Airport Collaborative Decision Making (A-CDM) in Spain

PT 4 M minute read
Airport Collaborative Decision Making (A-CDM) in Spain

This is a post by author Gonzalo Barona, Jr. Gonzalo is the Madrid station manager for Universal Aviation Spain, which has aircraft ground handling facilities in Madrid, Girona, and Barcelona. Gonzalo is an expert on business aircraft operations in Spain and can be contacted at

Airport Collaborative Decision Making (A-CDM) is a system developed by Eurocontrol and the European Union (EU) to improve operational efficiency at high-traffic airports. It does this by reducing delays, better utilizing infrastructure and resources, and optimizing traffic flow. Two airports in Spain have now implemented CDM systems, and there will be more added to the network in the future.

If you are operating your business aircraft to Spain, the following is an overview of what you need to know about A-CDM:

1. CDM objective

Operations in Spain require airway slots, with large international airports also requiring airport slots. These two slots need to be arranged through different entities. Schedule revisions require changes to both airway and airport slots, with Eurocontrol airway slots always taking priority. CDM programs determine if airway and airport slots match flight plans. CDM systems in Spain are primarily focused on departures, with one objective being a reduction in lines of aircraft – with engines running – waiting for departure. In the event of a missed match, flight plans are auto-cancelled. If operators are not careful, both airport and airway slots may be cancelled as a result of even small schedule changes.

2. CDM in Spain

Spain’s A-CDM system was developed by Aeropuertos Espanoles y Aeronavegacion Aerea (AENA). Currently, Madrid Barajas (LEMD) and Barcelona (LEBL) are the only active CDM locations. Palma de Mallorca (LEPA) was planned to be part of the CDM system in early 2015, but this has been postponed until 2016.

3. CDM process

The first step in the CDM process is to obtain a confirmed departure airport slot. This should be done as early as possible. For example, if your airport slot is confirmed for 1905 UTC, you’ll need to file a flight plan for this specific time. If the airport slot and the flight plan time do not match, the CDM system auto-cancels the flight plan. Once a flight plan is filed, Eurocontrol’s Central Flow Management Unit (CFMU) connects to the CDM system and indicates the airway slot given, in order to regulate time of takeoff.

4. CDM calculations

CDM calculates the time it takes from the parking stand to the taxiway and runway, and it gives you a departure time. Once you’re off-blocks, at the time the ground handler assigns, CDM provides you with a +5 minute clearance start time. You must ensure you are 100% ready to depart when you request clearance start time because, once you have a start time, you must adhere to it. If you do not use an assigned clearance start time, everything auto-cancels, and you’ll need to refile another airport slot and flight plan.

5. Ground handler responsibilities

Your handler needs to ensure that both the CDM system is updated and that you are advised of any airway slot delays. To calculate timing of these various steps, your handler must know when passengers will arrive and how long it will take crew members to arrange departure. As only your handler has access to the CDM website, crew members are not able to manage this process directly.

6. CDM implementation

AENA implements A-CDM at airports with heavy traffic movements in order to achieve maximum operational efficiency gains. In October 2014, A-CDM went live at LEMD followed by LEBL in February 2015. In 2016, CDM will be implemented at LEPA. We understand that Ibiza (LEIB) and Valencia (LEVC) are also likely to implement CDM systems in the future although no firm dates have been decided. At this point in time, there are no plans to inaugurate A-CDM at smaller airports in Spain without heavy traffic.

7. Impact on operations

With implementation of CDM, the affected Spanish airports have increased efficiency and have allowed operators ready to depart to leave earlier than aircraft not ready to receive their clearances. In many cases this new CDM system has made it possible for operators to leave several minutes earlier than expected.

8. Impact on ATM network

Any information inserted into the CDM system shows up on the European Air Traffic Management (ATM) network so that it can be checked and validity confirmed. For example if you have a 1900 UTC airport slot and try to update to 1915 UTC in the system, ATM will not allow you to make the change as it does not match up with your airport slot.

9. Ground handler requirements

Once ground handlers are licensed for CDM at particular airports and receive user names and access codes, they provide a list of operators they handle. If they need to add an operator to their lists, they must obtain permission for that particular flight. In order to have access to the CDM system, ground handlers must be licensed for specific airports – in this case either LEMD or LEBL. So, it’s important to ensure that your handler is appropriately licensed to access CDM at the airport where you’ll receive services. If you’re traveling to LEBL, but the ground handler is only licensed for LEMD, he or she will not be able to handle your aircraft at LEBL without access to LEBL’s CDM system.

10. Additional information

For more information on CDM and its impact on operations at Spanish airports, see: and


It’s important to ensure you’re ready for departure before updating the CDM system as, once the process starts, the clearance must be used. This new process has reduced delays at both LEMD and LEBL. In the future AENA will implement this at airports with high traffic, such as LEPA, LEIB, and LEVC, to further enhance operations at those airports.


If you have any questions about this article or would like assistance planning your next trip to Spain, contact me at

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