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.