EEC SEE 2006 002 - Eurocontrol · One of the keys to success of flight prioritisation is to determine the best time to switch from private priority to network priority. If the required

Flight Prioritisation Prototype

Concept: Flight Prioritisation

& Operational Process: Airport Auto-Regulation

EEC/SEE/2006/002


Authors: Murillo A. (NeoSYS) Carlier S. (NeoSYS) NeoSYS 7, rue du Théâtre 91300 MASSY http://www.neosys.fr

EUROCONTROL Project Supervisor Jean-Pierre FLORENT – [email protected] EEC Note: EEC/SEE/2006/002

REPORT DOCUMENTATION PAGE

Reference: EEC Note N° EEC/SEE/2006/002

Security Classification: Unclassified

Originator: EEC - SEE (Society -Environment-Economy)

Originator (Corporate Author) Name/Location: EUROCONTROL Experimental Centre Centre de Bois des Bordes B.P.15 F - 91222 Brétigny-sur-Orge CEDEX FRANCE Telephone : +33 (0)1 69 88 75 00

Sponsor: EUROCONTROL project EEC/SEE

Sponsor (Contract Authority) Name/Location: EUROCONTROL Agency Rue de la Fusée, 96 B -1130 BRUXELLES Telephone : +32 2 729 9011 Internet : www.eurocontrol.int

TITLE: FLIGHT PRIORITISATION PROTOTYPE

Concept: Flight Prioritisation

Operational Process: Airport Auto-Regulation

Author Florent J.P

Murillo A. (NeoSYS) Carlier S. (NeoSYS)

Date 06/2006

Pages vii + 26

Figures 13

Tables 0

Annex 0

References 4

Project SEE-APPRO-V.0-0

Task No. Sponsor Period 2006

Distribution Statement: (a) Controlled by: Head of SEE (b) Special Limitations: None (c) Copy to NTIS: YES/NO

Descriptors (keywords): Users Preferences, Airlines Prioritisation, Airport Crisis, Regulation, Auto-Regulation, Average Delay for departure flights, Demand & Capacity, planned & real time criteria, Tests & Trials

Abstract: This note describes a EUROCONTROL prototype specification to establish a flight prioritisation to order and select preferred flights for departure at the airport level under adverse conditions. The auto-regulation makes a balance between the average delay for the departure flights and the number of delayed flights. The system describes the way allowing airlines to re-issue the delayed flights.


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Table of Content Summary........................................................................vi 1 Introduction ............................................................... 1

1.1 Purpose ........................................................................................................1 1.2 Airport Delays ...............................................................................................1 1.3 Actors and Priority Management...................................................................3 1.4 Airport Priority Management Today ..............................................................4

1.4.1 In Normal Conditions .............................................................................5 1.4.2 In Adverse Conditions............................................................................5

2 Flight Prioritisation..................................................... 6 2.1 Airline Priority Management..........................................................................6

2.1.1 Definition of the Flight Economical Weight ............................................6 2.1.2 FEW in Operation ..................................................................................8 2.1.3 Expected Benefits..................................................................................8 2.1.4 Expected Impacts on Actors ................................................................10

2.2 Priority Management in Adverse Conditions ...............................................11 2.2.1 Definition of the Priority in Adverse Conditions....................................11 2.2.2 PAC in Operation.................................................................................11 2.2.3 Expected Benefits................................................................................11 2.2.4 Expected Impacts on Actors ................................................................11

3 Implementation and Evaluation Guidelines ............. 12 3.1 Flight Prioritisation in Operation..................................................................12

3.1.1 FEW.....................................................................................................12 3.1.1.1 Default FEW Indicator ......................................................................12 3.1.1.2 FEW Assessing Tool........................................................................12 3.1.1.3 Operational process .........................................................................13

3.1.2 PAC .....................................................................................................14 3.1.2.1 Criteria .............................................................................................14 3.1.2.2 Suggested Formula..........................................................................14 3.1.2.3 PAC Editor .......................................................................................17 3.1.2.4 Airport Auto-Regulation....................................................................18

3.2 Concept Evaluation.....................................................................................20 3.2.1 FEW.....................................................................................................20

3.2.1.1 KPI Definition ...................................................................................20 3.2.1.2 Simulations.......................................................................................20

3.2.2 PAC .....................................................................................................20 3.2.2.1 KPI Definition ...................................................................................20 3.2.2.2 Simulations.......................................................................................21 3.2.2.3 Auto-Regulation Process .................................................................21

4 Conclusion .............................................................. 25

Glossary of Terms and Abbreviations .......................... 26



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List of Figures Figure 1: Airport Delays ..............................................................................................1 Figure 2: Share of Airport & En-route Delay................................................................2 Figure 3: Departure punctuality and underlying delay drivers .....................................3 Figure 4: Primary Departure Delay Causes for 2005 ..................................................4 Figure 5: FEW – Decision Criteria...............................................................................7 Figure 6: Potential time benefits..................................................................................9 Figure 7: FEW – Delay Absorption (Departure Sequence) .......................................13 Figure 8: Passengers Flight Prioritisation..................................................................16 Figure 9: Cargo Flight Prioritisation...........................................................................17 Figure 10: Priority Formula Editor .............................................................................18 Figure 11: Airport Crisis & Regulation .......................................................................22 Figure 12: Auto-Regulation Processes......................................................................23 Figure 13: Airline Re-issues a Cancelled Flight.........................................................24

References EUROCONTROL Collaborative Decision Making – Malpensa – WP2 Nov.2003 TALC - Tube Advanced Lane Control – Concept Dec.2004 Challenges to Growth 2004 Report Dec. 2004 Performance Review Report 2005 Apr. 2006



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Summary

The air traffic system actors have different interests with respect to performance. One way to improve performance is flight prioritisation, e.g., runway throughput optimised by selecting flights for departure according to their wake vortex category. Each and every actor has specific performance criteria. We can distinguish network and private criteria: network criteria improve the efficiency of the global system; private criteria improve the performance of a particular actor. One of the keys to success of flight prioritisation is to determine the best time to switch from private priority to network priority. If the required network performance is satisfied, actors can favour private criteria, and hence improve private performance. This document proposes to evaluate the two following priority indicators:

• Flight Economical Weight (FEW) which is a priority indicator for a given airline, and

• Priority in Adverse Conditions (PAC), which is a global indicator. These two indicators are based on different criteria, and are key to the prioritisation process. The flight prioritisation principle is to give priority to the flight with the highest priority indicator (FEW or PAC). The FEW characteristics are:

• The FEW is airline provided data. • The FEW is used in sequencing operation. • When all flights of an airline receive the same highest value of FEW, the

prioritisation between flights is of no consequence. • The FEW defines a priority between flights of one airline but it could be

possible to define the same FEW for an alliance. • In sequencing, the prioritisation process does not delay a flight but allows

selecting one flight from several flights waiting for a clearance. • The prioritisation between flights can be applied during the gate-to-gate

operations and the interest is to share FEW status with all concerned partners (ADEP to ADES).

The PAC characteristics are:

• The PAC is a data defined for all flights from any airline. • The PAC is used when the air traffic system can no longer satisfy the traffic

demand. • The operational process associated with the PAC is the airport auto-

regulation. • The airport auto-regulation consists of determining the number of flights that

can depart according to an average agreed delay. • The selection of flights for departure will be based on the flight priority.



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A prioritisation system will be valuable: • The airport partners will manage the traffic regulation (average delay) on the

airport. • The proposed prototype selects flights for departure according to the

passengers interest (automatically) and the partner’s preferences (manually). • The ATFM regulation will have less impact on the concerned traffic. • The traffic planning and the 4D trajectory will be improved for the air side

traffic. • An automatic link between traffic demand and airport capacity will allow an

earlier and better planning of the next departures. • This proactive process will improve the planning of the expected traffic and

resources on both ground side and air side. • The punctuality will be improved and the favoured flights on departure will

arrive closer to their airport slots at destination.


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1 Introduction

1.1 Purpose

The flight prioritisation concept comes within the SEE (Society Environment Economy) framework by taking into account:

• The interest of the passengers in terms of facilities, delays and satisfaction, • The interest of the airlines in terms of cost, punctuality, flexibility and client

satisfaction, • The interest of the environment in terms of fuel consumption and emissions.

The purpose of the flight prioritisation concept is to come to a consensus between all the stakeholders satisfying these different interests. Passengers flying for business with meetings at their destination expect a good punctuality and fear delays. Delays are costly to the airlines, since the crews and fleet management are a key budget heading. The respect of the schedule is the first step for efficient crew and fleet management, and therefore airlines are keen to know in advance the flights to re-schedule. At the airport level, knowing the real demand and the new schedule in advance will avoid supplementary aircraft on taxi ways or in stack holdings, and will prevent early start-up clearances which generate useless fuel consumption.

1.2 Airport Delays

During 2005 the ATM delays attributed to airports rose considerably and now constitute around 50% of all ATM delays. These delays turn airports into a critical constraining factor for achieving European air traffic growth (refer to the Challenges to Growth1 study).

Figure 1: Airport Delays

European air traffic is estimated to grow by a factor of 2.2 over the next 20 years, which makes improving airport efficiency a major objective.

1 Challenges to Growth 2004 Report, EUROCONTROL, Dec. 2004



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Figure 2: Share of Airport & En-route Delay

The EUROCONTROL Performance Review Report 20052 identified 3 main categories of pre-departure delays:

• Local turnaround delays are primary delays caused by the actors directly involved in the turn-round process, e.g. airlines (technical, boarding, check-in, etc.), airports (equipment failure, security, etc.) or other parties such as local ATC (only minor contribution).

• ATFM delays are also primary delays which occur when traffic demand exceeds available ATM en route capacity (En-route ATFM delays) or at airports (Airport ATFM delays).

• Reactionary delays are secondary delays caused by primary delays (local turn-round and ATFM delays) in the course of earlier flight legs which cannot be recuperated during turn-round (i.e. when the aircraft is at the stand). Due to the interconnected nature of the air transport system, long primary delays can spread through the ATM network until the end of the same operational day.

2 Performance Review Report 2005, Performance Review Commission, EUROCONTROL, Apr. 2006



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Figure 3: Departure punctuality and underlying delay drivers

The Figure 3 shows that nearly half of the delays are reactionary delays. This means in practice that overall punctuality is expected to improve by carefully prioritising amongst the departing flights.

1.3 Actors and Priority Management

An airport is a complex mix of different partners and each and every partner may generate delays.



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Figure 4: Primary Departure Delay Causes for 2005

By weighting their constraints and prioritisations, each actor manages these delays and congestions differently – for example:

• Tower Optimization: Optimal runway use during peak hours Constraint: Runway throughput Criterion: ‘Type of aircraft’ • Airport authority Optimization: Best flight punctuality

Constraint: Airport slot allocation to achieve punctuality and avoid bottleneck on the airport

Criterion: ‘Target Landing Time’ • Airline Optimization: Minimum additional costs Constraint: Favoured flights inducing a high additional cost in case of delays Criterion: ‘Flight Economical Weight’

These criteria can sometimes compete. However, an efficient airport system depends on how these priorities are managed.

1.4 Airport Priority Management Today

By observing the state of the art at major airports, we identify two distinct situations: • Normal conditions: in normal condition, the airport capacity matches the traffic

demand. • Adverse conditions: theses conditions occur due to several reasons such as

bad weather, strikes, technical problems, etc. Adverse conditions mean that airport capacity does not match the demand in landing/take-off. When unusually large delays occur a non-negligible number of flights might have to be cancelled.



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1.4.1 In Normal Conditions

Normal conditions are defined as the conditions on an airport when the global delay is less than a specified delay threshold agreed by the actors. In normal conditions, each actor manages their priorities independently. For airline operations, the highest priority flights should not be delayed. The airline operator will try to negotiate privileged apron location, reinforce handling and catering staff, and eventually re-negotiate their take off slots for these flights. On the other hand, the air traffic controllers will manage the flights so that the traffic on taxiways remains fluid and the runway throughput satisfies the demand.

1.4.2 In Adverse Conditions

Adverse conditions are defined as the conditions on an airport when the global delay is greater than a specified delay threshold agreed by the actors. In adverse conditions the CFMU manages the airspace capacity and the traffic demand through regulations that does not make prioritisation between flights. When unforeseen adverse conditions occur, a relative disorganisation governs the airport. Usually the flight schedule is maintained, but due to reduced capacity, delays accumulate and can become very important, more than 90 min for departure flights3. Maintaining all flights can become very expensive for the airlines and disastrous for the passengers when the delays have important consequences. During major crises (like strikes) flight cancellations are inevitable. When adverse conditions are anticipated to occur, the main airport partners are gathered in a ‘Crisis Management Committee’, e.g., airline operations, air traffic control, airport authority, ground handling and meteorology representatives. The committee prioritises amongst the flights, i.e. which flights have the highest priority and which flights that can be delayed or even cancelled. The final departure lists are then distributed to the airline operations representatives in order for them to act upon. When the adverse conditions can be predicted, the ‘Crisis Management Committee’ meets in advance to review the day’s planning, thus allowing airlines to arrange for their passengers in the best way possible (rescheduling, use of alternative connections, prevent passengers from cancelled flights coming to the airport…). However for unpredictable adverse conditions, a major issue is that the committee often meets while the crisis is already in full swing. This lack of foresightedness and anticipation seriously adds to the confusion and diminishes the global airport efficiency.

3 Zaventem, 2001



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2 Flight Prioritisation We need to define a priority indicator which will determine which flights have priority. This indicator will be different depending on the situation (normal or adverse). We will focus on:

• the Flight Economical Weight (FEW) which is a priority indicator for a given airline, and

• the Priority in Adverse Conditions (PAC), which is a global indicator. The purpose of this section is to explain these indicators and to suggest how to use them in the air transport system processes in order to improve the system efficiency.

2.1 Airline Priority Management

2.1.1 Definition of the Flight Economical Weight

The cost of supplementary delays varies greatly between flights when these delays jeopardize the network connectivity or the arrival time when the destination airport has a curfew. External conditions or real time conditions mean that added delays lead to supplementary costs like the passengers’ compensation and the disruption in the fleet and crews management. The quality of service and the passengers’ satisfaction4 drive the airline to find a better solution favouring this kind of flight by giving it a priority. In order to share a flight priority indicator with all the actors involved in a flight, airlines (alliances) need a data element that gives precedence to the preferred flights. We introduce the Flight Economical Weight (FEW) as an economical data. The flights with the highest FEW will have priority with respect to the airline (alliance). FEW is computed based on flight information, e.g., number of passengers or crew and fleet management and some confidential information. The economical value of a flight can be known in advance and planned by the airline. But, in real time, extra delays can change the cost of a flight. FEW is a dynamic data, which could be kept up to date with live flight information. The FEW indicator has to reflect the planned and the real time part of the priority but also can be a criterion for automatic decision.

• FEW planned Low and Normal Priority Level The planned value distinguishes flights in two categories: low and normal priority. Using these different values, actors can give precedence between flights of an airline in normal conditions.

• FEW Real Time

High Priority Level Flights having low and normal priority receive high priority level when faced with extra delays or problems. High priority scores the flight precedence in the sequencing operations and starts automatic decisions for several actors like:

4 Average delay per passenger



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o Handling agent improving sequencing for preferred flights in de-icing, refuelling, etc., operations and SLA enter in application,

o OCC5 trying to solve the problem by obtaining a new route, o Eye catcher for pilot and crew in order to accelerate the departure, o Tower taking the flight precedence in their taxi way control and clearance

deliveries, o En route operators with the departure and arrival sequences: STAR and

SID allocation, o CFMU trying a slot improvement.

Highest Priority Level The highest priority level corresponds to the events in which the OCC contacts different operators in order to obtain better conditions for a flight. Despite all the preceding actions, the highest priority level can launch automatic decisions like:

o Handling agent increases the workers team for the flight preparation, Performs swapping between flights in sequencing (de-icing, refuelling…),

o CFMU tries to perform a slot swapping between fights, Slot Swapping: Exchange of the slot of one flight with the slot of another one, Slot substitution upon cancellation: Use slot of a cancelled flight by another flight, Slot shifting: Degradation of a flight slot to the benefit of a delayed flight.

The FEW incremental values are summarized in Figure 5.

FEW Priority Indicator

2. Real Time

20 high 30 highest

1. Planned

00 low 10 normal

FEW & Prioritisation

Flights Ordering according to their priority indicator during sequence operations :

arrival, holding stack, landing, in-blockstand allocation

turn-around processes departure, push-back, de-icing, line-up

ATFM slot allocation, slot swappingSID or STAR allocation

Airline Priority Concept concerns Airport and ATC and CFMU Priority Status concerns flights of an Airline (Alliance?)

FEW Priority Indicator

2. Real Time

20 high 30 highest

1. Planned

00 low 10 normal

FEW & Prioritisation

Flights Ordering according to their priority indicator during sequence operations :

arrival, holding stack, landing, in-blockstand allocation

turn-around processes departure, push-back, de-icing, line-up

ATFM slot allocation, slot swappingSID or STAR allocation

Airline Priority Concept concerns Airport and ATC and CFMU Priority Status concerns flights of an Airline (Alliance?)

Figure 5: FEW – Decision Criteria

Each and every flight is assigned a FEW. Hence it can be considered as a flight plan data. And as a flight plan data it can be transmitted to any ATS actor. In addition, since the flight plan does not necessarily guarantee the information update to all the concerned actors, FEW could be a FUM or DPI data and so kept up to date thanks to transmission of these messages. Note that a FEW update should not trigger the messages, in order to avoid excessive message exchange.

5 Operations Control Centre



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2.1.2 FEW in Operation

Basically, the priority management in normal conditions consists in swapping between flights of an airline. The swapping gives priority in sequencing operations to the flight with the highest FEW amongst flights waiting to enter in the same sequence or waiting for the same clearance. In any case, each partner is free to consider the airline priority. Its own priority or constraints (safety, equality of treatment, efficiency…) shall be served first and can depend on external conditions. This process replaces the rule ‘first come, first served’ on a waiting point and instead the rule ‘highest priority, first served’ is used. This concept can be applied at different points in the ATM system: airport operations, ATC, CFMU regulations; and in diverse sequencing operations:

• Holding stack, • Vectoring, • Landing, • Taxi-in control, • Stand allocation, • Turn-round process, • Departure, • Push back, • De-icing, • Taxi-out control, • Line-up, • ATFM slot allocation, • SID or STAR allocation, • Conflict resolution, re-routing, direct in en-route phase.

2.1.3 Expected Benefits

Below is an example of a complete airport airside process: For each process operation, we assess the potential time benefit which corresponds either to the difference between minimum and maximum time required to perform the task, or to the operation rotation time. The rotation time is the duration between two clearances or two calls starting the same operation (for instance the duration between two push back clearances given by the tower controller to two consecutive flights, and not the time required to perform the push back). Note that in a swapping operation a flight can win one or several rotation times according the difference of the ordering between the two flights. Obviously the real benefits gained with a prioritisation process will be less than the total potential benefits. The values are used as a first evaluation just to give an idea how much time can be gained.



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Figure 6: Potential time benefits

• En Route Operations Several input orders from the controller can favour or penalise a flight: direct order, orders used in conflict resolution, vectoring process, choice of a SID. In a conflict resolution, often a flight is penalised by a change of level or heading or with a lower speed. These input orders can be reserved for the flights with a lower FEW. The vectoring process is executed at the arrival to assure a better throughput on the runway. But all the flights are not put in a vectoring phase: the controller can choose the lower FEW. The choice of a SID can add until 10 minutes to the flight route when the chosen SID is in opposite direction of the flight route. It would be better to avoid that for higher FEW and to pass a turn in the take-off sequence. • Landing The geographical position of the stand gives an average time to execute the taxi-in and the taxi-out operations. The choice of the stand position can favour or penalise a flight. • ATFM Slot According to the first day trials ‘Amsterdam’ performed by the CFMU and KLM to address slot swapping, the average time saved by the favoured flight is about 50 minutes. And the benefit of the swap itself is nothing compared to the savings the airline has in terms of connectivity of its network.



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• Turn-Around In case of delays, the turn-around processes can be accelerated by SLA (Service Level Agreements) between the handling agent and the airline. Workers can be added to perform a job or the job can be reduced to spare time. But also airline saves time with the equipment of the stand. A de-icing on stand is shorter than a de-icing on a remote bay (5 minute time difference). A remote operation takes a supplementary time on the taxi way (2 minutes more). • Control Crossing on taxi way or on runway takes time (waiting time) and penalises flights. High FEW can be favoured by preference or by the choice of the taxi way. Taxi time in peak hours can be multiplied by two or three. In this case, the place in the push back sequence can change the place in the line-up sequence. (Line-up rotation 1’20 x number of saved places). • Take-off The holding position can modify the sequence for the line up clearance. When it is possible the controller can favour higher FEW.

These potential benefits are estimated for normal conditions and during peak hours when delays start to grow. From this example, we see that a flight could gain time at several sequencing operations from its planned schedule. This time saved represents a cost saving for the airline but also satisfaction for the passengers. At first glance, we can expect significant benefits from a prioritisation process.

2.1.4 Expected Impacts on Actors

In order to improve a flight situation, an airline calls the concerned operator: tower for departure, CFMU for ATFM slot and re-routing, handling agent, sector in airside operations and airport for stand allocation. A priority indicator shared between all the actors will avoid phone communications. Usually, flights are ordered according to several criteria and the controller takes the first flight in the list to perform his job. The priority status of a flight (FEW) is used like ordering criteria between two or more flights when these flights are waiting for the same operation. The idea is to integrate the FEW in the operational tools. If the flight lists that are presented to the controllers integrate the FEW, this process will be transparent to the controllers. They will not need to change their working habits.



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2.2 Priority Management in Adverse Conditions

2.2.1 Definition of the Priority in Adverse Conditions

The Priority in Adverse Conditions (PAC) is a new data element that we define as a priority indicator amongst all flights managed by an airport during adverse conditions. This priority takes into account diverse flight information and also destination airport information. PAC is calculated the same way for any flight from any airline.

2.2.2 PAC in Operation

Priority management in adverse conditions consists in designating the flights that will not be able to take off with an acceptable delay. PAC values help to determine the departing flights list. The airlines with flights that are not on that list will be encouraged either to reschedule a new EOBT, to regroup the flight with others or to cancel the flight.

2.2.3 Expected Benefits

Benefits are expected with respect to passengers, airlines and environment. Concerning passengers, better satisfaction is expected thanks to early actions taken by the airline. The airlines are assumed to manage their flights more efficiently and so reduce the costs. As to environment issues, better anticipation will lead to emissions reduction. The Crisis Management Committee will be able to take better decisions thanks to tools integrating the PAC. Their reactivity will be faster, the anticipation better. A better balance between the airport capacity and the airport demand will lead to a more accurate planning and a better flight management. A benefit analysis can be done from a network point of view (better planning, best use of resources, safety improvement, regulation improvement, environment, etc.) but also from a private perspective (profit and loss estimated for departure flights and for delayed flights, from a network point of view and from an airline point of view). It will be interesting to measure in a cost/benefit analysis the link between the interests of the passengers as described here and the real cost of a flight for an airline.

2.2.4 Expected Impacts on Actors

Priority management in adverse conditions using PAC will require new tools integrating the flight priority. Such tools will assist the airport partners in their decision making. Actors will have to develop collaborative and automatic procedures. Airport auto-regulation is a real collaborative decision making process where actors like ACC, TWR, FMP, CFMU, Airport and handling agents try to adapt the capacity to the demand and where airlines try to adapt the demand to the capacity. Automatic procedures mean less phone communications and more reactive process to find a solution lightening the workload of the operators.


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3 Implementation and Evaluation Guidelines This chapter gives guidelines for the flight prioritisation concept implementation and evaluation in terms of:

• Priority formulation, • Tools required, • Operational procedures, • Key Performance Indicators, • Simulations.

3.1 Flight Prioritisation in Operation

3.1.1 FEW

3.1.1.1 Default FEW Indicator The Flight Economical Weight is an airline-provided (or alliance) data element. In case no partnership is agreed with an airline for a concept evaluation study, we give in this section a really basic approach which could be used as a FEW indicator for prototype testing and process evaluation purposes. The following table gives the planned FEW values according to the number of passengers.

Passengers Number Priority FEW

< 85 Low 0 > 85 Normal 1

Some real time flight events can change the FEW:

Flight Events Priority FEW6 Flight Delay > 15’ High 2 Delay > 10’ & Transit Pax High 2 Delay > 20’ + Curfew Highest 3 Flying Time > 2H & Curfew Highest 3 Delay > 20’ & Transit Pax Highest 3 Shuttle Current level – 1 FEW – 1 Accumulated Delay > 15’ Current level + 1 FEW + 1

3.1.1.2 FEW Assessing Tool The best way to check whether the FEWs given to flights match the airline priority is to compare the two flight lists: the original flight list and the resulting flight list after FEWs have been taken into account.

6 FEW value : maximum = 3 & minimum = 0



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Requirements: • A FEW assessing tool shall present the two flight lists.

3.1.1.3 Operational process

Figure 7: FEW – Delay Absorption (Departure Sequence)

Over many movements, the minutes saved add up to create additional capacity and reduce delays.

Example 1: Push-back Sequence

For external reasons the TWR controller is ready to give the departure clearance to a flight at 12h02’.At this time Flight A and flight B are ready for push-back. In our example: first flight A at 12h00 and then flight B at 12h01’.At 12h01’ the departure manager has two flights ready to go.The DMAN tool orders flight B before flight A according to the flights FEW.The TWR controller gives the first clearance to flight B.

Example 2: Line-up Clearance

The airway control is ready to send a line-up clearance at 12h15’.At this time two flights are waiting for line-up.Flight A since 12h14’ and flight B since 12h15’At 12h15’ the departure manager has two waiting flights at the holding points.The DMAN tool orders flight B before flight A according to the flights FEW.The TWR controller gives the line-up clearance to flight B.

When several flights are waiting for :

Example 1: Push-back Sequence

For external reasons the TWR controller is ready to give the departure clearance to a flight at 12h02’.At this time Flight A and flight B are ready for push-back. In our example: first flight A at 12h00 and then flight B at 12h01’.At 12h01’ the departure manager has two flights ready to go.The DMAN tool orders flight B before flight A according to the flights FEW.The TWR controller gives the first clearance to flight B.

Example 2: Line-up Clearance

The airway control is ready to send a line-up clearance at 12h15’.At this time two flights are waiting for line-up.Flight A since 12h14’ and flight B since 12h15’At 12h15’ the departure manager has two waiting flights at the holding points.The DMAN tool orders flight B before flight A according to the flights FEW.The TWR controller gives the line-up clearance to flight B.

When several flights are waiting for :



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3.1.2 PAC

3.1.2.1 Criteria A criterion candidate for the PAC is a verifiable data provided by different actors.

Id Name Value Origin

PN Number of passengers Airline CN Number of connections at destination Airline CF Curfew at destination 0 or 1 Airport LF Last Flight of the day7 0 or 1 Traffic FT Flying Time in hours FPL AD Accumulated Delay in minutes TWR SF Shuttle8 0 or 1 Airport PF Private Flight 0 or 1 Airline EF Event Flight 0 or 1 Airport

The prioritisation process shall also consider the flights with Special Status: Hospital, Emergency, HUM, SAR, STATE, HEAD. These flights will have greater priority.

3.1.2.2 Suggested Formula

3.1.2.2.1 Criteria Combination Principle The following example shows how different criteria can be combined together to give a priority. We choose the number of passengers as the priority indicator unit. This number will be weighted by the other criteria. The two criteria we take into account are in this example:

• The number of passengers (PN) • The number of connections at destination (CN)

A flight with several connections at destination has more priority than a flight without any connection, these 2 flights having the same number of passengers on board. In order to adjust the CN weight in relation to PN, we apply a correcting factor N1 %.

PAC = PN (1 + CN * N1%) And if we define: CNV = CN * N1%

PAC = PN (1 + CNV)

7 When LF= 1 then SF= 0 8 Several flights per day for the same destination



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We obtain the following results for 2 flights with the same number of passengers, but one with several connections at destination:

Flight A Flight B PN 150 150 CN 0 8

PAC with N1 = 6 % 150 222 PAC with N1 = 1 % 150 162

The same process can be applied to all the criteria. In the next two sections we suggest a formula for passenger flights and one for cargo flights.

3.1.2.2.2 Suggested Formula for Passenger Flights We can distinguish between the criteria those favouring the flight priority and those penalizing it. The favouring criteria are:

• Number of Passengers, • Number of Connections, • Curfew, • Last Flight, • Flying Time, • Accumulated Delay.

The penalizing criteria are:

• Shuttle, • Private, • Event.

We obtain the formula:

PN (1 + CNV + CFV + LFV + FTV + ADV) PAC = ------------------------------------------

(1 + SFV + PFV + EFV)

with the weighted criteria:

CNV = CN * N1% CFV = CF * N2% LFV = LF * N3% FTV = FT * N4% ADV = AD * N5% SFV = SF * N6% PFV = PF * N7% EFV = EF * N8%



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The Nx % correcting factors allow airport actors adjusting the priority according to their preferences or to the kind of traffic.

Figure 8: Passengers Flight Prioritisation

3.1.2.2.3 Suggested Formula for Cargo Flights For cargo flights, we choose the transported goods weight as the priority indicator unit. We introduce the following criteria:

Id Name Value Origin

CWV Cargo Weight In 10 tons Airline

PDG Goods nature Dangerous = 10 Perishable = 5

Other = 1 Airline

We set down:

CFT = PDG * N10% * CWV * N11% And the PAC becomes:

CFT (1 + CFV + LFV + FTV) PAC = ------------------------------

FLOV1 (1 + SFV + PFV + EFV)



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Where: FLOV1 = Constant * N9%

The FLOV1 factor allows adjusting the cargo flight priority with respect to the passengers flight priority.

Figure 9: Cargo Flight Prioritisation

The prioritisation system uses the priority indicator to order the flights in a list.

3.1.2.3 PAC Editor The prototype is a pedagogical tool which allows establishing a priority formula but also testing and refining the processes. Below are simple PAC Editor requirements:

• The system shall provide a flight list display. • The system shall provide a priority formula editor. • The formula editor shall allow the selection of a set of criteria in a predefined

list. • The formula editor shall allow the creation from scratch of a set of criteria. • The system shall apply the priority formula to a flight list. • The system shall sort the flight list according to the priority values.



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Figure 10 shows a possible graphical user interface for the formula editor.

Figure 10: Priority Formula Editor

3.1.2.4 Airport Auto-Regulation The airport auto-regulation is a process managing the flights during adverse conditions. The idea is to determine the number of flights that can depart according to an average agreed delay. The selection of flights for departure will then be done in relation to the flight priority. The current airport capacity fixes the maximum number of flights or movements for departure. The flights’ ordering allows selecting the maximum number of flights as candidates for departure and to draw out the flights rejected. The correct solution is to find a balance between the number of delayed flights and the average delay per flight acceptable for the partners on the airport. For instance, as a result of a disruption the average delay per flight is anticipated to be around 30 minutes before the take-off time. The airport partners suspend a number of selected flights until the average delay reaches around 15 minutes if 15 minutes is the acceptable delay for the partners on the airport. All the favoured flights are sure to start according to the average delay.



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The auto-regulation system has to allow partners adjusting their own choice during the disruption period taking into account the real time preferences or constraints:

• Airport: real airport capacity and the airlines demand, • Airlines: swapping between selected flights and not selected flights.

The auto-regulation system will avoid disrupting the current departure sequence at the TWR level, i.e., 15 minutes before TOBT.



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3.2 Concept Evaluation

3.2.1 FEW

3.2.1.1 KPI Definition The Key Performance Indicator evaluating the concept efficiency is the time gained by the favoured flights.

3.2.1.2 Simulations We suggest two types of simulations:

• a fast-time simulation to quantify the time gained when FEW is taken into account, and

• a real-time simulation to assess the impact on the controller working habits. The fast-time simulation will focus on the ground phase and measure the time gained during sequencing operations, taxiway controls and handling actions. The real-time simulation will focus on the en-route phase and evaluate how the FEW can be integrated in the controller orders: direct, conflict resolution, vectoring, re-routing and holding stack sequence. The scenario required for these simulations is a 1-hour traffic during peak hours with many flights from the same airline, allowing the swapping between flights.

3.2.2 PAC

3.2.2.1 KPI Definition The average delay is a Key Performance Indicator evaluating the auto-regulation efficiency. It can be measured in minutes per flight but also in minutes per passenger. The last indicator is interesting as it reflects the passenger satisfaction. It is worth also to measure the number of flights impacted by the auto-regulation process. The simulations will also allow measuring the impact of the airport auto-regulation on the ATFM regulation (CFMU) in terms of:

• total traffic delay, • number of flights with a CTOT (CFMU slot), • average delay of the ATFM regulation.



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3.2.2.2 Simulations A PAC simulation should include the following tasks:

• the auto-regulation process, • the average delay management and • the actions performed on the pending flights.

We suggest two different scenarios: one with a runway capacity reduced by 15% and one with a runway capacity reduced by 80%, these two scenarios proposing a 2-hour traffic.

3.2.2.3 Auto-Regulation Process In this section, we propose an implementation of the airport auto-regulation process. The two main parameters of this process are:

• MxD, the maximum number of flight departures (estimated airport capacity) and, • Nmx%, the percentage of additional flights planned for departure (these flights

act as a buffer). We define Cr-MxD = MxD (1+ Nmx %). Cr-MxD represents the number of flights the auto-regulation process will handle. The maximum number of flight departures (MxD) varies with the external conditions at airport. The percentage of additional flights (Nmx %) is determined by the average delay acceptable by the airport partners. Note that the higher the percentage factor Nmx %:

• the less effective the airport auto-regulation will be, • the more the CFMU regulations will take place, • the more important the average delay will be.



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Figure 11: Airport Crisis & Regulation

The auto-regulation process starts when:

• MxD < DEM and • Current delay per flight is greater than the average acceptable delay.

Figure 11 gives an example of factor (Nmx %). We can see that factor (Nmx %) variation fixes the acceptable delay and depends on the forecast of the traffic demand (DEM) and on the current capacity (MxD). The airport auto-regulation manages three flight lists containing departure flights for the next hour. Each list is split into four quarters of an hour. The flights are ordered by their priority factor. The three lists are:

• CR-FPL list, which contains all the flights, • CR-Departure list, which contains the flights selected for departure, and • CR-Pending list, which contains the exceeding departure flights.

The CR-FPL list is divided into 4 quarters. The estimated take off time determines in which quarter a flight will be placed. When MxD < DEM, the auto-regulation system selects a number of flights (CR-MxD) in the current quarter Qx and adds these flights to the CR-Departure list Qx. The flights exceeding are added to the CR-Pending list Qx. When a flight is added to the CR-Pending list, the system erases its EOBT. Each quarter of the lists has its own parameters: MxD, CR-MxD, average delay, Nmx %, DEM. The auto-regulation process is applied each time a parameter is modified.



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Figure 12 illustrates the lists management.

Figure 12: Auto-Regulation Processes

The auto-regulation operator can modify manually the last quarters three in each list. He can:

• Swap two flights between two lists (CR-Departure & CR-Pending lists), • Move a flight to a chosen position in a list, the system will maintain the ordering

value, • Modify the parameters Nmx %, adjusting the severity of the airport auto-

regulation. The first quarter of the lists cannot be modified. The flights are close of the departure and can be considered in departure sequence. An airline has several possible actions on flights from the CR-Pending list. They can:

• Suppress a flight from the CR-Pending list or the CR-Departure list, • Update a flight with a new EOBT in the CR-Pending list, and • Ask for a swap between two flights in lists CR-Departure & CR-Pending.



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Figure 13 shows how an airline can update a flight EOBT and how the system manages this update.

Figure 13: Airline Re-issues a Cancelled Flight

When an airline suppresses a flight in the CR-Departure list, the first flight in the CR-Pending list is moved to the CR-Departure list (previous EOBT is regenerated). When an airline regenerates an EOBT, the estimated take off time is re-evaluated by the TWR. The updated flight is removed from the CR-Pending list and is added to the corresponding quarter of the CR-Departure list. The whole process is then applied to this quarter. The swapping is a feature the airline can use for its crew or fleet management (change of crew if the delay increases, gathering two flights with a bigger aircraft, etc.). The airline need not provide the real reason. In case of swapping between a flight from the CR-Pending list and a flight from the CR-Departure list, the flights exchange their ordering values. The auto-regulation ends when:

• Current delay per flight is less than the acceptable delay and • CR-Pending list is empty.



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4 Conclusion This document presents the flight prioritisation concept. Flight prioritisation is considered from two points of view: network and private. This concept is motivated by increasing delays at airports and difficulties in recovering from adverse conditions. This document should be considered as a basis for flight prioritisation evaluation. It provides guidelines to implement a prototype, to set up operational processes and to assess benefits.



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Glossary of Terms and Abbreviations ADEP Departure Airport ADES Destination Airport ATC Air Traffic Control ATFM Air Traffic Flow Management ATM Air Traffic Management ATS Air Traffic System CFMU Central Flow Management Unit DPI Departure Planning Information EOBT Estimated Off-Block Time FEW Flight Economical Weight FMP Flow Management Position FPL Flight Plan FUM Flight Update Message KPI Key Performance Indicator OCC Operations Control Centre PAC Priority in Adverse Conditions SEE Society Environment Economy SLA Service Level Agreement TWR Tower

© European Organisation for the Safety of Air Navigation (EUROCONTROL) May 2006 This document is published by EUROCONTROL in the interest of the exchange of information. It may be copied in whole or in part, providing that the copyright notice and disclaimer are included. The information contained in this document may not be modified without prior written permission from EUROCONTROL. EUROCONTROL makes no warranty, either implied or express, for the information contained in this document, neither does it assume any legal liability or responsibility for the accuracy completeness or usefulness of this information. EUROCONTROL Experimental Centre Centre de Bois des Bordes BP15 91222 Brétigny sur Orge Cedex France Tel: +33 1 69 88 75 00 Fax: +33 1 69 88 75 05 (EUROCONTROL) May 2006

Documents

EEC SEE 2006 002 - Eurocontrol · One of the keys to success of flight prioritisation is to determine the best time to switch from private priority to network priority. If the required