SSR code shortages are becoming a limiting factor to future growth in European air traffic levels and in traffic to new destinations within Europe. There are only 4096 Mode 3/A combinations to support identification and track-flight plan correlation of the flights.

Current SSR code management

The SSR codes are currently managed under the ICAO Originating Region Code Assignment Method (ORCAM) system. The ORCAM system is based on strategic allocations of sets of codes to individual States and the alternate use of transit and local definition of codes per Participating Areas (PAs): codes use for transit in one PA are used for local purposes in adjacent PAs. All together they cover the entire ICAO EUR Region.

The need for change

Since the mid 1990s, individual States have been forecasting potential shortages in their allotments of SSR codes to meet the forecast growth in air traffic.

Until now, changes to the ORCAM rules, Flight Data Processing System (FDPS) functionality upgrades, and close coordination between States, have ensured no major safety or capacity issues would arise on a routine basis.

Increasingly since 2000, ORCAM States have been raising serious concerns about the ability to meet future demand using the existing SSR code management methodology, for the following reasons:

The basis of ORCAM are the traffic flows and Participating Areas (PA) structure, designed over 20 years ago.

• The geo-political map of Europe changed.
• New States needed to be allotted with SSR codes.
• The use of secondary radar in neighbouring ICAO regions, such as Africa and Mid-Asia, is leading to more limitations in code usage.
• The levels of air traffic have risen considerably over the last decade and forecasts indicate that the level of traffic will continue to increase significantly.
• The instances of SSR code conflicts are increasing and are suffered by many of the ORCAM States.

The Agency set up a project for the development and the implementation of CCAMS, the Centralised SSR Code Assignment and Management System (CCAMS). It is a pan-European solution to overcome the current and future shortages of the SSR codes used by Air Traffic Control for radar services. Currently, implementation is planned in 16 States.

CCAMS User Group (CUG)Members

CCAMS User Group (CUG) Members nominated by ANSPs coordinate at local level the activities ensuring timely adaptations of local systems and are responsible for the development of procedures for the implementation of CCAMS.

CCAMS Project Team

The development and the implementation of CCAMS entails cross-domain expertise in operational management of SSR codes, design and functionalities of ATS systems and in the design and functionalities required for the central server of CCAMS. CCAMS Project Team gathers the required expertise from:

• DNM/COO/DCO/SCC (Surveillance and Code Coordination)
• CSPDU
• the Network Management Unit

For CUG Members and other project partners there is a secured website available on the EUROCONTROL OneSky Online.

Working arrangements

The Provisional Council of EUROCONTROL approved CCAMS at its 26th Session in November 2006. ICAO Paris has recognised CCAMS as the short- to medium-term solution to code shortages, as have Military Aviation, Industry and Airspace User Organisations at their respective high-level working arrangements.

CCAMS and other surveillance technologies

Selective interrogation technologies, such as Mode S, and other modern technologies, such as ADS, providing alternatives for the correlation of the radar tracks with the system flight plans are being implemented in parts of the European Region, and as such they represent the future in using surveillance for the provision of air traffic services.

However, in light of the deployment plans for these technologies it is foreseen that the need for Mode 3/A codes to provide unambiguous correlation and maintenance of the radar identification will last until at least 2025.

CCAMS will pave the way for deployment of ELS and other surveillance technologies, smoothing the transition process and providing for seamless introduction into operations.

A pan-European solution

Local deployments of the modern surveillance technologies provide alleviation for code shortages, but until they are deployed across Europe at a larger scale, these technologies will not be effective in mitigating the need for additional SSR Mode 3/A codes.

As indicated by States implementing ELS, the release of codes allocated through ORCAM is not foreseen for the upcoming years.

Consequently, a pan-European solution for providing sufficient SSR mode 3/A codes to address the traffic demand is essential.

Studies and modeling performed on optimistic traffic level forecasts indicating that a different management of the scarce resource of the existing SSR codes has the potential of easily accommodating the forecast traffic levels for 2012 and beyond.

This is the reason why experts recommended the implementation of a centralized management of the SSR codes, with the intention to close the gap until such time the deployment of Mode S and other surveillance technologies will provide the necessary identification and correlation functionalities on pan-European basis.

The benefits

CCAMS is a collaborative system for the most efficient use of Mode 3/A codes within the European network. It will provide:

• Efficient management of SSR codes
• Maximum retention of a code
• Reduction of code conflicts
• Flexibility to match future demands
• SSR codes for special events and military exercises

How will CCAMS operate?

CCAMS will consist of a central server located at the Network Management Unit. It will provide a unique code for each general air traffic operating within the region and it will :

• Automatically select and send a code to all the units along the route of the flight, based on the information available from other NM systems;
• Respond to code requests received from ATC units;
• Ensure a code conflict free trajectory of the flight, allowing the retention of this code within the CCAMS area;
• Monitor code use to ensure safe and efficient operations.