Analysis of New Arrival Operational Procedures in Terminal

Airspace

Joao Goncalo Patrıcio Duarte Anes Coelhojoaogoncalocoelho@tecnico.ulisboa.pt

Instituto Superior Tecnico, Lisboa, Portugal

June 2016

Abstract

In this dissertation a new arrival procedure to Lisbon airport was studied: Point Mergesystem. All the procedures of Lisbon terminal airspace, currently used, were analyzed, followedby the development of 8 scenarios with the implemented Point Merge system and, in addition,a reference scenario was created to work as a baseline. All the simulations were performedusing the RAMS Plus, a Fast-Time Simulations software, which allowed the development andresult analysis of these 9 scenarios. It was also analyzed the distance flown per arrival aircraftinside Lisbon TMA. In order to calculate the sectors capacity of each scenario the CAPANmethod was used.

Keywords: Capacity, CAPAN, Lisbon Terminal Airspace, Point Merge System, RAMS Plus

1. Introduction

Nowadays we live in global world, where peopletravel every time more and more increasing thenumber of flights at airports and Lisbon airportis no exception. According to EUROCON-TROL seven year forecast February 2016 theaverage annual traffic growth for Lisbon FlightInformation Region is 2.7%. As a result Por-tugal airspace Air Navigation Service ProviderNAV has been looking for solutions to increasethe capacity of Lisbon terminal airspace. Thisstudy is mainly focused on the analysis of thePoint Merge system, applied to Lisbon runway03 arrival routes, with the aim of enhancingthe capacity of Lisbon terminal airspace andalso to decrease the distance flown by the ar-rivals within the Lisbon TMA, in order to savefuel and its consequent benefits on economicand environmental level. It is also included inthis study the Montijo runway 01 as an aux-iliary to the runway 03. The development ofnew approach routes to the runway should takeinto account several factors. The work was

developed using EUROCONTROL guidelinesin terminal airspace design[1][2]. 9 terminalairspace scenarios were created including thecurrent baseline reference scenario. The other8 new scenarios were a Point Merge systemdesign type. The simulation of these scenar-ios was performed using the fast-time simula-tion tool: RAMS Plus.Sector capacity analy-sis was performed using EUROCONTROL CA-PAN method[3] relating controllers workloadwith number of flights received in each sector.

2. Airspace Concept Development

Traffic increase in terminal airspace places ademand on the responsible bodies of ATM totake measures to promote the optimization ofairspace, developing new procedures that allowmore efficient traffic flow. The development ofthese new procedures should take into accountthe objectives of the project and it is dividedinto four phases: planning, design, validationand implementation. In planning, the project

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objectives are defined, as well as the team thatwill be in charge of it. The controllers involvedin the design try to choose the best locationfor the new route so that the traffic controlcan be done in an efficient way. During thevalidation phase several simulations of the newairspace are made using analytical models, fast-time simulations and real-time simulations. Inthe last phase, it is done the training of all users(controllers, pilots) that will work in this newairspace and it is made the publication of allthe new procedures implemented. The processof developing a new airspace it is an iterativeprocess[1][2].

3. Point Merge System

The Point Merge system was developed in 2006by EUROCONTROL and it is already imple-mented in several European airports. ThePoint Merge is supported by P-RNAV systemsand allows to sequence efficiently the trafficon runway final approach, making possible thecontinuous descent approach, even with a lot oftraffic. The arrival routes which work with thePoint Merge system have a convergent geome-try that allows the path stretching or shorten-ing, and comprise a merge point - where trafficis integrated into the runway final approach -and sequencing legs - which should be isodis-tant and equidistant from the merge point andshall be separated from each other on lateraland vertical level[4].

Figure 1: Point Merge System Route Structure

The inner leg should be located at an higheraltitude than the outer leg to ensure that theflights using the latter do not cross the innerleg[4]. To simplify the separation between air-crafts and to sequencing them are employedRNAV STAR’s that allow an effective transi-tion from en-route phase to the runway ap-proaching phase of the flight, sequencing thetraffic into a single stream to the runway.The terminal airspace controllers must ensurethe separation between arrivals/arivals and ar-rivals/departures, and integrate the flights onthe runway landing sequence in a safe and effi-cient way[5]. In the Point Merge system, con-trollers need to give a ”Direct To” clearance sothat the flights turn out the leg to the mergepoint. In the approach to the merge point, thecontrollers must ensure that flights are prop-erly separated and if necessary give speed con-trol instructions to avoid the violation of theseseparations[4]. This new procedure is quite in-tuitive and the number of instructions givenby the controllers is smaller than in the con-ventional procedures, causing the reduction ofthe workload and permitting a more efficienthandling of the incoming traffic[6][7].

4. RAMS Plus

RAMS is an air traffic management fast-time simulation model developed at the EU-ROCONTROL Experimental Center (EEC)[8].Currently, this software is distributed and de-veloped by the company ISA Software underthe name of RAMS Plus. The RAMS Plusprovides gate-to-gate fast-time discrete-eventsimulation to quantify performance benefits forATM management decision support and it isused to measure a wide variety of ATM param-eters, such as workload, capacity and delays[9].To analyze these parameters it is necessary toset an airspace scenario with the properly con-figurations. Firstly, it is necessary to definean airspace sector through the definition of aspecific area and altitude, laying down on atri-dimensional space. It is also possible to es-tablish restrict areas, on a specific time sched-ule or day, and where only authorized aircraftcan fly[9]. In each sector there are two con-

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trollers: a planning controller (who checks thein and out traffic on the bordering sectors) anda tactical controller (who ensures the separa-tion between the aircraft)[8]. Despite the dif-ferences, they both are responsible for the traf-fic that flows over their sector and have definedseparations between the aircrafts to check con-flict situations. The controllers tasks are usedto indicate their workload and, consequently,the capacity of the airspace sectors. In whatconcerns to the routes, these are defined by aNAVAID sequence and linked to one runway.The routes can have holding points and restric-tions based on the velocity and altitude. Run-ways should be linked to one airport. The usercan also determine the occupation and schedul-ing time of the runway. Generally, it used a realtraffic sample in the simulations with the prop-erly aircraft performances[9]. The separationsparameters set for the controllers are used tocreate a conflict zone around the flight and aconflict occurs when two flights are containedin the conflict zone of the other[8].

Figure 2: Conflict Detection for Flights[8]

When RAMS detects a potential conflict situa-tion, an appropriate set of resolution rules areactivated to solve the conflict[8].

CAPAN Method

The CAPAN method was developed by EURO-CONTROL to evaluate sector capacities andnew airspace designs. According to CAPAN,the capacity of an ATC sector is considered tobe the maximum number of aircraft that canenter in it, in the period of an hour, without ex-

ceeding an acceptable level of workload for thecontroller (70% threshold)[3]. The RAMS isused to determine the controllers workload andthe number of sector entries. After that thesedata is related and, using a regression analy-sis, the function WL = F (Nsector) is obtained,with WL corresponding to controllers work-load and Nsector corresponding to the numberof flights that enter into the sectors. The sectorcapacity is the value of the intersection of thisfunction with the 70% threshold[3].

5. Lisbon Airspace

The Lisbon airport is the largest and themost important of Portugal. And in the lastyear, between January and September, it han-dled with 47.74% of all Portugal arrivals anddepartures[10][11]. The Lisbon airport de-clared capacity is 38 movements per hour[12].

Airspace

The Lisbon terminal control area comprises theairspace of Lisbon TMA, excluding the por-tion of Lisboa CTR within these limits. LisbonTMA can be divided in up to 4 sectors: TMAUpper Sector, TMA Lower Sector, APP Sector1 and APP Sector 2[13]. The vertical limits ofthese sectors are presented in Table 1.

TMAUpperSector

TMALowerSector

APPSector

1

APPSector

2

UpperLimit

FL 245 FL 145 FL 85 2000 ft

LowerLimit

FL 145 FL 55 2000 ft MSL1

Table 1: Lisbon TMA Vertical Limits

The most common configuration of LisbonTMA works only with 2 sectors (Lisbon TMAand Lisbon APP), without being divided intosub-sectors. And this configuration is repre-sented in Figure 3.

1Mean Sea Level

3

Figure 3: Lisbon TMA and APP Sectors

The Lisbon terminal airspace is surroundedby several restricted areas. These areas areused by the Portuguese military forces and con-ditioned the use of airspace, in particularly theareas of: Monte Real, Sintra and Montijo AirBases and the Field Firing Range of Alcochete.It’s only possible to use the Point Merge sys-tem in runway 03 approach routes because ofthis constraints.

Routes

The runway 03 of Lisbon airport has 9 RNAVdeparture routes (SID’s) and 10 RNAV arrivalroutes (STAR’s). These STAR’s have 4 holdingpoints: ADSAD, EKMAR, FTM and UMUPI.And the XAMAX4C STAR is only used whenthere is no military activity in Monte Real andSintra Air Bases[13]. The majority of the in-come traffic to Lisbon airport comes from theNorth and East, the same occurs with the out-come traffic from Lisbon airport.

Runways

The Lisbon airport has a two crossing runways:03/21 with 3800m and 17/35 with 2400m. It’sno possible the use of both runways at thesame time. The 17/35 runway is mostly usedas a taxiway. In addition to the runways thisairport has two civil and one military airportterminals[13]. The runway 03 is the most usedrunway of Lisbon airport for arrivals and depar-tures. The Montijo Air Base has a two crossingrunways like Lisbon airport: 01/19 with 2187mand 08/26 with 2448m. This Air Base is mostly

used by military aircrafts but sometimes it isused by civil flights to train certain procedures.The plan to use Montijo Air Base as an aux-iliary airfield of Lisbon airport establishes theuse of 01/19 runway, since it is parallel to 03/21runway of Lisbon airport. The use of 08/26runway of Montijo would be impossible sincethere would be a conflict with flights arrivingto Lisbon and to Montijo.

6. RAMS Plus Simulations

To achieve the goals proposed in the beginningof this study it was created 9 different scenar-ios. The first is a reference scenario and cor-responds to the actual procedures of Lisbonterminal airspace. In the other 8 it was usedthe Point Merge system with small changes be-tween them, that can be seen in the followingtable:

Scenarios Description

LPPT03 PM 1Lisbon’s Approach Routes with

Point Merge

LPPT03 PM A 1Same as LPPT03 PM 1 +

Direct Routes

LPPT03 PM AH 1Same as LPPT03 PM A 1 +

Holding Points

LPPT03 PM AHR 1Same as LPPT03 PM AH 1 +Restricted Areas Deactivated

LPPT03 PM AH2 1Same as LPPT03 PM AH 1 +

Sectorization of APP

LPPT03 PM AH 2Same as LPPT03 PM AH 1 +

Sequencing Legs at TMA

LPPT03-LPMT01 PM AH 1

Lisbon and Montijo’s ApproachRoutes with Point Merge

LPPT03-LPMT01 PM AH 2

Same asLPPT03-LPMT01 PM AH 1 +

Sequencing Legs at TMA

Table 2: Differences Between the Point MergeSystem Scenarios

The same traffic sample was used in all 9 sce-narios, with 231 departures and 222 arrivals.The airspace was divided into 4 sectors: Lis-bon FIR, Lisbon TMA, Lisbon APP and Lis-bon CTR. The introduction of Lisbon FIR andCTR was used to guarantee the correct sep-aration between flights that approach LisbonTMA (FIR) and the runway (CTR).

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LPPT03 REF

The reference scenario represents the actualconfiguration of Lisbon terminal airspace and itworks as a baseline for the other scenarios. Theroutes (Figure 4) and procedures were repli-cated as close as possible to the ones publishedin the portuguese AIP. The capacity of this sce-nario was calibrated in order to reach the ac-tual declared capacity for Lisbon airspace: 38movements per hour.

Figure 4: STAR’s (blue) and SID’s (red) -LPPT03 REF

LPPT03 PM 1

The Point Merge System was used in theseand in the following scenarios, maintaining thesame TMA point entries as the reference sce-nario. The sequencing legs are located in Lis-bon APP, with the inner leg 14 NM distantfrom the merge point and the outer 16 NM farfrom the same point. The SID’s used in thePoint Merge scenarios are the same as the onesused in the reference scenario.

Figure 5: STAR’s - LPPT03 PM 1

LPPT03 PM A 1

It was used the same configuration of theLPPT03 PM 1 scenario with the introductionof direct approach routes. If the traffic demandis not too high, the flights can use these directroutes instead of using the sequencing legs ofthe Point Merge system, flying a shorter path.

Figure 6: Direct Routes (Green) andPoint Merge System Routes (Blue) -LPPT03 PM A 1

LPPT03 PM AH 1

Holding points were used in this scenario whilekeeping the same routes and configuration ofthe LPPT03 PM A 1.

Figure 7: STAR’s (Blue) with the HoldingPoints (Orange) - LPPT03 PM AH 1

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LPPT03 PM AHR 1

The LPPT03 PM AH 1 scenario configurationwas used in this one with the restricted areasof Monte Real and Sintra deactivated. In thisscenario the flights that come from the Northcan use the STAR XAMAX4C.

LPPT03 PM AH2 1

The Lisbon airspace capacity is limited by theLisbon APP sector. This sector was divided intwo sub-sectors (APP Sector 1 and APP Sec-tor 2) to study if it is possible to increase thecapacity of Lisbon airspace with this configu-ration.

Figure 8: Sectors Vertical Profile -LPPT03 PM AH2 1

LPPT03 PM AH 2

The configuration of LPPT03 PM AH 1 wasused in this scenario with the relocation ofPoint Merge sequencing legs to the TMA (Fig-ure 7). With this new location of the sequenc-ing legs the Point Merge tasks (”Direct To”)will be executed by the TMA controllers in-stead of APP controllers, trying to reduce theworkload of the last ones.

Figure 9: STAR’s - LPPT03 PM AH 2

LPPT03-LPMT01 PM AH 1

In this scenario was used the Montijo 01 run-way as an auxiliary runway to Lisbon 03 run-way. The STAR’s (Figura 8) of both runwayshave the same Point Merge system, with thesequencing legs within the APP sector. It wasalso created a new set of SID’s (Figura 8) forboth runways to avoid conflicts with the depar-tures. The traffic sample used in this scenariowas the same as the one used in the others sce-narios with the difference that it was dividedfor both runways, with the traffic of Montijocorresponding to the flights of airlines that useLisbon airport Terminal 2[14].

Figure 10: STAR’s (blue) and SID’s (red) -LPPT03-LPMT01 PM AH 1

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LPPT03-LPMT01 PM AH 2

It was used the same configuration of theLPPT03-LPMT01 PM AH 2 scenario with therelocation of the sequencing legs to theTMA sector, like it was done in theLPPT03 PM AH 2 scenario and to study ifthis new locations of the Point Merge legs canreduce the APP controllers workload.

Figure 11: STAR’s (blue) and SID’s (red) -LPPT03-LPMT01 PM AH 2

7. Results and Discussion

The results from the 9 simulations wereanalyzed and will be presented with a briefdescription for each scenario. The Lisbonairspace capacity for all of the 9 scenariosrefers to the APP sector capacity, once it isthis sector that limits the capacity of Lisbonairspace in all of the scenarios.

LPPT03 REF

The following figures presents the controllersworkload, number of conflicts in the sector andnumber of flights in the sector obtained, withthe estimation of the capacity using the CA-PAN method.

Figure 12: APP Sector Workload, Flights andConflicts - LPPT03 REF

Figure 13: APP Sector Workload, Flights andConflicts - LPPT03 REF

The capacity is estimated in 38 movementsper hour, like it was already referred in theprevious section. The average distance flownby the arrivals inside the Lisbon terminalairspace is 97.78 NM.

LPPT03 PM 1

The controllers workload reduces comparedwith the reference scenario and the capacityincreases to 39 movements per hour. Theaverage distance flown by the arrivals is now111.87 NM, this is related to the increase ofthe approach routes lenght.

LPPT03 PM A 1

The introduction of the direct approach routesdecreases the average distance flown by thearrivals to 100.06 NM because this new routesare shorter than the Point Merge routes andthe majority of the flights uses it (76.73%).The APP sector capacity increases to 41movements per hour.

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LPPT03 PM AH 1

The integration of holding points in the ap-proach routes reduces the controllers workloadand the capacity increases to 42 movementsper hour. There is no significant changes inthe average distance flown by the aircraftscompared with the LPPT03 PM A 1 scenario.The number of flights sent to the holdingpoints and the average time they stayed thereis similar to the obtained in the referencescenario.

LPPT03 PM AHR 1

The values of the workload are similar to theones obtained in the previous scenario but thecapacity decreases to 41 movements per hour.The average distance flown by the arrivals is103.56 NM, with an increase of the averagedistance flown by the arrivals that entry in theLisbon TMA by XAMAX. This is because theSTAR used in this scenario (XAMAX4C) islonger than the one used in the other scenarios(XAMAX4A).

LPPT03 PM AH2 1

The results obtained for these scenario wereclose to the ones from LPPT03 PM AH 1scenario. The APP Sector 2 is practicallyunused and the APP Sector 1 receives thesame traffic as the APP sector from theLPPT03 PM AH 1 scenario, being the APPSector 1 the limiting scenario and its capacityremains unchanged in the 42 movements perhour.

LPPT03 PM AH 2

The results of the APP controllers work-load increased comparatively to the ones fromLPPT03 PM AH 1 scenario. This occurred be-cause the number of flights in the APP sectoralso increased. But its capacity remains in the42 movements per hour. In this scenario thesequencing legs where relocated to the TMAsector and the workload of TMA controllers in-crease as expected. There is also an increase inthe distance flown by the arrivals.

LPPT03-LPMT01 PM AH 1

The introduction of Montijo 01 runway as anauxiliary runway of Lisbon 03 runway has asignificant impact in the capacity of the APPsector, which increases to 44 movements perhour. And the average distance flown by theflights decreases to 98.89 NM, a result closeto the one obtained from the reference scenario.

LPPT03-LPMT01 PM AH 2

The APP and TMA controllers workloadincreases relatively to the one of LPPT03-LPMT01 PM AH 1 scenario. And its capacityremains unchanged in the 44 movementsper hour. There is also an increase in theaverage distance flown by the arriving aircraftsbecause the sequencing legs are now more faraway from the merge point comparatively toLPPT03-LPMT01 PM AH 1 scenario.

Design Adopted

The main objective of this study is to verify ifthe use of the Point Merge system in Lisbonterminal airspace could increase the capacityof the airspace. All of the 8 scenarios with thePoint Merge system implemented achieved thatgoal.

Scenarios CapacityAverage

Distance[NM]

LPPT03 REF 38 97.78

LPPT03 PM 1 39 111.87

LPPT03 PM A 1 41 100.06

LPPT03 PM AH 1 42 101.66

LPPT03 PM AHR 1 41 103.56

LPPT03 PM AH2 1 42 101.80

LPPT03 PM AH 2 42 109.05

LPPT03-LPMT01 PM AH 1

44 98.89

LPPT03-LPMT01 PM AH 2

44 110.16

Table 3: Capacity of Lisbon APP Sector andAverage Distance Flown by the Arrivals in theLisbon Terminal Airspace for the 9 Scenarios

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The two scenarios with Montijo 01 runwaypresents the best results for the capacity ofthe Lisbon APP sector: 44 movements perhour. Of these two it was choose the LPPT03-LPMT01 PM AH 1 design because the averagedistance flown by the arrivals is smaller than inthe other one, and it is almost the same of thevalues obtained in the reference scenario.

8. Conclusions

In this study was verified that Lisbon terminalairspace is quite conditioned by the militaryareas and as a result the Point Merge systemcould only be implemented in the approachroutes of the Lisbon 03 runway. It was alsoverified that the Lisbon APP is responsible forthe maximum capacity of this airspace with 38movements per hour.

The 8 scenarios with the Point Mergesystem show that system can be implementedin the Lisbon terminal airspace and all ofthem increase the capacity of Lisbon APPsector. This study also demonstrated that thebest results for the capacity were obtained inthe scenarios with Montijo 01 runway as anauxiliary of the Lisbon 03 runway.

Although it has improved the capacity ofLisbon APP sector, it has to take into ac-count that this study focused on fast-timesimulations and to validate this new proposaldesign must be conducted another studies inparticular real-time simulations.

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