55TH ANNUAL CONFERENCE, Las Vegas, USA, 14-18 March 2016
WP No. 157
Airport CDM (A-CDM)
Presented by TOC
Although the main objective of A-CDM is always the same; information sharing in order to optimize traffic flows and reduce delays, the execution differs per country. ICAO is working on an A-CDM manual with information on the purpose of A-CDM, methods and tools and best practices for implementing. This information paper gives a short summary of the information in the ICAO manual, which will be published in 2016.
1.1 Collaborative Decision Making (CDM) is a famous concept, also used in several segments within aviation.
1.2 ICAO is working on an Airport CDM (A-CDM) Manual, which is expected to be published in 2016. The manual gives a description of ACDM, identifies the different actors and stakeholders, discusses several methods and tools and provides some best practices on the implementation of A-CDM.
1.3 In June 2012 the Airport Governing Body ACI and the Civil Air Navigation Services Organisation (CANSO) – on behalf of the world’s ANSPs and ATM Network- signed a Memorandum of Cooperation (MOC) to co-operate and co-ordinate their respective initiatives aiming to implement A-CDM worldwide, recognising the potential benefits of expanding the European A-CDM concept.
Together the organisations are working on an A-CDM Guidance Document and are developing a pool of A-CDM Subject Matter Experts. Furthermore CANSO was cooperating on the ICAO Manual.
1.4 This paper gives a short review of the A-CDM concept and the implementation challenges, summarizing the information, which will be available in the ICAO manual.
2.1 The process of A-CDM has developed from the overall philosophy of CDM in aviation. The concept enables the sharing of information between stakeholders and predefines the rules and procedures for collaboration.
|A-CDM is a process that allows airport operators, aircraft operators, air traffic controllers, ground handling agents, pilots and air traffic flow managers to exchange operational information and work together to efficiently manage operations at airports and, where applicable, en route operations and planning.|
(ICAO Annex 14)
A-CDM helps optimizing the use of all airport resources, reduce arrival and departure delays, and improve predictability during regular and irregular operations. The main objective of A-CDM is to generate a common situational awareness that will foster improved decision-making (1.1 Description & purpose of Airport CDM – ICAO A-CDM Manual, Draft version).
2.2 As already touched in the definition, information sharing and transparency are key enablers for A-CDM. All stakeholders will still make their own decisions, but the flight information will be shared in order to create a common situational awareness. This could be done in varies ways, e.g. an A-CDM dialog system or an A-CDM Information Sharing Platform, depending on the technical possibilities of the airport and its stakeholders.
2.2.1 The number of participants involved varies from aerodrome to aerodrome, but the process should always involve at least three different partners: the aerodrome operator, aircraft operators and the Air Navigation Service Provider (ANSP). Other entities such as an ATFM network manager, meteorological service or airport terminal operators for example may also play an important role.
Every A-CDM process is different, and it should always be adjusted to the local needs, requirements and constraints of the airport.
2.3 The ASBUs (Aviation System Block Upgrades) – designed to leverage existing technologies and anticipating future developments based on State/industry agreed operational objectives – address A-CDM and compose two blocks; B0-ACDM and B1- ACDM. These blocks help States implement A-CDM in a harmonized and consistent manner and identify the target availability timelines for operational improvement.
2.3.1 The B0-ACDM block is entitled “Improved Operations trough Airport-CDM” and is defined as follows:
|Implements collaborative applications that will allow the sharing of surface operations data among the different stakeholders on the airport. This will improve surface traffic management reducing delays on movement and maneuvering areas and enhance safety, efficiency, and situational awareness.|
(ICAO A-CDM Manual)
22.214.171.124 The B0-ACDM block is also linked to the B0-RSEQ and B0-SURF modules.
126.96.36.199 B0-RSEQ improves a traffic flow trough runway sequencing by introducing system capabilities such as an Arrival Manager (AMAN) or Departure Manager (DMAN) to provide assistance for sequencing and metering. By using well planned start up and push back clearances for instance, taxi times and ground holding are reduced and surface congestion is reduced, creating a more efficient departure sequence.
188.8.131.52 B0-SURF focuses on the Safety and Efficiency of Surface Operations and Enhanced Vision Systems and is about the implementation of additional capabilities to the airport surveillance environment in order to specifically identify targets with individual flight/vehicle identification.
2.3.2 Block 1-ACDM is entitled “Optimized Airport Operations through A-CDM Total Airport Management” and is defined as follows:
|Enhances the planning and management of Airport Operations and allows their full integration for air traffic management using performance targets compliant with those of the surrounding airspace. This entails implementing collaborative airport operations planning (AOP) and where needed, an airport operations center (APOC).|
(ICAO A-CDM Manual)
2.4 While the first object of A-CDM is to improve local operations at airports, much benefit can be obtained when linking these operations to the ATM network. Although ATFM (Air Traffic Flow Management) is not a pre-requisite for A-CDM, it is evident that any form of ATFM will benefit from being connected to A-CDM (ICAO A-CDM Manual – 1.4 Link with ATFM). Up to date arrival information from the ATM network will contribute to the A-CDM operations, while the ATFM Network Operations will benefit from more accurate departure information from A-CDM airports.
2.5 Since the start of the implementation of A-CDM in 2007 benefits for several stakeholders have been measured and proven. For Air Traffic Control operational and financial benefits can be found in decreased taxi time, decreased controller workload, improved stability of operations under adverse situations and increased airport throughput.
2.6 Although several States all have their own A-CDM implementations, these can all be traced back to two different main A-CDM structures; the European and the US version.
2.6.1 In Europe A-CDM is seen as a part of optimizing the overall ATFM process. The Eurocontrol A-CDM Manual defines the concept as follows:
|Airport Collaborative Decision Making is the concept which aims at improving Air Traffic Flow and Capacity Management (ATFCM) at airports by reducing delays, improving the predictability of events and optimising the utilisation of resources.|
184.108.40.206 The European process is very much focussed on the turnaround process of flights at airports. Planning and information of arriving flights is linked with the following departing flight to ensure the feasibility of the turnaround process. The European A-CDM Process is composed of the following elements:
- Information Sharing to ensure common situational awareness
- Milestone Approach to track the progress of the flight event
- Variable Taxi Time for more accurate in-block and take off time predictability
- Pre-departure Sequencing to plan when aircraft leave their stands (push off-blocks)
- Adverse Conditions to complete A-CDM process for all kind of operations
- Collaborative Management of Flight Updates to connect the local Airport CDM to the ATM network (ICAO A-CDM Manual – 1.8.1 European Airport CDM)
2.6.2 The US Surface CDM is an important part of the overall US CDM process. Similar to Europe the CDM process is all about creating a common situational awareness, however the US Surface CDM focuses very much on the management of airport surface traffic flows and runway departure queues.
The US CDM process is defined as follows:
|Collaborative Decision Making (CDM) is a joint government/industry initiative aimed at improving air traffic flow management through increased information exchange among aviation community stakeholders|
2.7 An A-CDM process is a process on the day of operation of the flight. It should be seen as a timeline comprising different possible milestones. Such a milestone is either an operational event or a certain point in time.
2.7.1 Several planning times are used in the process, which already starts prior to departure. The flight information is updated and shared at every milestone. When the flight is inbound, planning information is being processed to determine the Estimated In Block Time (EIBT). Both the flight crew and air traffic control are aware of planning times such as Target Off Block Time (TOBT), Target Start up Approval Time (TSAT) and Target Take Of Time (TTOT). Every so-called target time has a window of a certain amount of minutes, which the flight can deviate from that time. Once one of the Target Times is not met, a new optimal planning is being calculated. Where A-CDM had been implemented, the “first come – first served” principle is not applicable anymore.
2.8 The A-CDM process depends on the quality of the delivered information input by every single one of the partners. Information needs to be reliable to achieve a reliable and useful result for both single flights and overall operations. The roles and responsibilities of all partners need to be formalised in a Memorandum of Understanding, Service Level Agreement or specific contracts.
2.9 Implementing A-CDM, in any of the abovementioned forms, is not an easy task.
2.9.1 Before beginning to plan implementation of A-CDM a thorough cost-benefit and gap analysis must be performed to ascertain whether the significant financial and personnel investment is proportionate to the expected local benefits.
2.9.2 All stakeholders in A-CDM at the affected airport must be on board and committed to implementation. A-CDM requires a number of significant changes in the way parties at the airport operate. Problems will arise, some predictable, some not so much. When they do, it is imperative that all stakeholders work together to overcome the difficulties they present. This is important in order to foster willingness to see the project through. If one of the stakeholders is perceived to not be fully committed it will become much more difficult to successfully complete the project and the benefits will remain out of reach.
2.9.3 Different stakeholders prioritise different aspects of the information sharing process, as their workloads and benefits are particular to their specialties. This makes it very important that there is constructive and continuous coordination between the affected parties as compromise is almost always necessary. Especially at high density traffic aerodromes the financial outlay can be high for the stakeholders while benefits are relatively low at a local level.
2.9.4 Just before and after implementation, workload can increase significantly for those in operational ATC positions, the flight deck, airline operational centres and ground handling. Unfamiliarity with the new procedures on both crew and ATCO side can lead to confusion on the frequency and frustration when the system appears to block operations that were previously based on the simple (but less efficient in the long run) “first-come-first-served”-principle. At this stage proper training and constant evaluation are necessary in order to iron out any issues that accompany implementation. This is also vital as part of an effort to keep operational personnel on board with the concept.
2.10 Eurocontrol has conducted a study looking at the network benefits of A-CDM according to the European concept (“A-CDM Benefits Study – Update” – Denis Huet, Eurocontrol in November 2015).
2.10.1 In the study, the 16 European CDM airports were studied to determine the effects of A- CDM on local operations and on the network in general. The study showed a marked improvement in departure capacity, recovery time after adverse conditions and overall network capacity. A significant benefit was also identified in more accurate take-off time prediction, which in turn led to a reduction in sector over-delivery. On the whole this increased European network predictability and produced significant benefits to network capacity.
2.10.2 It is estimated that the increase in capacity of the European network will reach between 3% and 5.5% due to A-CDM. It is forecast that as more airports implement A-CDM the benefits to the overall network are incrementally less, but of course the local benefits will still apply.
2.10.3 The full study on the benefits of A-CDM in Europe as per the implementation at 16 airports is due to be published in January 2016. It is not available as per the deadline of this paper, but will be by the time of the IFATCA conference in Las Vegas.
3.1 A-CDM is a process that allows airport operators, aircraft operators, air traffic controllers, ground handling agents, pilots and air traffic flow managers to exchange operational information and work together to efficiently manage operations at airports and, where applicable, en route operations and planning.
3.2 Although every A-CDM process is different, and should always be adjusted to the local needs, requirements and constraints of the airport, information sharing and transparency are key enablers in every situation.
3.3 Decreased taxi time, decreased controller workload, improved stability of operations under adverse situations and increased airport throughputs are a few examples of the operational and financial benefits for ATC.
3.4 While the European A-CDM process is very much focussed on the turnaround process of flights at airports, the US Surface CDM focuses very much on the management of airport surface traffic flows and runway departure queues.
3.5 The A-CDM process depends on the quality of the delivered information input by every single one of the partners. Information needs to be reliable to achieve a reliable and useful result for both single flights and overall operations.
3.6 A-CDM requires a number of significant changes in the way parties at the airport operate. It is imperative that all stakeholders work together to overcome the possible difficulties that implementation of the concept causes.
It is recommended that;
That this is accepted as information material.
Doc 9971, Manual on CDM – ICAO
A-CDM Manual – ICAO
Airport CDM Guide – Eurocontrol, July 2003
Airport CDM Implementation, The Manual – Eurocontrol, 2012
ACNZ New Zealand A-CDM ConOps –
CDM Factsheet – Air Services Australia
Collaborative Decision Making for the Optimisation of Network Management – An Operational Concept V1.0 – Air Services Australia
Last Update: October 1, 2020