Laying the technical foundations to a future Single European Digital Sky

One of the most complex but important challenges facing European air navigation service providers (ANSPs) today is the challenge of modernising their legacy communications, navigation and surveillance (CNS) air traffic management (ATM) systems with new, digital architectures.

The ATM Master Plan promotes a vision of a “Digital European Sky”, which “will make Europe the most efficient and environmentally friendly sky to fly in the world by delivering a fully scalable system for crewed and uncrewed aviation, supported by a digital ecosystem, full air-ground system integration, distributed data services and high levels of automation and connectivity. Deployment should be completed by 2045.”

In December 2024 the SESAR JU launched the latest version of the European ATM Master Plan which sets out a high level view of the direction for investments and regulatory decisions needed to develop the Digital European Sky. The plan outlined 10 investment priorities for the next decade, supporting the twin transitions of digitalisation and sustainability. A major change is the adoption of a data-driven, cloud-based service-delivery model, enabling faster deployment of new features and better interoperability.

In parallel, EUROCONTROL launched its European CNS Evolution Plan, to give ANSPs more granular guidance on the evolutionary steps towards digitalisation needed to meet the ATM Master Plan objectives, in particular those linked to strategic objectives 7 and 9 related to CNS. “The European CNS Evolution Plan is set to become the strategic reference for the modernisation and optimisation of the European CNS infrastructure. It translates the European ATM Master Plan’s vision into an actionable roadmap,” said Predrag Vranjkovic, CNS Programme Manager Team Lead at EUROCONTROL.

This is the first version of the CNS Evolution Plan – a second, even more detailed plan with roadmaps and timescales, will be produced in 2026.

“We decided to take a two-stage approach because we quickly realised we could not do the detailed work in a single year,” said Predrag Vranjkovic. “We had to develop an evolutionary roadmap that everybody would support and there are many different interests to consider. So, in this first stage we have set out the main objectives and challenges, how we are going to work and the methodology on delivering the detailed implementation roadmaps.”

EUROCONTROL’s CNS Programme Manager (CNS PM) team is now working with almost 100 stakeholders on the detailed roadmaps for implementation. It is a complex task. Each stakeholder has its own approach to CNS/ATM technology procurement, with high levels of customisation and working to very different timescales for renewal. EUROCONTROL has a crucial role to play in the process, as an independent inter-governmental organisation with close links to the regulator and airspace users such as the military and general aviation who will need to be brought into the coordination process alongside ANSPs and technology providers.

“We know that the renewal cycles for major ATM systems are around 15 to 20 years, so we cannot suddenly say ‘switch everything off’,” said Predrag Vranjkovic. “Part of our work is to optimise what we already have and evolve in some kind of synchronised way. We will have to follow the renewal cycles.”

The document identifies legacy systems, such as Non-Directional Beacon (NDBs), which are obsolete, inefficient and should be switched off rather than replaced; other systems which will need individual assessments for renewal or replacement – such as satellite-based or ground-based landing aids – and other legacy systems such as Distance Measuring Equipment (DMEs), which should be enhanced.

The next stage in the CNS Evolution Plan is agreeing a roadmap for implementation, defining the implementation objectives in more detail and then, crucially, talking to the regulator on whether the implementation process should be carried out with incentives and/or mandates to implement critical technologies.

“Part of our task is to look at how we should move to this new technology through the EU regulatory system,” said Predrag Vranjkovic. “Our work package three is looking at cost-benefit-analysis issues, what kind of incentives we could propose to the Commission. Last year, I asked our ANSP stakeholders what kind of incentive would encourage them to optimise their CNS infrastructure, and they said, of course, if they could use potential savings of this optimisation to improve their “capacity.” So we have started talking to the Commission about whether this could be included in reference period five (RP5) of the EU Performance Scheme; what could be done to incentivise ANSPs to optimise their CNS systems earlier than planned.”

The CNS Evolution plan development also affects stakeholders other than ANSPs.

“Our timeline is aligned with the Master Plan 2045, so it will also help States and industry understand what systems will need to be supported over what timeframe and what the future market demand will be,” said Predrag Vranjkovic. “We had the first CNS industry round table in Toulouse hosted by Airbus last year, where we gathered together representatives from the CNS industry – ground, airborne and space segments – and I was surprised at how far they had progressed their plans for a digital ATM marketplace.”

The move from supplying hardware to ANSP customers to services is already underway in some States, with industry owning and supporting the infrastructure and providing services to ANSPs within service level agreements which include key performance indicators.

There is also an important human dimension to the provision of more digital systems. The EUROCONTROL CNS PM team is coordinating closely with controllers and engineers in technology development, with the support of the Expert Group on the Human Dimension of the Single European Sky (CEGHD), which includes all the personnel groups impacted by Single European Sky technology introduction.

The CEGHD’s role is to facilitate cooperation and coordination between the Commission and relevant stakeholders on questions relating to the implementation of EU legislation and ensure an exchange of expertise, experience and good practice among members as regards the human dimension of the Single European Sky.

“We need to bring them on this journey because if we do it without them it's not going to work,” said Predrag Vranjkovic.

ATM CNS evolution planning also has to take account of the European Commission's commitment to environmental improvements within its Green Deal policy, the inclusion of artificial intelligence and spectrum and bandwidth resources.