ETFMS

ETFMS means Enhanced Tactical Flow Management System in French: System improved of tactical management of flows (air).

Description

Computing system created already 10 years ago by Eurocontrol (service of CFMU) to calculate the time slot of takeoff of each Avion taking off from the zone ECAC in order to minimize the number of overloaded air sector.

Written in ADA, and turning under HP-UX, the system is based on an exchange of messages between the airline companies (which will deposit/change/update flight plans), the organizations of air control and CFMU, the messages being written with the format ADEXP.

ETFMS uses at least 5 basic concepts:

Flight plan: described the trajectory 4D of a plane.
regulation: rate of planes applied to a “traffic volume”. Example: 50 planes/hour
“traffic volume”: association of a geographical reference frame (air sector, not of road, airport, etc) and of a whole of flow of planes.
list of time slots of takeoff or called slot . Example: if the rate of the regulation is 30 avions/h, there will exist a crenel every 2 minutes: 10 hours, 10 H2, etc
the time: difference in time between the schedule of takeoff wanted by the company and the schedule calculated by ETFMS.

In fact the regulators of CFMU will create regulations according to the state of the traffic of the day or the days to come (2 days in advance).

Operation

The usual process is held as follows:

sends of a message of deposit of flight plan to two units IFPS (IFPU1 in Brussels-Belgium and IFPU2 with Bretigny On Barley-France). The responsibility for the treatment of the FPL between the two units is determined by the aerodrome starting. Responsible unit IFPS checks the flight plan in a seéuence as follows:

1.Syntax - the format of the message must be in conformity with published in Appendix 2 of Document 4444 of the ICAO.

2.EFPM - Abbreviation of Extended Plane Flight Message, message FPL must be coherent with information already present in system IFPS.

3.Route - the road must be coherent with the publications nationals (AIPs).

4.Profile - the calculation of the profile in 4 dimensions must be valid (performance avion+RAD). This deposit must be carried out 3:00 before the takeoff of the plane under penalty of penalties (in the form of time on takeoff if the flight is sumit with regulation ATFCM).

Once validated, the flight plan is sent to ETFMS itself which will calculate its profile 4D in order to know in which sectors it will pass.
If the flight passes by one or more regulations:

If it passes by only one regulation, the algorithm will seek in the list of the crenels associated nearest with the request made by the company. For example, if the company wants that this plane takes off with 10:10 and that the crenel 10:10 is occupied by another plane, then it will take the next free one: 10:12 (with a rate of 30 planes per hour). This plane will then be declared " retardé" and its delay quantified at 2 minutes.
If the plane passes by several controlled sectors, one observes the same preceding rule and one chooses the crenel which gives the greatest time (in order to maximize safety).
It arrives that the flight does not pass by any regulation, and thus does not have a crenel of takeoff: the company can take off per hour that it indicated (subject to the crenels of takeoff airport!)

If a crenel is calculated, a message is sent to the company announcing the choice to him. The company has the choice to accept or refuse this crenel and to ask another with criteria of them. This phase of " négociation" is held imperatively 30 minutes before the hour of takeoff.
Once the accepted crenel, a message is sent to the control centers to update the associated flight plan.

There also exists of other types of messages between the airline companies and CFMU making it possible to inform of the state of the plane (ready to take off) or to suspend it (plane in of-icing during a snowstorm).

Currently, ETFMS includes new messages making it possible to set up a system CDM in Europe in the form of two messages: FUM and DPI.

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