Safety nets are warning systems that aim to prevent imminent or hazardous situations from developing into major incidents or even accidents. They alert pilots and air traffic controllers to help avoid collisions between aircraft, as well as with terrain and obstacles. EUROCONTROL has played an integral role in supporting the safe implementation of safety nets across the European Civil Aviation Conference (ECAC) region over the past two decades. Early work focussed on raising awareness as well as developing agreed standards and guidance material. This led EUROCONTROL to commission us to undertake an ECAC-wide survey of ground-based safety nets for Air Traffic Control (ATC) in 2010, to assess the deployment of STCA, MSAW, APW and APM.

Nine years later, with many systems developments implemented and countless lessons learnt shared amongst stakeholders, it was time once again to assess the progress made.

Role of Egis

In 2010, we were commissioned to perform the first ECAC-wide survey of ground-based safety nets, addressing implementation levels, safety net performance, support requirements and more. This work involved detailed phone interviews with representatives from 33 Air Navigation Service Providers (ANSPs), followed-up by an online survey. Qualitative and quantitative analysis highlighted trends in the data gathered.

The research process had some additional benefits. It was useful to start building relationships with ANSPs that had not yet been involved in safety nets activities at the time. The exercise also assessed EUROCONTROL’s reach and customer satisfaction, and provided an opportunity to obtain suggestions for improvements.

Ten years on from the first survey, EUROCONTROL wished to update parts of that research to identify progress and outstanding gaps in implementation. Our team constructed a shorter online survey and communication plan, securing the participation of 35 ANSPs.

Our extensive knowledge of Air Traffic Management (ATM) systems and ATC terminology was key to the successful completion of both surveys. This proved essential to identifying subtleties in the way each safety net was implemented and operated, giving the survey results additional depth. Once the analysis was complete, we developed concise and informative slide decks for presentation to the Safety Team and more widely.


The 2010 survey identified gaps in implementation, highlighted the effectiveness of the guidance material, and recognised the benefits of the awareness raising activities undertaken by EUROCONTROL. It also enabled the identification of implementation issues, which helped the Safety Team focus efforts on the most pressing challenges. Different factors were studied, such as common issues across ANSPs but also other groupings (eg. system manufacturers). This supported European ANSPs in using their ground-based safety nets to their maximum potential.

In the follow up survey in 2019, the results showed an uptake in use of each ground-based safety net (see figure 1), with most also being extended to different operating environments or in more locations. An example of this is STCA which, by 2019, was more commonly deployed in both en-route and TMA, rather than just in en-route (see figure 2).

The increase in use and scope of ground-based safety nets across the ECAC region reflects the sustained efforts of EUROCONTROL, ATM system suppliers and the ANSP community. We are proud to have contributed to these achievements.

Figure 1: Number of ANSPs operating ground-based safety nets in ECAC Member States in 2010 and 2019
Figure 2: Number of ANSPs operating STCA in 2010 and 2019

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Ben Bouzon

Ben Bouzon

Principal Consultant

+44 1252 451 651