What is Airport Collaborative Decision-Making (A-CDM)?

Aviation consultancies always aim to improve the efficiency of airport operations by optimising resources and improving the predictability of air traffic. Innovative technological tools such as A-CDM, which is being implemented with great success by an increasing number of airports in Europe and the rest of the world, are available to achieve these objectives.

What is CDM in airports?

A-CDM stands for “Airport Collaborative Decision-Making”. Many stakeholders work in an airport to guarantee dynamic operation of all infrastructures, and collaborative decision-making is essential for all of them.

A-CDM is a joint project between ACI Europe, EUROCONTROL, IATA (International Air Transport Association) and CANSO (Civil Air Navigation Services Organisation). Airport CDM aims to help improve operational efficiency at airports with the following objectives:

  • Optimise the use of all available resources (material and human).
  • Increase the predictability of all operations.
  • Schedule take-offs with greater precision.
  • Minimise delays.
  • Reduce environmental impact.

Real-time information exchange between airport operators, aircraft, air traffic control (ATC) and ground handling services must be enhanced to achieve these goals. This seamless data exchange requires the implementation of a series of operational procedures and automated processes.

The first airport to implement A-CDM was Brussels, followed by Munich, and subsequently the vast majority of European airports have been added, with 33 airports now in operation. These are:

  • Amsterdam (AMS).
  • Barcelona (BCN).
  • Bergamo (BGY).
  • Berlin Brandenburg (BER).
  • Brussels (BRU).
  • Copenhagen (CPH).
  • Düsseldorf (DUS).
  • Frankfurt (FRA).
  • Geneva (GVA).
  • Hamburg (HAM).
  • Helsinki (HEL).
  • Lisbon (LIS).
  • London Heathrow (LHR).
  • Lyon (LYS).
  • Madrid (MAD).
  • Malaga (AGP).
  • Milan Linate (LIN).
  • Milan Malpensa (MXP).
  • Munich (MUC).
  • Naples (NAP).
  • Nice (NCE).
  • Oslo Gardermoen (OSL).
  • Palma de Mallorca (PMI).
  • Paris Charles De Gaulle (CDG).
  • Paris Orly (ORY).
  • Prague (PRG).
  • Riga (RIX).
  • Rome Fiumicino (FCO).
  • Stuttgart (STR).
  • Venice (VCE).
  • Vienna (VIE)
  • Warsaw (WAW).
  • Zurich (ZRH).

Other airports such as Dublin, Manchester, London Gatwick, London Stansted, Stockholm or Istanbul are in the process of implementing A-CDM.

Defining collaborative decision-making

At airports where the concept is already implemented, A-CDM allows all those involved in the optimal operation of air traffic to work collaboratively and in a more transparent way, by sharing relevant and accurate information about their activities.

A-CDM represents a major change in the way airports operate, how they manage their resources and the way the agents involved in airport operations work. 

They are all committed to joint decision-making by sharing the up-to-date, available information. This results in better flight operations and more benefits for workers and passengers.

Both airlines and handling agents will have information available to plan their work in advance and improve the service. This reduces the cost of ground movements, with consequent financial savings and environmental impact.

Passengers have additional information about their flights and therefore benefit from better punctuality, reduced missed connections and better service during periods of disruption.

A-CDM Milestones

The A-CDM consists of 16 milestones that are grouped into three phases of an aircraft’s flight. The first phase is the approach to the airport, which refers to milestones 1-6. This is followed by the aircraft rotation phase at the airport, which includes milestones 7-15, and lastly, take-off, which is milestone number 16. 

The milestones are determined by times that are received from the different stakeholders involved and help to achieve greater precision in the operation. Therefore, the information managed in the environment of an operation must be reliable and in real time. 

A-CDM implementation

There are 5 phases involved in the implementation of the A-CDM, as it is a working methodology that requires a learning process. The first phase is based on analysing which milestone data can be collected for use in the A-CDM. The second stage is working on variable taxi times, which is more of a problem at large airports as the times are higher. The greater accuracy of the data will help the airport to be able to have estimated times closer to reality. 

The third stage of the implementation consists of pre-sequencing of departures, which assigns TOBT times considering the location of the airport and the preferences of the aircraft operator. These functions are provided by the air traffic control service provider, which manages take-off and landing operations at the airport. 

The fourth step is to adapt the system to an unfavourable airport environment such as bad weather, or other situations that cannot be foreseen and result in reduced airport capacity. Finally, we have the sixth stage, which focuses on the exchange of information between the airports with the A-CDM system and the air traffic control service providers in the network. 

Advanced ATC Tower

Smaller airports usually do not have a full A-CDM implementation. Integration with the ATFCM network is possible with the Advanced ATC Tower, which allows a part of the A-CDM information to be shared with the network. This option is also available for airports wishing to go one step further towards full A-CDM.

The Eurocontrol Network Manager also builds on the A-CDM concept and implements new and complementary concepts to support an even deeper integration of airports with the network. To do so, collaboration between all partners involved needs to be improved and optimised.


Airports that have successfully implemented A-CDM reflect any delays in the TOBT (Target Off-Block Time), which is the time at which the aircraft operator or ground manager estimates that an aircraft is ready to begin the stand-back manoeuvre, i.e. all gates are closed, the boarding bridge is removed, the pusher vehicle is present, the crew is ready and the clearance from the control tower.

The A-CDM automatically resolves the differences between TOBT and EOBT (Estimated Off Block Time), as both must be aligned to avoid last-minute flight delays.

Airport Gurus specialises in the implementation of new technological tools that improve the efficiency of airport operators, such as A-CDM. Contact us to answer any questions or queries you may have.

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