Adverse Conditions (Concept Element)

“Adverse Conditions Element consists of collaborative management of the capacity of an airport during periods of a predicted or unpredicted reduction of capacity.



The aim is to achieve a common situational awareness for the Airport CDM Partners, including better information for the passengers, in anticipation of a disruption and expeditious recovery after the disruption.



The Concept Elements Information Sharing, Milestones Approach, Variable Taxi Time, and Pre-departure Sequencing need to be implemented at the airport before Adverse Conditions can be implemented successfully.

Airport Collaborative Decision Making (Airport CDM)

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.

Implementation of Airport CDM allows each Airport CDM Partner to optimise their decisions in collaboration with other Airport CDM Partners, knowing their preferences and constraints and the actual and predicted situation.

The decision making by the Airport CDM Partners is facilitated by the sharing of accurate and timely information and by adapted procedures, mechanisms and tools.

The Airport CDM concept is divided in the following Elements:
·         Information Sharing
·         Milestone Approach
·         Variable Taxi Time
·         Pre-departure Sequencing
·         Adverse Conditions
·         Collaborative Management of Flight Updates

Note: Airport CDM is also the name of the EUROCONTROL project coordinating  the  implementation  of  the  Airport  CDM  concept  on  ECAC  airports.  This project is part of the DMEAN and SESAR programs.

Airport CDM Information Sharing (Concept Element)

The  Information  Sharing  Element  defines  the  sharing  of  accurate  and  timely information  between  the  Airport  CDM  Partners  in  order  to  achieve  common situational awareness and to improve traffic event predictability.The Airport CDM Information Sharing Platform (ACISP), together with defined procedures agreed by the partners, is the means used to reach these aims.

Information  Sharing  is  the  core  Airport  CDM  Element  and  the  foundation  for the other Airport CDM Elements. It needs to be implemented before any other Concept Element.

Airport CDM Information Sharing Platform (ACISP)

The Airport CDM Information Sharing Platform (ACISP) is a generic term used to describe the means at a CDM Airport of providing Information Sharing between the Airport CDM Partners. The ACISP can comprise of systems, databases, and user interfaces.

Airport CDM Partner

An Airport CDM Partner is a stakeholder of a CDM Airport, who participates in the CDM process. The main Airport CDM Partners are:
·         Airport Operator
·         Aircraft Operators
·         Ground Handlers
·         De-icing companies
·         Air Navigation Service Provider (ATC)
·         NMOC
·         Support services (Police, Customs and Immigration etc)


A system generated message which alerts the Airport CDM Partners of an irregularity and which normally requires one or more partners to make a manual intervention to resolve the irregularity.

CDM Airport

An  airport  is  considered  a  CDM  Airport  when  Information  Sharing,  Milestone Approach, Variable Taxi Time, Pre-departure Sequencing, Adverse Conditions and  Collaborative  Management  of  Flight  Updates  Elements  are  successfully implemented at the airport.

Collaborative Manage- ment of Flight Updates (Concept Element)

The Collaborative Management of Flight Updates Element consists of exchanging  Flight  Update  Messages  (FUM)  and  Departure  Planning  Information  (DPI) messages between the NMOC and a CDM Airport, to provide estimates for arriving flights to CDM Airports and improve the ATFM slot management process for departing flights.

The aim is to improve the coordination between Air Traffic Flow and Capacity Management (ATFCM) and airport operations at a CDM Airport.

The Concept Elements Information Sharing, Milestone Approach, Variable Taxi Time, Pre-departure Sequencing, and Adverse Conditions need to be implemented at the airport before the Collaborative Management of Flight Updates can be implemented in cooperation with NMOC.

Pre-departure Sequencing (Concept Element)

The  pre-departure  sequence  is  the  order  that  aircraft  are  planned  to  depart from their stands (push off-blocks) taking into account partners' preferences.  It should not be confused with the pre-take off order where ATC organise aircrafts at the holding point of a runway.

The aim is to enhance flexibility, increase punctuality and improve slot-adherence while allowing the airport partners to express their preferences.

The Concept Elements Information Sharing, Milestone Approach, and Variable Taxi Time need to be implemented at the airport before the Pre-departure Sequencing can be implemented.

Note: The pre-departure sequence can also be derived by a departure manager(DMAN), which calculates based on demand the take off time TTOT and derives the TSAT from the runway sequence. Airports can implement different solutions to achieve the pre-departure sequence, depending on local traffic complexity and surface congestion.

Milestone Approach (Concept Element)

The  Milestone  Approach  Element  describes  the  progress  of  a  flight  from  the initial planning to the take off by defining Milestones to enable close monitoring of significant events.

The aim is to achieve a common situational awareness and to predict the forth coming events for each flight with off-blocks and take off as the most critical events.

he  Concept  Element  Information  Sharing  needs  to  be  implemented  at  the airport before it can successfully implement the Milestone Approach.

The Milestone Approach combined with the Information Sharing element is the foundation for all other Concept Elements.


An event is a distinct occurrence in the planning or operations of a flight that a person or system perceives and responds to in a specific way.

Ground Handling

Ground Handling covers a complex series of processes and services that are required to separate an aircraft from its load (passengers, baggage, cargo and mail) on arrival and combine it with its load prior to departure. [Source:]

Ground Handler

A Ground Handler is the company or person(s) that perform ground handling.


This  is  a  significant  event  that  occurs  during  the  planning  or  operation  of  a flight.

A successfully completed milestone will trigger the decision making process for downstream events and influence both the further progress of the flight and the accuracy with which the progress can be predicted.

Variable Taxi Time

Variable Taxi Time is the estimated time that an aircraft spends taxiing between its parking stand and the runway or vice versa.
Variable Taxi Time is the generic name for both inbound as outbound taxi time parameters, used for calculation of TTOT or TSAT. Inbound taxi time (EXIT) includes runway occupancy and ground movement time, whereas outbound taxi time (EXOT) includes push back & start up time, ground movement, remote or apron de-icing, and runway holding times.

Variable Taxi Time (Concept Element)

The Variable Taxi Time Element consists of calculating and distributing to the Airport  CDM  Partners  accurate  estimates  of  taxi-in  and  taxi-out  times  to  improve the estimates of in-block and take off times. The complexity of the calculation may vary according to the needs and constraints at the CDM Airport.
The aim is to improve the traffic predictability.

The Concept Elements Information Sharing and Milestone Approach need to be implemented at the airport before Variable Taxi Time can be implemented.