsinAirRouteTrafficControlCenters".CenterforNavalAnalysesDocument(IPR950092){{inconsistentcitations}}8. "WhatisanAbbreviatedAircraftCallSign?*"(http://atccommunication.com/whatisanabbreviatedaircraftcallsign).ATCCommunication.Retrieved3July2015.9. "AirTrafficControl"(https://sites.google.com/site/zagorakis1977/theory/airtrafficcontrol/technology).Retrieved4December2012.10. "Lefiletdesauvegarderesserresesmailles"(https://web.archive.org/web/20090327181434/http://www.dgac.fr/html/publicat/av_civil/them_1/them_1_34_35.pdf)(PDF).dgac.fr(inFrench).Archivedfromtheoriginal(http://www.dgac.fr/html/publicat/av_civil/them_1/them_1_34_35.pdf)(PDF)onMarch27,2009.11. "TechnicalSessions"(http://www.usenix.org/events/usenix02/tech/techthurs.html).usenix.org.Retrieved5December2010.12. SESAR(http://www.eurocontrol.int/sesar/public/subsite_homepage/homepage.html)13. http://www.navcanada.ca/NavCanada.asp?Language=en&Content=ContentDefinitionFiles\TechnologySolutions\products\IIDS\excds\default.xml14. "SolutionsusingEpiphanproducts"(http://www.epiphan.com/solutions_new/?arid=995).EpiphanVideocapture,stream,record.Retrieved3July2015.15. "CNS/ATMSYSTEMS"(https://web.archive.org/web/20111109123519/http://www.icao.int/icao/en/ro/rio/execsum.pdf)(PDF).icao.int.p.10.Archivedfromtheoriginal(http://www.icao.int/icao/en/ro/rio/execsum.pdf)(PDF)onNovember9,2011.16. "AcercadeENAIREENAIREInformacincorporativa"WikimediaCommonshasmediarelatedtoAirtrafficcontrol.ExternallinksU.S.CentennialofFlightCommissionAirTrafficControl(http://www.centennialofflight.gov/essay/Government_Role/Air_traffic_control/POL15.htm)TheshortfilmATRAVELERMEETSAIRTRAFFICCONTROL(1963)(https://archive.org/details/gov.archives.arc.43449)isavailableforfreedownloadattheInternetArchiveNASAvideoofUSairtraffic(http://www.youtube.com/watch?v=8pYiC7bTUxQ)Retrievedfrom"https://en.wikipedia.org/w/index.php?title=Air_traffic_control&oldid=674714954"Categories: Airtrafficcontrol RadarThispagewaslastmodifiedon5August2015,at17:41.TextisavailableundertheCreativeCommonsAttributionShareAlikeLicenseadditionaltermsmayapply.Byusingthissite,youagreetotheTermsofUseandPrivacyPolicy.WikipediaisaregisteredtrademarkoftheWikimediaFoundation,Inc.,anonprofitorganization.16. "AcercadeENAIREENAIREInformacincorporativa"(http://www.enaire.es/csee/Satellite/Enaire/es/Enaire.html).Retrieved3July2015.17. "Wired4.04:FreeFlight"(http://www.wired.com/wired/archive/4.04/es.faa.html).Retrieved3July2015.18. McDougall,GlenandRoberts,AlasdairS(August15,2007)."CommercializingAirTrafficControl:HavetheReformsWorked?".CanadianPublicAdministration.p.Vol.51,No.1,pp.4569,2009.SSRN1317450(https://ssrn.com/abstract=1317450).19. "AirTrafficPlansandPublications"(http://www.faa.gov/documentlibrary/media/order/atc.pdf)(PDF).FAA.Retrieved5December2010.