Optimising runway capacity - Luchtvaartfeiten · This factsheet focuses on the possibilities for airports to cope with the predicted demand. Amsterdam’s Schiphol Airport in the

Optimising runway capacity Ensuring a competit ive future for Europe’s busiest airports

Optimizingrunwaycapacity

IntroductionInSeptemberof2015,Eurocontrolmadeaseven-yearforecastofflightmovements,predictingacontinuousgrowthofIFRmovements,asseeninFigure1.1Eurocontrolalsocollectsinformationdirectlyfromairportstocalculateeffectiveannualcapacityfigures.Theypredictthatoverthenext7years,thecapacityoftheentireaviationsystemisexpectedtoincreaseby5.6%2.Theyconcludethatconstraintsatairportswillpreventtheseairportsfromaccommodatingflightdemandby2021.2Therefore,changesinthecurrentsituationarenecessary.Thisfactsheetfocusesonthepossibilitiesforairportstocopewiththepredicteddemand.Amsterdam’sSchipholAirport in theNetherlandsservesasagoodexample.Duringpeakhours, trafficdemand isatSchiphol’smaximumcapacity.Schipholthereforeneedstogrowtokeep itsmarketshareandtoaccommodatethe increasingnumberofaircraftmovementsat theairport.However, itsgrowth islimitedbyinternalandexternalfactors.Noiseandenvironmentalregulationsmeanthattheairportcannotbuildanotherrunway.4Externalsafetyregulations,meteorologicalconditions,airportcapacity(activerunwaycombinationsarelimitedbecausesomerunwaysintersect)andairspacecapacityalsoplayarole.3However,theairportcoulduseitscurrentrunwaysmoreefficiently.Thequestionis:Howcanairportsoptimizerunwaycapacitywhiletakingintoaccountmeteorologicalconditionsandsafetyrequirements?


Whatisrunwaycapacity?Runwaycapacity isdefinedasthenumberofaircraftmovementsthatcanbesafelyoperatedasdeterminedbyaeronauticalauthorities.Thisisusuallystated as the total number of landings and take-offs per hour.5 Runwaycapacity depends on issues such as runway availability, the number andlayoutofexits(taxiwaysconnectedtotherunway),operationalproceduresand meteorological conditions such as wind speed and direction, andvisibility.6For example, the VEM (Veiligheid, Efficiency en Milieu) performancestandardfromtheLVNL(LuchtverkeersleidingNederland),writtenin2015,displays the runway and ground capacity for the most preferred 2+1runway combinations during inbound (Figure 2) and outbound (Figure 3)peakmodesrespectively.Thesecapacitiesapplybetween06:30and22:30.7

Schiphol’scurrentpeakhourcapacityisalreadyhigh.Howcanthiscapacitybe increased to accommodate growth in the number of aircraftmovements? The answermay lie in the construction of high-speed exits,time-based separation, a re-categorizationofwake turbulence categories,ortheuseofothernavigationsystems.

Figure2:Runwaycapacity innumbersofmovementsperhourandper10minutes for thetwo most preferred inbound peak mode runway combinations. Reprinted from VEMperformancestandard,byLVNL,2015.

Figure1:Numberofadditionalmovementsper day foreachstate (2021v2014).Reprintedfrom Seven-Years Forecast of flightmovements document, by Eurocontrol, 2015, Retrievedfrom:https://www.eurocontrol.int/articles/forecasts


9=forcrosswindlessthan20knots

Figure3:Runwaycapacityinnumberofmovementsperhourandper10minutesforthetwomost preferred outbound peak mode runway combinations. Reprinted from VEMperformancestandard,byLVNL,2015.

HighspeedexitsreducerunwayoccupancytimeA key indicator for runway capacity is Runway Occupancy Time (ROT).8Duringthearrivalofanaircraft,ROTisdefinedasthetimeintervalbetweentheaircraftcrossingthethresholdoftherunwayandthetailoftheaircraftleavingtherunway.Runwaycapacity isoftenlimitedbyROTbecauseonlyone aircraft is allowed to use the runway at any given time. The leadingaircraftmust firstvacatetherunwaybeforethetrailingaircraft isallowedtocrossthethreshold.ROT can be reduced through the use of high-speed exits. These exits arenotperpendiculartotherunway,but insteaduseasmallerangleallowingaircrafttovacatesoonerandathigherspeeds,reducingROT.

Time-basedseparation,rediscoveredTo explain the concept of time-based separation (TBS) some basicinformation about aircraft separation is needed. This information can bedivided intowhyaircraftneedtobeseparated in the firstplaceandwhatthecurrentlegislationstates.

Whydoaircraftneedtobeseparated?Themost obvious reason for separating aircraft, of course, is to preventcollisions. The European Aviation Safety Agency (EASA)9 has made itmandatory toprovideair trafficcontrol service toallaerodrometrafficatcontrolled aerodromes (SERA.8001). In SERA.8001, EASA defines acontrolled aerodrome as: “…an aerodrome at which air traffic controlserviceisprovidedtoaerodrometrafficregardlesswhetherornotacontrolzone exists,’’ (p. L 281/5).9 It defines air traffic control service as ‘’… aserviceprovidedforthepurposeof:(a)Preventingcollisions:• Betweenaircraft;and• Onthemanoeuvringareabetweenaircraftandobstructions;and(b)Expeditingandmaintaininganorderlyflowofairtraffic,‘’(p.L281/4).Therefore,atcontrolledaerodromestheair trafficcontrolserviceensuresaircraftseparation.Alessobviousreasontoseparateaircraftiswakevortexturbulence.Wakevortexturbulenceisdefinedasturbulencethatisgeneratedbythepassageof an aircraft in flight. It is generated from the point at which the noselandinggearofanaircraftleavesthegroundupontake-offandceasestobegeneratedwhenthenoselandinggeartouchesthegroundduringlanding.10It can be dangerous to fly within the wake turbulence of an aircraft.According to ICAODoc 9426,wake turbulence causes three basic effects:induced roll (Figure 2, www.myairlineflight.com, 2014), loss of height orrateofclimb,andpossiblestructuralstress.11Therefore,thesecondreasonto separate aircraft is to ensure a safe flight without wake turbulencedangers.


Figure4:waketurbulencevortices.Reprintedfrommyairlineflightwebsite,byunknown,

2014,retrievedfromhttp://www.myairlineflight.com/wake_turbulence.htmlWhatisthecurrentlegislationonaircraftseparation?Because EASA made it mandatory to provide separation, it also createdseparationrules.EASAstatesinPART-SERA.8010Separationminima:“Theselection of separation minima for application within a given portion ofairspace shall be made by the air navigation service provider (ANSP)responsible for the provision of air traffic services and approved by thecompetentauthorityconcerned.”9Thismeans that theairport’sANSPcancreate their own separation rules as long as they are approved by the‘competent authority concerned’. In the Netherlands, the ANSP for civiltraffic is the ‘Luchtverkeersleiding Nederland’ (LVNL). The competentauthorityis‘InspectieLeefomgevingenTransport’.12CollisionavoidanceseparationThe LVNLbased its ruleson ICAODoc4444 (PANS-ATM).13 ICAO states inchapter7.10.1ofDoc4444forarrivingaircraftthat:‘’A landing aircraft will not normally be permitted to cross the runwaythreshold on its final approach until the preceding departing aircraft has

crossed the end of the runway-in-use, or has started a turn, or until allprecedinglandingaircraftareclearoftherunway-in-use,’’(p.7-15).13This reflects thepreviously-addressed issueof limitingROT. Fordepartingaircraft,ICAODoc4444chapter7.9.2statesthat:‘’Adepartingaircraftwillnot normally be permitted to commence take-off until the precedingdepartingaircrafthascrossedtheendoftherunway-in-useorhasstartedaturnoruntilallpreceding landingaircraftareclearoftherunway-in-use,’’(p.7-14).13Buttherunwayseparationminimabetweenaircraftusingthesamerunwaymay be reduced in certain situations, as described in ICAO Doc 4444chapter 7.11.13 The conclusion of these rules is that ‘collision avoidanceseparation’ may be reduced at the airport’s own discretion in certainsituations,suchasvisualseparation.However,‘waketurbulenceavoidanceseparation’stillneedstobetakenintoaccount.When Air Traffic Control (ATC) separates the IFR flight from other flightswiththeaidof radar, ICAODoc4444chapter8.7.3prescribesaminimumseparation of 5.0 nautical miles (9.3 km).13 This may be reduced at thediscretion of the appropriate Air Traffic Services (ATS) authority to 3nautical miles (5.6 km) or even 2.5 nautical miles (4.6 km) when theconditionsdescribed in ICAODoc4444chapter8.7.3.2baremet13.Oneofthese conditions is that theaverageROTmustnotexceed50 seconds.AtSchiphol, the LVNL uses the approach separation rules as displayed inFigure5(LVNL,n.d).


Figure5:ApproachseparationrulesfromLVNL.ReprintedfromLuchtverkeersleiding

Nederlandwebsite,byLVNL,n.d.,retrievedfromhttps://www.lvnl.nl/over-ons/veiligheid/separatie-van-vliegtuigen.html

WaketurbulenceavoidanceseparationWaketurbulenceavoidanceseparationalsoneedstobetakenintoaccount.Wake turbulence differs depending on the aircraft in question. WaketurbulencecategoriesaredefinedinICAODoc4444chapter4.9as:“HEAVY(H)–allaircrafttypesof136,000kgormore;MEDIUM(M)–aircrafttypeslessthan136,000kgbutmorethan7,000kg;andLIGHT(L)–aircrafttypesof7,000kgor less’’(p.4-11).13ThenAirbusmade theAirbusA380,withamaximum take-off mass of approximately 560,000 kg. ICAO had toinvestigate whether these three wake turbulence categories weresufficient. After conducting investigations and writing state letters, ICAOcreatedaguideline in2008recommendinganewcategory.14Becausethevortices generated by theA380 aremore substantial than those of otheraircraft in the HEAVY wake turbulence category, as SUPER category wasintroducedforA380aircraft.According to ICAO Doc 4444 chapter 8.7.3.4, the wake turbulenceseparationasshowninFigure4andFigure5areappliedwhen:

a) an aircraft is operating directly behind another aircraft at thesamealtitudeorlessthan300m(1000ft)below;or

b) both aircraft using the same runway, or parallel runwaysseparatedbylessthan760m(2500ft);or

c) an aircraft is crossing behind another aircraft, at the samealtitudeorlessthan300m(1000ft)below(p.8-17).13

Figure6:Distance-basedwaketurbulenceseparationminima.ReprintedfromICAODoc

4444,byICAO,2007,retrievedfromhttp://www.icao.int/EURNAT

Figure7:SeparationbetweenSUPERandothercategories.ReprintedfromTEC/OPS/SEP–

08-0294.SLG,byICAO,2008,retrievedfromhttps://www.eurocontrol.int/sites/ICAOdescribesinDoc4444chapter5.8thatwhentheaerodromecontrolleruses non-radar separation, an IFR arrival/departure must be separatedfrom other aircraft with time-based wake turbulence separation.13 Thefollowing rules apply for arriving aircraft: A MEDIUM aircraft behind aHEAVYaircraftneedsaseparationof2minutes.13ALIGHTaircraftbehindaHEAVYorMEDIUMaircraft needs a separationof 3minutes.OneminutemustbeaddedforanaircraftfollowinganA380.14


For departing aircraft, a minimum separation of 2 minutes should beapplied between a LIGHT orMEDIUM aircraft taking off behind a HEAVYaircraft or a LIGHT aircraft taking off behind a MEDIUM aircraft.13 Aminimum separation of 3 minutes should be applied for a LIGHT orMEDIUMaircraftand2minutes foranon-A380-800HEAVYaircraft takingoff behind an A380-800 aircraft.14 One exception applies for departuresfromintermediatepartsofthesamerunway.Then,aminimumseparationof3minutesisneededforaconfigurationwithLIGHT,MEDIUMandHEAVYaircraft.13 A separation minimum of 4 minutes should be applied for aLIGHTorMEDIUMaircraftwhentakingoffbehindanA380-800aircraft.14Time-basedseparation?Time-basedseparation(TBS)alreadyexistsbutitisonlyusedwhenaircraftare not separated by the use of radar. This is probably because it is lessaccurate in contrast to distance-based separation (DBS). DBS can bevisualized on a radar screen or a similar device. TBS limitsmay thereforepreferably be translated into DBS minima. There is one disadvantage ofseparation DBS: when an aircraft is on final approach and the headwindcomponent increases, the groundspeed drops. This results in a reducedlanding rate,which leads to increasedairborneholdingsanddelays.15TBSdoesnotsufferfromwindinfluences.TheinfluencesoftheweatherThe ICAO introduced the current aircraft separation standards in the1970’s. These standards are based on the worst meteorologicalconditions.16Innormalconditions,runwaycapacitycanbeincreased.16NATS, theEnglishANSP,conductedresearchandtogetherwithLockheed-Martin and developed a system that provides air traffic controllers withtime-based separation indicators on their radar.17 Lockheed-Martin alsodevelopedasystemcalledLIDAR(LightDetectionAndRanging)tomeasurewake vortex behaviour. LIDAR is a system that uses lasers instead oftraditional radio waves. Lasers are excellent for long-rangemeasurements18, which is necessary for determining wake vortex

turbulence at airports. Laser pulses are sent through the atmospheremeasuring wind speed by using Doppler-induced frequency shift on thebackscatteredlaserlight.16However,tounderstandthebehaviourofwakevortex turbulence, which is necessary for time-based separation, analgorithmmustbeusedtoextractwindspeedandairdirection.This LIDAR system, together with the time-based separation system, hasbeen installed at London Heathrow airport. Experiments with the LIDARsystemshowedthatiftheheadwindcomponentincreases,thewakevortexdecays faster and therefore the separation between aircraft can bereduced15.With this input, the time-based separation systemdynamicallyadjusts the separation between arrivals to maintain time separationequivalent to distance separation with a headwind of 5-7 knots.15Therefore, this system eliminates the disadvantages of the ‘simple time-based separation’ – not being able tomake the separation visible. It alsoprovides another advantage, in that it adapts to the current weathersituation.AnothersystemusedtomeasurewaketurbulencebehaviouristheX-bandRADARsystem.Thissystemuses‘normal’radarwavetechnologytodetectwakevortexturbulence.Whenavortexoccurs, radarwavesreturntothesystem as a consequence of Rayleigh scattering.16 Then the circulation ofthewakevortex,whichdetermines itsstrength, iscalculatedwiththeuseofDopplerfrequencies.19Real-world testswereperformed toevaluate thepotentialof the system.TheperformanceofX-bandRADARwastestedatParisOrlyairport (2006,2007)andatParisCharlesdeGaulleairport(2007).In2012,anothertestatParis Charles de Gaulle was performed (part of the Single European SkyATM Research program). Both tests proved that X-band RADAR iscomplementaryfordetectingwakevortexturbulence.16,19,20Thiscapabilityisnotrestrictedtoclearairconditions,butappliestoallweatherconditions(e.g.lighttoheavyrain,fog).


EuropeanWakeVortexRe-categorisation(RECAT-EU)Eurocontrol, inconsultationwithitsstakeholders,hasdevelopedaRECAT-EUprogrammeandindicatesthat:‘’during recent years, knowledge about wake vortex behaviour in theoperational environment has increased thanks to recorded data andimproved understanding of physical processes. It ismainly for this reasonthat it was possible to revise wake turbulence categorisation andcorrespondingseparationminimatoenableoptimisationofairportcapacityandefficiencywhilstmaintainingacceptablelevelsofsafety,’’(p.7).21

The RECAT-EU programbasically uses information from the LIDAR and X-band RADAR systems, and splits the HEAVY andMEDIUM ICAO categoryinto an upper and lower subcategory. Therefore, the separation minimabetween the (sub) categories can be reduced. Then, as Eurocontrolmentions, ‘Safety benefits are also delivered for some smaller aircrafttypes, by increasing their separation minima and/or change of categorygrouping,hencereducingtheriskofwaketurbulence-inducedaccidentsforthemostvulnerabletypes,’’(p.6).21The proposed new aircraft wake turbulence categories are displayed inFigure8.

Figure 8: Categorisation process and criteria for assigning an existing aircraft type intoRECAT-EU scheme. Reprinted from RECAT-EU document, by Eurocontrol, 2015, retrievedfromhttps://www.eurocontrol.int/download/publicationThe proposed new aircraft wake turbulence separations are displayed inFigure9andFigure10.


Figure 9: RECAT-EU WT distance-based separation minima on approach and departure.Reprinted from RECAT-EU document, by Eurocontrol, 2015, retrievedhttps://www.eurocontrol.int/download/publication(*)meansminimumradarseparation(MRS),setat2.5NM,isapplicableaspercurrentICAOdoc4444provisions.

Figure 10: RECAT-EU WT time-based separation minima on departure. Reprinted fromRECAT-EU document, by Eurocontrol, 2015, retrievedhttps://www.eurocontrol.int/download/publication

According to Eurocontrol, ATS can immediately expect benefits from thedeployment of this program. They specifically mention the followingbenefits:

• “The runway throughput benefits can reach 5% ormore duringpeakperiodsdependingonindividualairporttrafficmix.

•Foranequivalent throughput,RECAT-EUalsoallowsa reductionoftheoverallflighttimeforanarrivalordeparturesequenceoftraffic,andthis is beneficial to the whole traffic sequence. This may offer moreflexibilityfortheairtrafficcontrollerstomanagethetraffic.

• RECAT-EU will also enable more rapid recovery from adverseconditions, helping to reduce the overall delay and will also enableimprovements inATFMslotcompliancethroughtheflexibilityaffordedbyreduceddepartureseparations.

•Thegain incapacitycouldeven increase furtherby2020due toevolution of traffic mix. Indeed, the benefits are expected to furtherincreaseovertimeastheoverall fleetmix isforecastedtoevolvetowardslarger aircraft, a mitigation for the lack of runway capacity foreseen inEurocontrol’s2013‘ChallengestoGrowth’study,”(p.19).21The implementation of this programdoes not require the deployment ofnew technologies, but it does requireminor updates, adaptations to theapproachandtowertrafficsurveillancedisplay,andthepublicationofnewapplicableminima.Air traffic controllersmustalsobe trainedwith regardto the new categories and the flight crew must be made aware of thechange.21

AMicrowaveLandingSystemandaGround-BasedAugmentationSystemcanimproverunwaycapacityAnother interesting technological development concerns precisionapproach technology. Precision approach technology guides aircrafttowards the runway in both horizontal and vertical directions. The


Instrument Landing System (ILS),which uses two radio beams to providethepilotswithverticalandhorizontalguidance,iscurrentlythemostusedapproachsystem.22However,theILShassomedisadvantages.Themostimportantdisadvantageisthattheradiobeamsforhorizontalandverticalguidancearefixedandnarrow.Thereisalsoacriticalsensitiveareatopreventvehiclesandaircraft from interferingwith the ILSsignalduringILS operations (only in low visibility).23 As a result, aircraft have to besequenced and adequately separated into the range of the radio beams,whichcancauselandingdelays.Thisdoesnothelpwhenoptimizingrunwaycapacity.TheMicrowaveLandingSystem(MLS)wasdesignedtoreplacetheILSwithan advanced precision approach system that would overcome thesedisadvantages. The MLS radio beams have a large cover area and thesignalscannotbedisturbedbyothervehicles.Thismeansthatthecriticallysensitiveareaplaysnorole,therebyimprovingrunwaycapacityduringlowvisibility conditions. The aircraft have a larger area to intercept the radiobeams, which is helpful when separating aircraft (it delivers greaterflexibility). Implementing MLS therefore provides an opportunity tooptimizerunwaycapacity.23,24Another technological development designed to replace the ILS is theGround-BasedAugmentationSystem(GBAS).25TheGBASaugmentsGPStoprovideprecisenavigationservicefortheairportandsurroundingairspacewiththeuseofaVeryHighFrequency(VHF)datalink.SeveraloperationalGBAS are located in the USA, Germany, Australia, Spain, Switzerland andRussia. The navigation and approach operation can be used within 23nautical miles of the GBAS reference.26 In practice, this results in anapproachguidanceof20nauticalmiles.Thebenefitof theGBAS is that–contrary to ILS and MLS – a single system can support multiplerunways/approaches at an airport. Another benefit is that the GBASeliminates the critical sensitive area, just like the MLS, and providesaccuracyuptoonemetreinbothverticalandhorizontaldirections.Finally,

the GBAS uses less of the radio frequency spectrum. However, there aresomedownsidestothecurrentversionoftheGBAS.TheGBAScanonlybeused inCAT-I conditions (decisionheightnot lowerthan200feetwitheitheravisibilityofnotlessthan800metresorarunwayvisualrangenotlessthan550metresonarunwaywithatouchdownzoneandcentrelinelighting).Whenconditionsworsen,theGBAScannotbeusedandthe ILSorMLSneedstobeused.TheFederalAviationAdministration(FAA) focuses on validations standards for a GBAS approach service thatcoverstheCAT-IIIminima,whichresults inauseableGBASinlowvisibilityconditions. It is expected that this system (GAST-D) will be available in2018.

DiscussionThemainquestionaskedatthebeginningofthisdocumentwas:Howcanairportsoptimizerunwaycapacitywhiletakingintoaccountmeteorologicalconditionsandsafetyrequirements?Wehavediscussedfiveoptions.High-speedexitsareapossibilitytoreducetheROT.However,thisisnotanoption for every airport. For example, Amsterdam’s Schiphol Airportalready has high-speed exits on all but one runway, so the advantagesgainedthroughthissolutionwouldbeverysmall.Time-based separation isdesigned to increase runwaycapacity.However,thisonlymakesadifferenceunder the rightmeteorological conditions. Inlow visibility, air traffic controllers and ground controllerswill be at theirmaximum capacity. If time-based separation is used in these conditions,controllersmaypossiblyhavemoreaircraftthantheycansafelydealwith.TBSshouldfirstbetestedwithcaution,as itmaynotbethebestsolutionunder all conditions. Furthermore, it also requires the installation ofsystemsnecessarytovisualizetheseparationlimits,requiringATCtraining.


TheRECATprogrammesoundsverypromising,althoughitshouldbenotedthat thedeveloperof theprogramme itself forecast the results.Once thesolutionissimulatedtoanalysethesafetyeffects,andifEASAapprovesit,implementationwillmoveforwardquickly,astherearefewchangestobemade.MLShasbeenmentionedasatechnologythatcanpossiblyincreaserunwaycapacity. MLS has some advantages for the airport and the surroundingcommunity.27 However, aircraft modifications are required as not everyaircraft is equippedwithMLS.28 ForMLS to be as effective as possible atAmsterdam Airport Schiphol, every runway and aircraft must have theproper equipment for the MLS. This can be costly for the airport andoperators,andislikelytobeanunpopularsolution.TheMLSisnottheonlysystemthathasbeendevelopedtoincreaserunwaycapacity. The GBAS augments the existing GPS signal by broadcasting adifferential correction signal using VHF, which is transmitted by a GBAStransmitter.However,thissystemcanonlybeusedunderCAT-Iconditions.This means that the system, in today’s state, can never be a standalonelanding system, and a secondary system (such as ILS or MLS) must beinstalled alongside the GBAS to provide sufficient landing guidance in allweatherconditions.Some of the new procedures, such as RECAT-EU, are hard to implement.Currently,aircraftarelinedupontherunwayinthesequenceinwhichtheyapproach, and controllers have to take into account three aircraft waketurbulencecategories.ForRECAT-EUtobeeffective,aircraftmustbelinedup in a sequence thatprovides theminimum total time interval betweenlandings.Todothis,someaircraftmustholdandothermustbeexpedited.This will increase controller workload, raise complexity and congest theTMAevenmore.Before one of these possible solutions can be implemented, a VEM(Veiligheid, Efficiency enMilieu) analysis is needed. This analysis requires

specificinformationtowhichtheauthorsofthisfactsheethavelimitedornoaccess.

OverallconclusionAll of the techniques and procedures described in this fact sheet are, insome way, possible solutions for the problem of insufficient runwaycapacity. The high-speed exits could ensure a smaller ROT, whereby anaircraftmightbeallowedtohavelessdistancebetweenitandtheaircraftahead.When using time-based separation, aircraft separation limits can bedynamicallyadjusted,relatedtothecurrentweather.Thiscanbedonedueto the fact that a strong headwind will result in quicker wake vortexdissipation.Inordertoachievethistime-basedseparation,newtechnologymust be used, such as X-band RADAR and LIDAR radar systems incombination with algorithms to calculate the strength of the actualvortices.Legislationstatesthatseparationisnecessarytopreventcollisionsbetweenaircraftand toexpediteandmaintainanorderly flowofair traffic. It alsomakesclearthefactthataircraftmustbeseparatedatcertaindistancesasaresultofwakevortices.Bycreatingmoreaircraftcategories,asisdoneintheRECAT-EUprogram,waketurbulencecategoriesaretiedtothesizeoftheaircraft,whichpreventsunnecessaryseparation.TheMLSisdesignedasareplacementfortheILS.TheMLSprovidesalargeradiobeamcoverageandthesignalcannotbedisturbedbyothervehicles.Thismeans that the aircraftwill have a larger area to intercept the radiobeamsforguidancetotherunway.MLSalsohassomedisadvantages.Thelargestdisadvantage iscost– for theairportandfor theoperator.Finally,theGBASwasdesignedtouseGPSinanaviation-relatedmanner.AGBAStransmitter augments the GPS signal, which is located near the runway.Unfortunately,theuseofGBASiscurrentlylimitedtoCAT-Iconditionsand


therefore it cannot be used as stand-alone equipment for precisionapproaches.With the exception of the high-speed exits, all of these techniques andprocedures are still under development or in testing stages at otherairports.TheyalsocurrentlydeviatefromICAOstandards.BeforetheLVNL

and Amsterdam’s Schiphol Airportwill consider these solutions, theywillneedtoseeaVEManalysis.Theauthorsofthisfactsheetcannotcurrentlyconductthisanalysis.Butwehope that some of these solutions will turn out to be helpful. If nothingchanges,AmsterdamAirportSchipholwillfacecapacity-relatedproblemsinthefuture.

Glossary• Airborneholdings:Aircraftthatareflying incircles inthevicinityofan

airportbecauseofdelays.• Aircraftseparation:Thespacebetweentwoaircraft.• ANSP:AirNavigationServiceProvider.• ATC:AirTrafficControl.• ATFM:AirTrafficFlowManagement.• ATS:AirTrafficServices.• DBS:Distance-BasedSeparation.• EASA: EASA is an Agency of the European Union. As a Community

Agency,EASA isabodygovernedbyEuropeanpublic law; it isdistinctfrom the Community Institutions (Council, Parliament, Commission,etc.) and has its own legal personality. EASAwas set up by a Counciland Parliament regulation (Regulation (EC) 1592/2002 repealed byRegulation (EC) No 216/2008 and amended by Regulation (EC)1108/2009)andwasgivenspecificregulatoryandexecutivetasksinthefieldofcivilaviationsafetyandenvironmentalprotection(EASA,2013).

• Eurocontrol:EUROCONTROL,theEuropeanOrganisationfortheSafetyof Air Navigation, is an intergovernmental Organisation with 41Member States, committed to building, together with its partners, aSingle European Sky that will deliver the air traffic managementperformancerequiredforthetwenty-firstcenturyandbeyond.

• FAA:FederalAviationAdministration.Americanaviationauthoritywiththemission to provide the safest,most efficient aerospace system intheworld.

• Flightcrew:Personnelwhooperatetheaircraftwhileinflight.• Groundspeed:Speedoftheaircraftwithrespecttotheground.• Headwindcomponent:Componentofthewindwhichblowsagainstthe

directionoftravel.• ICAO: The International Civil Aviation Organization (ICAO) is a UN

specialized agency, established by States in 1944 to manage theadministrationandgovernanceoftheConventiononInternationalCivilAviation(ChicagoConvention)(ICAO,n.d.)

• IFR:InstrumentFlightRules.IFRflightdependsuponflyingbyreferenceto instruments in the flight deck, and navigation is accomplished byreferencetoelectronicsignals.

• Inducedroll:Purposely-inducedrollingmovementofanaircraft.• Peakhours:Aregularperiodofheavytraffic.• ROT:RunwayOccupancyTime.• TBS:Time-BasedSeparation.• Threshold of the runway: The runway thresholds are markings that

denotethebeginningandendofthedesignatedspaceforlandingandtakeoffundernon-emergencyconditions.

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DutchSummaryVerwachtingen van Eurocontrol voorspellen een voortdurende groei vanhet vliegverkeer. Als het vliegverkeer groeit zoals verwacht dan zullen deluchthavens deze omvang van het verkeer nietmeer aankunnen in 2021.

Optimizingrunwaycapacity Groeimogelijkheden voor luchthavens, zoals Amsterdam Airport Schiphol,zijn beperkt. Echter, een manier om te groeien is het toenemen van debaancapaciteit.Erzijnverschillendemogelijkhedenomdittedoen.Teneerste: laatvliegtuigendebaansnellerverlatenna landingenverlaagdaarmee de runway occupancy time. Bij sommige weersomstandighedenkandecapaciteitookvergrootwordendoorteseparerenopbasisvantijd.Daarnaast kunnen er meer wake turbulence categories gebruikt worden.Ook het gebruik van microwave landing systems en ground basedaugmentationsystemskunnendebaancapaciteitverhogenomdatermeervliegtuigentegelijkgebruikvankunnenmaken.AlsdesituatieopSchipholnietverandert,zullenerindetoekomstcapaciteitgerelateerdeproblemenoptreden. Sommige van de hier genoemde technologieën en procedureskunneneenuitkomstbiedenbijzulkeproblemen.ThisisaLuchtvaartfeiten.nl/AviationFacts.eupublication.Authors:DaanBoelhouwer,SandrineDoolhoff,KylianTimmermansEditorialstaff:R.J.deBoerPhDMsc,G.BoostenMSc&G.J.S.VlamingMScCopyingtextsisallowed.Pleasecite:‘Luchtvaartfeiten.nl(2016),OptimizingrunwaycapacityFactsheet,www.luchtvaartfeiten.nl’Luchtvaartfeiten.nlisaninitiativebytheAviationAcademyattheAmsterdamUniversityofAppliedSciences(HvA).Studentsandteachersshareknowledgewithpoliticiansandthegeneralpublictoensurethatdiscussionsarebasedonfacts.June2016