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Preparation of Papers for AIAA Technical Conferences - Pegasus

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Analysis <strong>of</strong> the Validation objectives <strong>of</strong> the TITAN Concept<br />

<strong>of</strong> Operations (Turnaround Integration in Trajectory And<br />

Network)<br />

Andrea Villa García 1<br />

Universidad Politécnica de Madrid- ETSIA,Madrid, Spain<br />

This paper details the TITAN Concept <strong>of</strong> Operations Validation objectives analysis.<br />

TITAN is an advanced turnaround Operational Concept per<strong>for</strong>med as an integral part <strong>of</strong><br />

the aircraft trajectory. It is based on the principles <strong>of</strong> Collaborative Decision Making (CDM)<br />

and System Wide In<strong>for</strong>mation Management (SWIM). The TITAN validation approach was<br />

based on the application <strong>of</strong> the European Operational Concept Validation Methodology(E-<br />

OCVM). The Validation objectives assessment was per<strong>for</strong>med through the analysis <strong>of</strong><br />

simulation results from a discrete event, extended network queuing simulation model.<br />

Conclusions obtained from the validation activities show that the TITAN Operational<br />

Concept is able to deliver the expected per<strong>for</strong>mances in terms <strong>of</strong> efficiency, predictability,<br />

flexibility and cost-effectiveness. This paper describes the process, the results and the<br />

analysis per<strong>for</strong>med in the validation.<br />

Nomenclature<br />

ACT = Actual Completion Time<br />

AIRS = Airport In<strong>for</strong>mation Report Service<br />

AOBT = Actual Off-Block Time<br />

ASRS = Aircraft Status Report Service<br />

AST = Actual Start Time<br />

ATM = Air Traffic Management<br />

ATTT = Actual Turnaround Time<br />

BFIS = Baggage Flow In<strong>for</strong>mation Service<br />

ECT = Estimated Completion Time<br />

E-OCVM = European Standard Methodology <strong>for</strong> Operational Concepts<br />

EST = Estimated Start Time<br />

ETTT = Estimated Turnaround Time<br />

KPA = Key Per<strong>for</strong>mance Area<br />

KPI = Key Per<strong>for</strong>mance Indicator<br />

OBT = Off-Block Time<br />

PCT = Planned Completion Time<br />

PFIS = Passenger Flow In<strong>for</strong>mation Service<br />

PST = Planned Start time<br />

SOBT = Scheduled Off-Block Time<br />

TITAN = Turnaround Integration in Trajectory And Network<br />

μ = mean value<br />

σ = standard deviation<br />

1 Graduate student, Airports and Air Navigation Systems Department. andrea.villa.garcia@alumnos.upm.es.<br />

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I. Introduction<br />

ALIDATION is an iterative process by which the fitness <strong>for</strong> purpose <strong>of</strong> a new system or operational concept<br />

V being developed is established. It can also be understood as the assessment <strong>of</strong> the candidate solutions against<br />

the requirements. Validation is a process composed by several parts including the analysis <strong>of</strong> the Validation<br />

objectives and the identification <strong>of</strong> conclusions.<br />

Turnaround delays cause approximately 4/5 <strong>of</strong> late departures flights 1 . As part <strong>of</strong> the project, TITAN* carried<br />

out an analysis <strong>of</strong> the current situation <strong>for</strong> the turnaround process and an identification <strong>of</strong> the stakeholder´s problems<br />

and needs 2 . Based on this in<strong>for</strong>mation, TITAN developed a new operational concept 3 <strong>for</strong> the turnaround as an<br />

integral part <strong>of</strong> the trajectory. TITAN considered the landside processes within the principles <strong>of</strong> Collaborative<br />

Decision Making 4 (CDM) and System Wide In<strong>for</strong>mation Management 5 (SWIM). The TITAN concept <strong>of</strong> operations<br />

also included new in<strong>for</strong>mation services -called TITAN In<strong>for</strong>mation Services- which provide in<strong>for</strong>mation about<br />

passengers or baggage location, aircraft status or airport resources. This new operational concept aimed to improve<br />

turnaround predictability, flexibility, efficiency and cost-effectiveness.<br />

Validation activities were necessary to assess these goals and to provide operational feedback (enhancements<br />

and corrections) <strong>for</strong> the refinement <strong>of</strong> the operational concept.<br />

The first TITAN validation phase was based on the application <strong>of</strong> the European Operational Concept Validation<br />

Methodology 6 (E-OCVM) and aimed to reach the V1 maturity level. During next phase -V2 phase- the feasibility <strong>of</strong><br />

the concept was established. This paper focuses on the analysis <strong>of</strong> the Validation objectives corresponding to the V2<br />

phase.<br />

V2 validation activities were based on simulation results from a discrete event, extended network queuing<br />

simulation model (TITAN Model) 7 . This s<strong>of</strong>tware model was developed by the TITAN Consortium. The TITAN<br />

Model allowed emulating the processes and resources involved in the turnaround <strong>of</strong> an aircraft within a realistic<br />

operational environment. Variation <strong>of</strong> the parameters ensured the validation <strong>of</strong> a wide operational context. In the<br />

course <strong>of</strong> the simulations, data was recorded to identify the per<strong>for</strong>mance parameters.<br />

The simulation output data was analyzed in detail to assess validation objectives and KPI. The Validation<br />

objectives assessment was based on comparing the results from a scenario where the TITAN Concept was<br />

implemented with a baseline scenario (a scenario that represented the current situation).<br />

Following sections describe TITAN Concept Validation objectives and KPI, output data from the simulations<br />

and their relationship with the Validation objectives and the analysis <strong>of</strong> the objectives. Finally, conclusions about<br />

this analysis are presented.<br />

II. Validation objectives description<br />

TITAN consortium defined the following Validation objectives <strong>for</strong> the V2 phase.<br />

Exercise Id<br />

V2-01<br />

V2-02<br />

V2-03<br />

V2-04<br />

Validation Objectives<br />

To assess whether the TITAN concept meets the targeted per<strong>for</strong>mances levels <strong>for</strong> predictability,<br />

efficiency and flexibility.<br />

To assess the influence <strong>of</strong> passenger and baggage processes, especially under several unexpected<br />

situations (e.g. late passenger arrival or lost baggage).<br />

To assess the effect <strong>of</strong> disruptions on the per<strong>for</strong>mances levels <strong>for</strong> predictability, efficiency and<br />

flexibility.<br />

To validate the application <strong>of</strong> the TITAN services described in the Operational Concept (BFIS,<br />

PFIS, AIRS, ASRS).<br />

To assess whether the TITAN concept meets the targeted per<strong>for</strong>mances levels <strong>for</strong> cost<br />

effectiveness.<br />

Table 1. V2 Validation Objectives<br />

To define each Validation objective, they were specified as exercise objectives. Exercises objectives represent<br />

lower level validation objectives. They describe the goal <strong>of</strong> the exercise and the specific scenario where the<br />

objective needs to be evaluated. Each exercise objective is achieved by simulating one or several Validation<br />

scenarios.<br />

*TITAN was a 7th Framework Programme co-financed by the European Commission. Private companies related to the ATM context, Air<br />

Navigation Services Providers, Research and Development Centers and Universities <strong>for</strong>med the TITAN Consortium. See www.titan-project.eu<br />

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A Validation scenario is a specific scenario developed <strong>for</strong> the purposes <strong>of</strong> undertaking validation activities and to<br />

gather evidence relevant to the validation objective. Validation scenarios were built using the TITAN Model<br />

description language. For validation activities, one generic scenario and four specific scenarios (Late passenger,<br />

Increasing demand, Late arrival and Lack <strong>of</strong> resources) were defined (see Table 2) . Each Validation scenario was<br />

repeated varying several numerical parameters. As a result, there were around 260 different scenarios.<br />

Normal<br />

Airport<br />

Operation<br />

Disruption<br />

Generic<br />

Scenario<br />

Late<br />

Passenger<br />

Specific Validation Scenarios<br />

Increasing<br />

demand<br />

Late<br />

arrival<br />

Lack <strong>of</strong><br />

resources<br />

Current situation GEN-1a SPEC-1a SPEC-2a SPEC-3a SPEC-4a<br />

TITAN concept GEN-1b SPEC-1b SPEC-2b SPEC-3b SPEC-4b<br />

Current situation GEN-2a SPEC-1c SPEC-2c SPEC-3c SPEC-4c<br />

TITAN concept GEN-2b SPEC-1d SPEC-2d SPEC-3d SPEC-4d<br />

Table 2.Validation scenarios<br />

For each exercise objective, it was necessary to identify the sub-processes* where the objective needed to be<br />

evaluated and an indicator. After that, a success criteria <strong>for</strong> each exercise objective was established. Table 3 shows<br />

an example <strong>of</strong> some <strong>of</strong> the exercise objectives.<br />

Exercise Objective<br />

V2.01-A. Check whether<br />

standard deviation <strong>of</strong> <strong>of</strong>fblock<br />

time (AOBT-<br />

SOBT) with TITAN is<br />

reduced to 3 minutes.<br />

V2.02-D. Check whether<br />

variability <strong>of</strong> processes<br />

durations decreases with<br />

TITAN with respect to<br />

Non TITAN.<br />

Baseline Scenario/<br />

Scenario to be<br />

evaluated<br />

GEN1AExe1/<br />

GEN1BExe1<br />

GEN2AExe5&8/<br />

GEN2BExe5&8<br />

Indicator Process Success Criteria<br />

Total Delay:<br />

ACT-PCT<br />

ACT-AST<br />

Variability <strong>of</strong> ETTT<br />

Standard deviation <strong>of</strong><br />

(ACT-AST) - (ECT-<br />

EST)<br />

Table 3.Exercise objectives<br />

Off-Block<br />

All turnaround subprocesses<br />

TITAN Standard<br />

deviation <strong>of</strong> the Off -<br />

Block delayed time <<br />

3 min.<br />

σ <strong>of</strong> the turnaround<br />

sub-processes duration<br />

with TITAN < σ <strong>of</strong><br />

the turnaround subprocesses<br />

duration<br />

non-TITAN<br />

To per<strong>for</strong>m the analysis and ensure the obtention <strong>of</strong> coherent and comparable results,TITAN developed a<br />

Per<strong>for</strong>mance Framework 8 that defined the Key Per<strong>for</strong>mance Indicators (KPI) . KPI identify what in<strong>for</strong>mation had to<br />

be obtained to reach the TITAN per<strong>for</strong>mance objectives. These indicators quantitatively described the per<strong>for</strong>mance<br />

<strong>of</strong> the turnaround process. Table 4 shows the identification <strong>of</strong> the measurements needed to calculate each metric <strong>for</strong><br />

some KPI.<br />

KPI Metric Calculation <strong>of</strong> Metric Measurement<br />

Variability <strong>of</strong> ETTT Time Standard deviation <strong>of</strong> ATTT-<br />

ETTT<br />

Off Block punctuality Percentage % <strong>of</strong> flights compliant with<br />

AOBT- SOBT 15 min<br />

*Turnaround sub-processes considered in validation scenarios were: Baggage loading, baggage unloading, boarding, catering check-in, cleaning,<br />

de-boarding, in-blocks, <strong>of</strong>f-blocks, passport (only <strong>for</strong> international turnaround), re-fueling and security<br />

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III. Description and reliability <strong>of</strong> simulation data<br />

TITAM Model produced a file containing all per<strong>for</strong>mance parameters <strong>for</strong> each simulation. According to the<br />

analysis <strong>of</strong> the measurements and the indicators necessary <strong>for</strong> validation purposes, datasets were selected <strong>for</strong> each<br />

sub-process:<br />

PST: Planned Start time, according to schedule input data and processes definition.<br />

EST: Estimated –by the TITAN Model- Start Time, according to schedule, planned and updated durations<br />

<strong>of</strong> the previous processes.<br />

AST: Actual Start Time, real start time <strong>of</strong> a process.<br />

PCT: Planned Completion Time.<br />

ECT: Estimated Completion Time.<br />

ACT: Actual Completion Time.<br />

Using these output data, following parameters were calculated to assess the exercise objectives:<br />

ACT-PCT: Delay <strong>of</strong> the process with regard to the schedule.<br />

ACT-ECT: Delay <strong>of</strong> the process with regard to the model estimation.<br />

ACT-AST: Real duration <strong>of</strong> the process.<br />

PCT-PST: Schedule duration <strong>of</strong> the process.<br />

(ACT-AST) – (PCT-PST): Difference between the real duration and the schedule one.<br />

Number <strong>of</strong> (ACT-PCT)>15min.<br />

To assess output data reliability a statistical analysis <strong>of</strong> output data was carried out. Statistical analysis was<br />

per<strong>for</strong>med over the measurements that served to assess the exercise objectives:<br />

ACT-PCT: Delay <strong>of</strong> the process with regard to the schedule.<br />

ACT-ECT: Delay <strong>of</strong> the process with regard to the model estimation.<br />

ACT-AST: Real duration <strong>of</strong> the process.<br />

(ACT-AST) – (PCT-PST): Difference between the real duration and the schedule one.<br />

Percentage <strong>of</strong> processes in which (ACT-PCT) >15min<br />

The statistical parameters obtained were:<br />

Mean <strong>of</strong> each measurement <strong>of</strong> every turnaround process: It served to know the central tendency <strong>of</strong> the<br />

process measurement (process delay or process duration average).<br />

Standard deviation (σ) <strong>of</strong> every turnaround process: It served to know the dispersion <strong>of</strong> the data<br />

measurement (dispersion <strong>of</strong> the processes delays or processes durations).<br />

Confidence interval (C.I.) <strong>of</strong> the <strong>of</strong>f block process delay: It served to ensure reliability <strong>of</strong> the data<br />

measurement by calculating the interval that contained an established percentage (Confidence level, α)<br />

<strong>of</strong> the data measurement.<br />

Each Simulation scenario was run until the output data allowed obtaining a confidence level <strong>of</strong> 0.95 <strong>for</strong> the <strong>of</strong>fblock<br />

process delay and a confidence interval <strong>of</strong> 0.33 minutes (20 seconds). That means that 95% <strong>of</strong> the flights had a<br />

delay in <strong>of</strong>f block process within the interval <strong>of</strong> ±20 seconds around the mean <strong>of</strong> the delays <strong>of</strong> all <strong>of</strong>f blockprocesses.<br />

Following tables show the statistical data obtained <strong>for</strong> each simulation run. Numeric values correspond to GEN-<br />

1a scenario.<br />

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Process<br />

ACT-PCT<br />

Average<br />

ACT-ECT<br />

Average<br />

ACT-AST<br />

Average<br />

(duration<br />

average)<br />

(ACT-AST)<br />

– (PCT-<br />

PST)<br />

Average<br />

(duration<br />

deviation<br />

average)<br />

Number <strong>of</strong><br />

processes in<br />

which<br />

(ACT-<br />

PCT)>15min<br />

Percentage<br />

<strong>of</strong> processes<br />

in wich<br />

(ACT-<br />

PCT)>15min<br />

Boarding 0,31 -1,94 21,80 -1,20 135 8 %<br />

Security -31,60 -30,84 88,40 -31,60 0 0 %<br />

Baggage Unloading -2,21 -3,67 10,64 -5,23 74 4 %<br />

Table 5.Calculated means <strong>for</strong> GEN-1a scenario.<br />

Process<br />

ACT-PCT<br />

Standard deviation<br />

ACT-ECT<br />

Standard deviation<br />

ACT-AST<br />

Standard deviation<br />

(duration standard<br />

deviation)<br />

(ACT-AST)–<br />

(PCT-PST)<br />

Standard deviation<br />

(duration deviation<br />

standard deviation)<br />

Boarding 10,52 10,00 7,66 7,66<br />

Security 6,38 7,85 6,38 6,38<br />

Baggage Unloading 8,62 5,62 2,42 3,04<br />

Table 6.Calculated standard deviation <strong>for</strong> GEN-1a scenario.<br />

Finally, the confidence interval was calculated according to the number <strong>of</strong> measurements. For the presented<br />

example (GEN1AExe1) five simulations were run (each simulation contains 339 flights), and there<strong>for</strong>e the results<br />

had 339*5=1695 measurements <strong>of</strong> the delay in <strong>of</strong>f-block. The average <strong>of</strong> the <strong>of</strong>f- block delay was 3,44 minutes,<br />

with a standard deviation <strong>of</strong> 8,09 minutes and a confidence interval <strong>of</strong> 23 seconds. In other words, <strong>of</strong>f -block delay<br />

<strong>of</strong> 95% <strong>of</strong> the flights was within the interval 3,44 ± 0,39 minutes (03:05 minutes, 03:50 minutes).<br />

All the samples analysed which take into account time (ACT-PCT, ACT-ECT...) vs. number/ percentage <strong>of</strong><br />

flights behaved as shown in Figure 1.<br />

Figure 1.Difference between ACT and PCT <strong>of</strong> <strong>of</strong>f-block sub-process<br />

Using statistical s<strong>of</strong>tware*, an analysis <strong>of</strong> the samples was per<strong>for</strong>med. The distribution that best fit the samples<br />

whose behaviour corresponds to the previous figure was the Burr distribution. The Burr distribution is a rightskewed<br />

distribution with a flexible shape and controllable scale and location. It is frequently considered as an<br />

alternative to a Normal distribution when the data shows slight positive skewness.Figure 2 represents the statistical<br />

analysis <strong>of</strong> the previous general sample. Variable x represents the difference between ACT and PCT <strong>of</strong> OBT<br />

(minutes) and f(x) is the probability density function corresponding to the Burr distribution.<br />

* Statistical s<strong>of</strong>tware used was EasyFit (http://www.mathwave.com/)<br />

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Figure 2.Burr distribution<br />

Exercise analysis was based on the comparison <strong>of</strong> the per<strong>for</strong>mances obtained in TITAN and non TITAN<br />

Simulation scenarios. In order to compare different simulation scenarios and indicators according to the validation<br />

objectives, it was necessary to choose one measure <strong>of</strong> central tendency (mean value, µ) and one measure <strong>of</strong><br />

dispersion (standard deviation, σ).<br />

IV. Results analysis<br />

A global overview <strong>of</strong> the results could be obtained from histograms which represented the <strong>of</strong>f-block delay<br />

per<strong>for</strong>med against the percentage <strong>of</strong> flights. Figure 3 shows an example <strong>of</strong> the histograms comparing TITAN and<br />

Non TITAN <strong>for</strong> two different scenarios; Scenarios “A” are Non TITAN scenarios and scenarios “B” are TITAN<br />

scenarios.<br />

Figure 3.TITAN and Non TITAN histograms<br />

TITAN simulations always got fewer delayed flights( in the exaplaxes showed, 2,5% <strong>of</strong> delayed flighs vs 11,4%<br />

<strong>for</strong> Normal Airport Operation scenario and 9% <strong>of</strong> delayed flights vs 15,2% <strong>for</strong> Lack <strong>of</strong> Resources scenario)<br />

A. Validation objectives criteria<br />

Each exercise objective was evaluated according to the criteria shown in Table 7.<br />

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Result<br />

Passed<br />

Passed with conditions<br />

Not passed<br />

Conditions<br />

Success criteria is fulfilled <strong>for</strong> all sub-processes<br />

Severity<br />

H (High)<br />

M (Medium)<br />

L (Low)<br />

If it affects at least Off-block.<br />

If it affects at least Boarding subprocess.<br />

If affects any other sub-process<br />

different from Boarding or Offblock.<br />

None <strong>of</strong> the sub-processes fulfill the success criteria<br />

Table 7.Success criteria<br />

Severity level “High” was assigned to <strong>of</strong>f-block sub-process because it is the last turnaround sub-process and it<br />

indicates if the flight is delayed. The boarding sub-process has a higher impact on <strong>of</strong>f-block delay than the rest <strong>of</strong><br />

sub-processes, thus severity level “Medium” was assigned to it.<br />

Each exercise objective was analyzed according to these criteria. Table 8 shows the analysis <strong>of</strong> one <strong>of</strong> the<br />

exercise objectives*.<br />

Exercise Objective V2-01.E<br />

Check whether number <strong>of</strong> delayed flights [(AOBT-SOBT)>15min] decreases by 9% with TITAN with respect to<br />

Non TITAN<br />

Simulation Scenario ID<br />

GEN1AExe1 (Non TITAN) // GEN1BExe1 (TITAN)<br />

Sub-process<br />

Offblock<br />

Measurement<br />

% <strong>of</strong> flights which :<br />

ACT OBT -PCT OBT >15 min<br />

Indicator<br />

% <strong>of</strong> delayed flights with TITAN < %<br />

delayed flights with non TITAN-9%<br />

Simulation Scenario ID % <strong>of</strong> delayed flights (delay>15 minutes) Is % <strong>of</strong> delayed flights with<br />

TITAN < % delayed flights<br />

with non TITAN-9%?<br />

GEN1AExe1 7,9 %<br />

GEN1BExe1 1,4 %<br />

<br />

Result<br />

Comments<br />

Passed Number <strong>of</strong> delayed flights more than 15 minutes is reduced by 82,2%.<br />

Table 8.V2-01.E Exercise objective analysis.<br />

*Full details are presented in WP3_DEL.3.3_Validation Report. See reference 9.<br />

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B. Validation objectives assessment<br />

1. Validation objective V2-01<br />

Exercise V2-01 assessed the efficiency, predictability and flexibility per<strong>for</strong>mances <strong>of</strong> the TITAN concept under<br />

normal airport operation. Four exercise objectives were passed, three were passed with conditions and two<br />

objectives were not passed. The global conclusion <strong>for</strong> Exercise V2-01 could be considered as reached with<br />

conditions.<br />

The first not passed objective entended to reduce the standard deviation <strong>of</strong> <strong>of</strong>f-block time to 3 minutes. Even<br />

though the objective was not reached, σ was reduced by 57,2% (standard deviation was reduced from 8,1 to<br />

3,5 minutes). The TITAN concept managed to reduce σ, although the initial objective was not reached.<br />

The second <strong>of</strong> the not passed objectives was focused on checking when efficiency and predictability<br />

per<strong>for</strong>mances were maintained under unexpected events. The objective was not reached because the<br />

TITAN model worked in a different way depending on the unexpected event when comparing TITAN<br />

scenarios. Efficiency and predictability per<strong>for</strong>mances were maintained according to the success criteria<br />

only when lost passenger or increasing demand scenarios were analyzed.<br />

Objectives related to reducing the percentage <strong>of</strong> delayed flights or sub-processes and turnaround duration<br />

were reached when comparing TITAN to non TITAN scenarios. Efficiency and predictability per<strong>for</strong>mances<br />

were maintained when an unexpected event occurred when comparing TITAN to non TITAN scenarios.<br />

Deviation between the estimated and actual end times <strong>of</strong> sub-processes was only reduced in boarding and<br />

<strong>of</strong>f-block processes when introducing the TITAN concept. However, the mean value <strong>for</strong> these objective<br />

measurements improved <strong>for</strong> almost all processes. Standard deviation <strong>for</strong> the <strong>of</strong>f-block process was reduced<br />

from 8 to 7,38 minutes.<br />

Deviation between the scheduled and actual duration time <strong>of</strong> sub-processes was not reduced <strong>for</strong> most<br />

processes due to decisions taken at TITAN decision points *. However, standard deviation <strong>for</strong> the <strong>of</strong>f-block<br />

remained unchanged. Variability <strong>of</strong> sub process duration was only reduced <strong>for</strong> the boarding sub-process<br />

from 7,66 to 6,08 minutes.<br />

2. Validation objective V2-02<br />

Exercise V2-02 dealt with the assessment <strong>of</strong> the impact on turnaround efficiency, predictability and flexibility<br />

per<strong>for</strong>mances <strong>of</strong> disruptions** in a TITAN environment. Five exercise objectives were passed, three were passed<br />

with conditions and two objectives were not passed. Exercise V2-02 could be considered as reached with conditions.<br />

The first not passed objective was based on reducing standard deviation <strong>of</strong> <strong>of</strong>f-block time to 3 minutes.<br />

Despite that the objective was not reached, standard deviation was reduced when different disruptions were<br />

analyzed.For re-fuelling disruption standard deviation was reduced from 11,5 to 6,09 minutes and <strong>for</strong><br />

baggage unloading disruption it was reduced from 10,39 to 6,51 minutes.<br />

The second not passed objective was focused on checking the isolated effect <strong>of</strong> a disruption in the TITAN<br />

concept when an unexpected event occurred. The global objective was not reached. However, standard<br />

deviation <strong>of</strong> the sub-processes duration with TITAN was maintained except <strong>for</strong> the in-block sub-process.<br />

The objective <strong>of</strong> maintaining average and standard deviation <strong>of</strong> the delay time sub-processes was only<br />

reached <strong>for</strong> some sub-processes when comparing TITAN scenarios. In-block values are maintained in all<br />

scenarios. Delay average and standard deviation <strong>for</strong> baggage loading, unloading and boarding sub-process<br />

were maintained only <strong>for</strong> Late arrival scenario.<br />

Objectives related to reducing the number <strong>of</strong> delayed flights or sub-processes and turnaround durations were<br />

reached when comparing TITAN to their corresponding non TITAN scenarios. Efficiency and<br />

predictability per<strong>for</strong>mances were maintained under unexpected events. The effect <strong>of</strong> an unexpected event<br />

on efficiency and predictability per<strong>for</strong>mances was maintained under success criteria comparing different<br />

TITAN scenarios.<br />

* During TITAN simulations, a set <strong>of</strong> common decisions were followed when an alert window appeared according with the<br />

in<strong>for</strong>mation provided by the TITAN Services.<br />

** A disruption is a <strong>for</strong>ced delay in one <strong>of</strong> the sub-processess.<br />

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The rest <strong>of</strong> the objectives were passed with conditions. The first one was focused on reducing deviation between<br />

the estimated and actual end time <strong>of</strong> sub-processes. Deviation between the estimated and actual end times <strong>of</strong><br />

processes increased <strong>for</strong> most sub-processes but <strong>of</strong>f-block standard deviation was reduced( from 9,90 to 9,36<br />

minutes).Mean values <strong>of</strong> the deviation between the estimated and actual end times <strong>of</strong> processes were reduced<br />

<strong>for</strong> most sub-processes. The second objective was focused on reducing the deviation between the scheduled and<br />

actual duration <strong>of</strong> sub-processes. Deviation between the scheduled and actual duration showed different<br />

behaviour <strong>for</strong> each sub-process. Mean value deviation only decreased <strong>for</strong> baggage unloading and boarding subprocesses.<br />

Variability <strong>of</strong> process duration was only reduced <strong>for</strong> the baggage unloading sub-process. The last<br />

objective was based on reducing the variability <strong>of</strong> sub-processes durations. The objective was only reached <strong>for</strong><br />

baggage unloading sub-process.<br />

3. Validation objective V2-03<br />

Exercise V2-03 aimed to validate the application <strong>of</strong> the TITAN In<strong>for</strong>mation Services (BFIS, PFIS, AIRS and<br />

ASRS). The Exercise V2-03 global objective could be considered as reached.<br />

Turnaround durations and variability decreased with TITAN with respect to non TITAN <strong>for</strong> all the situations<br />

analyzed. BFIS and PFIS resulted the most effective TITAN Services. Turnaround duration and its<br />

variability showed the lowest values when these services were implemented. Results applying AIRS and<br />

ASRS were better than Non TITAN results. However, there were no significant differences between them.<br />

Percentage <strong>of</strong> delayed flights decreased by using TITAN Services. Results using only BFIS and PFIS were<br />

quite similar to the ones obtained when all TITAN services were implemented. They provided a reduction<br />

<strong>of</strong> 94,6% <strong>of</strong> delayed flights. By applying only AIRS and ASRS, reduction <strong>of</strong> the percentage <strong>of</strong> delayed<br />

flights was 38,6%. Boarding and <strong>of</strong>f-block sub-processes showed more differences when different TITAN<br />

Services were implemented. For these processes, the delay mean value and standard deviation were greater<br />

when only AIRS and ASRS were implemented.<br />

There were not many differences between scenarios when comparing delayed time <strong>of</strong> sub-processes.<br />

Differences in boarding were due to the decisions taken during the TITAN simulation. Mean values <strong>of</strong> subprocesses<br />

duration were quite similar and standard deviation values were reduced when TITAN services<br />

were implemented( standard deviation was reduced from 7,22 to 5,46 min. <strong>for</strong> baggage loading and from<br />

15,27 to 6,01<strong>for</strong> boarding process when all TITAN Services are implemented) . Results were similar when<br />

all TITAN Services were implemented and when only some <strong>of</strong> TITAN Services were implemented.<br />

4. Validation objective V2-04<br />

Exercise objectives V2-04 dealt with assessing cost effectiveness. This exercise checked if certain level <strong>of</strong><br />

turnaround efficiency (assessed through delays) could be maintained under normal airport operation while reducing<br />

the number <strong>of</strong> resources. V2-04 objective compared two TITAN scenarios, one <strong>of</strong> them with a reduction <strong>of</strong> airport<br />

resources. The global objective V2-04 was not reached. It meant that TITAN Concept <strong>of</strong> Operations didn’t make up<br />

<strong>for</strong> resources reduction.<br />

Standard deviation <strong>of</strong> the turnaround sub-processes delay time with TITAN was not maintained <strong>for</strong> any process.<br />

The percentage <strong>of</strong> delayed flights was not maintained when reducing the number <strong>of</strong> resources by a 20%; it increased<br />

by 79,7%.<br />

C. KPI analysis<br />

Next table shows some <strong>of</strong> the KPI analyzed <strong>for</strong> V2-01 Validation objective. This analysis was done <strong>for</strong> all KPI<br />

<strong>of</strong> each Validation objective 9 .<br />

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Measurement //<br />

(unit)<br />

Non<br />

TITAN<br />

TITAN<br />

Non TITAN<br />

TITAN<br />

Non<br />

TITAN<br />

TITAN<br />

Non<br />

TITAN<br />

TITAN<br />

Non<br />

TITAN<br />

TITAN<br />

Normal<br />

operation<br />

Late<br />

passenger<br />

Increasing<br />

demand<br />

Late arrival<br />

Lack<br />

resources<br />

<strong>of</strong><br />

KPI<br />

Total Delay (Off-<br />

Block)<br />

Accommodate<br />

scheduled<br />

changes<br />

without<br />

increasing<br />

delays<br />

ACT-PCT //<br />

(minutes)<br />

ACT-ECT //<br />

(minutes)<br />

3,44 0,79 14,89 1,71 7,23 0,84 6,09 3,25 4,54 2,70<br />

1,18 -1,4 12,63 -0,55 4,60 -1,81 -0,51 -3,41 2,28 -1,04<br />

Table 9.KPI results<br />

Global results from the four validation exercises KPI are showed below:<br />

Variability <strong>of</strong> ETTT: Reduced with TITAN.(From 3,95 to 0,84 <strong>for</strong> V2-01 objective and Increasing demand<br />

scenario)<br />

Off Block punctuality: Increased with TITAN.( From 54,69 to 97,57 <strong>for</strong> Late passenger scenario and V2-03<br />

objective)<br />

Total Delay (Off-Block): Reduced with TITAN.( From 7,36 to 3,40 <strong>for</strong> a disruption in fuelling <strong>for</strong> V2-03<br />

objective)<br />

Accommodate scheduled changes without increasing delays: Reduced with TITAN. .( From 5,10 to 1,13 <strong>for</strong><br />

a disruption in fuelling <strong>for</strong> V2-03 objective)<br />

Recovery delay factor when lost passenger: Increased with TITAN. ( A 34,65% <strong>for</strong> V2-02 objective)<br />

Recovery delay factor upon gate reallocation: Increased with TITAN. ( A 54,91% <strong>for</strong> V2-04 objective)<br />

Recovery delay factor when unavailability <strong>of</strong> a service is detected: Increased with TITAN. ( A 73,56% <strong>for</strong><br />

V2-04 objective)<br />

V. Conclusion<br />

The main conclusions <strong>for</strong> validation activities can be summarized as follows:<br />

As a global result, 2 exercises could be considered as passed with conditions, 1 exercise passed and 1<br />

exercise not passed.<br />

o<br />

o<br />

o<br />

o<br />

Percentage <strong>of</strong> delayed flights, mean values <strong>of</strong> sub-processes delay, number <strong>of</strong> delayed subprocesses<br />

and turnaround durations were always improved when introducing TITAN Concept <strong>of</strong><br />

Operations.<br />

Standard deviation value <strong>of</strong> OBT (ACT-PCT) was always reduced when comparing TITAN<br />

simulation scenario to its corresponding Non TITAN simulation scenario although the objective to<br />

achieve 3 minutes was not reached.<br />

Standard deviation <strong>of</strong> estimated indicators was worse than standard deviation <strong>of</strong> actual indicators<br />

<strong>for</strong> the same simulation scenario.<br />

Not passed objectives were focused on evaluating if per<strong>for</strong>mances were maintained under different<br />

situations comparing different TITAN simulation scenarios. Some <strong>of</strong> them could be considered as<br />

passed using less stringent success criteria.<br />

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<strong>AIAA</strong>-<strong>Pegasus</strong> Student Conference


o<br />

TITAN Services BFIS and PFIS resulted to be more effective than AIRS and ASRS despite AIRS<br />

and ASRS provided more in<strong>for</strong>mation.<br />

All KPIs analysed <strong>for</strong> each Validation objective were improved when TITAN was implemented.<br />

Regarding the four KPA considered <strong>for</strong> TITAN project, the following conclusions can be obtained:<br />

Predictability increased when TITAN Concept <strong>of</strong> Operations was implemented. However, the<br />

per<strong>for</strong>mance objective based on reducing the standard deviation up to 3 minutes was not reached.<br />

<br />

<br />

<br />

Efficiency increased when TITAN was implemented due to the reduction <strong>of</strong> delayed flights by<br />

9%. The number <strong>of</strong> delayed flights decreased even more than a 9%.<br />

Flexibility increased when TITAN was implemented due to better compliance with Efficiency and<br />

Predictability in case <strong>of</strong> unexpected events.<br />

Cost effectiveness regarding operational costs reduction was not directly assessed. However, an<br />

improvement in predictability, efficiency and flexibility should result in a cost-effectiveness<br />

indirect improvement.<br />

Validation activities <strong>of</strong> the V2 phase finalized with the analysis and conclusions summarized above. TITAN<br />

Consortium considered that the operational concept accomplished the expectations. Next phases <strong>of</strong> the TITAN<br />

project, including a Decision Tool <strong>for</strong> airlines and a Cost Benefit Analysis, went on after the end <strong>of</strong> validation<br />

activities.<br />

Acknowledgments<br />

The author would like to acknowledge the colleagues from CRIDA, specially to N.Suárez,E.Puntero and<br />

I.Navarro <strong>for</strong> revision and support; and all partners from the TITAN Consortium <strong>for</strong> the excellent work carried out.<br />

References<br />

1 EUROCONTROL.Per<strong>for</strong>mance Review Report.2006. http://www.eurocontrol.int/<br />

2 TITAN Consortium, WP1_DEL.1.1_Analysis <strong>of</strong> the current situation.May 2010. http://www.titanproject.eu/library/titan/TITAN_WP1_SLO_DEL_01_v1.0_Analysis_<strong>of</strong>_the_current_situation.pdf<br />

3 TITAN Consortium, WP1_DEL.1.4_TITAN Operation Concept document( Issue 1&2).November 2012. http://www.titanproject.eu/library/titan/TITAN_WP1_INE_DEL_04_v1.0_TITAN_Operational_Concept_Issue2.pdf<br />

4 EUROCONTROL, “Airport CDM Implementation. The Manual” V3.1. July 2010. http://www.eurocdm.org/library/cdm_ocd.pdf<br />

5<br />

EUROCONTROL SJU SWIM. http://www.sesarju.eu/programme/highlights/swim-atm-intranet<br />

6 EUROCONTROL, The European Operational Concept Validation Methodology( E-OCVM), V3.February 2010.<br />

http://www.eurocontrol.int/val<strong>for</strong>/gallery/content/public/docs/E-OCVM3%20Vol%20II%20WebRelease.pdf<br />

7 TITAN Consortium, WP2_DEL.2.7_TITAN executable model. http://www.titan-project.eu/index.php/library<br />

8 TITAN Consortium, WP1_DEL.1.3_Per<strong>for</strong>mance Framework.October 2010. http://www.titanproject.eu/library/titan/TITAN_WP1_ISD_DEL_03_v1.0_Per<strong>for</strong>mance_framework.pdf<br />

9 TITAN Consortium, WP3_DEL.3.3_Validation Report.July 2012. http://www.titanproject.eu/library/titan/TITAN_WP3_AEN_DEL_04_v1.0_Validation_Report.pdf<br />

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