Eurocontrol Continues Progress toward Mode S for Operational Use

Eurocontrol used a Mode-S downlink for the first time in January to identify and maintain surveillance of a flight without the assignment of a discrete secondary surveillance radar code.

A Lufthansa B-737 flying between Frankfurt and Munich became the first aircraft to have its flight identity that was transmitted by its Mode-S transponder, automatically correlated with its ATC flight plan.

Europe transitioned to the use of SSR for widespread ATC purposes during the 1960s and 70s. However, since SSR only provides 4096 codes, it can't support Europe's traffic growth; already there are more aircraft in the air over Europe at any one time than the available codes that can be assigned for the complete duration of each flight.

Eurocontrol says the success of this first flight paves the way for Germany's ANSP (air navigation service provider), Deutshe Flugsicherung (DFS), to continue inaugurating Mode S for this purpose throughout 2008.

Eurocontrol says neighboring ANSPs also will begin the transition to Mode S shortly.

Europe Starts Allocating Mode S Identifier Codes

In a related development, Eurocontrol has started allocating Mode-S ICs (interrogator codes) in order to selectively interrogate different aircraft.

Each SSR Mode-S sensor or cluster of sensors requires either an II (interrogator identifier) or SI (surveillance identifier), which are assigned by Eurocontrol's Mode-S IC Allocation Cell to ensure that identical codes aren't used in overlapping Mode-S coverage areas.

There are now more than 120 Mode-S radars operating, since they first began to be installed in 2002, but there are only 15 unique II codes. Demand for them now exceeds supply, which has resulted in coverage restrictions.

To deal with this situation, Eurocontrol has started allocating 63 new SI codes, the first of which have been assigned to radar installations in France and the Netherlands.

This expansion was made possible by Eurocontrol's mandate to carry SI-capable transponders, and will be further supported by a Single European Sky regulation developed in collaboration with the European Commission.  02-24-2008.

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