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SES 2+ Regulation: ATC charges and the environment

By  Brussels, — Last updated on 11 December 2023


The current regulation concerning the Single European Sky (SES) was published in 2009 as Single European Sky II or SES II. By 2013, it was more than obvious that an overhaul was necessary. A subsequent SES 2+ was discussed — but never finalised. On 22 September 2020, the European Commission finally published its view on an updated SES regulatory framework that could achieve the original SES targets on CO2 emissions reductions, a reduction in delays and an increase in the cost efficiency of the ATM service provision.

The current SES 2+ draft introduces a link between ATC charges and political ambitions to achieve a reduction in CO2 emissions. Whilst decarbonisation is a key goal of the aviation industry, incentives of any form should target issues that are under the control of those being incentivised. Here, airlines are directed to use modern equipment and ensure fuel-efficient trajectories. The first is within the airlines’ abilities – the latter is not.

The proposed SES 2+ draft regulation is written primarily to ensure (airspace) efficiency by states and Air Navigation Service Providers (ANSPs). In addition, sustainable aviation fuels (SAFs) are linked to the modulation of ATC charges. Since the availability and possibly mandating of SAFs is not part of SES but is handled within other regulatory files, the link between ATC charges and other political ambitions needs to be severed.


A fully implemented Single and Digital European Sky (SES) is key to maintaining safety once traffic grows again. It will also be instrumental in reducing aviation’s environmental impact and CO2 footprint – supporting the European Green Deal. An updated SES regulatory framework must not only facilitate a transition to a clear future vision but also include strong incentives and clear targets to push the responsible parties – EU Member States – to increase the efficiency of the ATM system and thus positively contribute to these environmental targets.

As such, the draft SES 2+ proposal is based on the 2013 draft regulation and more recent analyses, including the Wise Persons Group (WPG) report, the joint ATM Stakeholder Declaration as well as the ATM Masterplan. The latter two documents, in particular, highlight CO2 reductions, environmental benefits as well as digitalisation as the three driving forces behind the SES 2+ update.


The current SES 2+ draft introduces a link between ATC charges and environmental political ambitions. Of specific concern is the link to the uptake of sustainable aviation fuels (SAFs) and “fuel efficient trajectories”. The idea is to incentivise airlines to buy more SAFs and burn less fuel to create a net reduction of CO2.

Do we think this is within the scope of the regulation?

Historically, the idea of a single European sky was linked to technology. Consequently, the research and deployment activities that took place under SES I, SES II and also outlined in the SES 2+ draft regulation focus mainly on technical and operational improvements. Other activities, such as SAFs or alternative means of propulsion are dealt with in other specific regulations and instruments, such as “Clean Sky” and blending mandates. Regarding “fuel efficient trajectories”, there are other instruments to reduce CO2 emissions, including CORSIA or ETS. SES 2+ should therefore refrain from mirroring these activities and instead support technical and operational measures that can deliver emissions reductions.

Are ATC charges an effective means?

Incentivising desired behaviour through pricing schemes is a commonly used practice. Unfortunately, such pricing schemes are sometimes used without ensuring that the desired behaviour can be accommodated, e.g. urging citizens to use public transport without increasing frequencies or connectivity. The current proposal it’s about incentivising the use of SAFs without SAFs being available in sufficient quantities.

Several programs and initiatives aimed at finding new ways to increase SAF production exist, but they also show that there will not be enough SAF available for aviation use in the coming years. Consequently, modulating ATC charges to incentivise SAF uptake overlooks a fundamental ingredient – the availability of SAFs.

The second idea of the regulation is to use charges to ensure fuel-efficient trajectories. Again, this ignores a fundamental ingredient – an airspace that allows airlines to actually plan and fly these trajectories. The so-called free route airspace required to allow airlines to fly preferred trajectories will not be implemented on a European scale in the next years.

Today’s airspace is simply not designed in an efficient manner (see results of the SJU Airspace Architecture Study Adding capacity/demand discrepancies into the mix — an excess fuel burn of around 10% impacted our environment in 2019SES 2+ Staff Working Document: Necessary changes need to be performed by states and their Air Navigation Service Providers (ANSPs), who should be effectively incentivised via the economic regulation handled by the new Performance Review Board.

As such, linking ATC charges to environmental targets as outlined in the current draft regulation incentivises the wrong targets – airlines that do not have the ability to change or implement the fundamental quality of airspace efficiency.

What needs to be done?

Before trying to change a behaviour, an alternative must be available. In the case of airlines, this means a more efficient airspace is required, providing the capacity necessary to satisfy the demand. In the short term, this can be done with national measures and airspace improvements, but airspace allowing user-preferred (fuel-efficient) trajectories must be the ultimate goal.

This goal should not be hindered by national interests, concerns about data sharing, or interoperability of systems. The SES 2+ regulation must support this objective and include the principles and mechanisms helping states and ANSPs to introduce new paradigms, and new investments and to facilitate work across national borders.

A word of explanation

The below graph shows two trajectories developed under the different scenarios, one SES 2+ would require fuel efficiency and one based on the current paradigm of minimum physical distance between two points (great circle distance):

  • Scenario 1 – Red routing

–  Target: Minimum Deviation from Great Circle Distance (ground distance 1361 NM)

–  Resulting in fuel burn of 7632kg

  • Scenario 2 – Blue routing

–  Target: Minimum Fuel Burn (Ground distance 1393NM)

–  Resulting in fuel burn of 7493kg


Creating a target based on the Great Circle Distance and connecting it to ATC Charges incentivises the wrong behaviour. In the above example, airlines would burn an additional 139kg of fuel and emit 438 additional kg of CO2 – just to be compliant and to avoid additional payments.

This example is not the exception – only under very specific (weather) conditions, is the shortest route also the most fuel-efficient one. Adding different constraints, e.g. capacity shortages or closure of airspace for military training activities into the mix, identifying the most fuel-efficient route becomes even more complex and requires sophisticated software.

The calculations required on the ANSP or EUROCONTROL side to correctly calculate what to charge airlines will be even more complex as they do not have the capabilities to identify if the route planned, and flown, is the most fuel-efficient one (based on aircraft type or actual aircraft weight). Using Great Circle Distance is a compromise that ignores the fact that this route does not represent the most fuel-efficient route.

This short example highlights that the existing Key Performance Indicators (KPIs) used in the EU Performance and Charging Scheme need to be re-defined to support the Green Deal.


The current SES 2+ draft regulation aims at increasing the efficiency of the aviation system (i.e. service delivery and airspace efficiency via digitalisation). In an attempt to support the Green Deal, it introduces a link between ATC charges and a reduction of CO2 emissions. Reduction of emissions is a long-standing and fully recognised goal of the aviation industry which does not need further pushing. Using all available possibilities to reduce operating costs in a very competitive market is crucial for businesses to survive.   Hence, airlines are very much interested in seeing the digital single European sky implemented and the single aviation market completed. Both would provide ample opportunity to increase efficiency – namely airspace efficiency – and thereby reduce the environmental footprint of air traffic. If this environment is established, airlines can plan and fly more fuel efficiently – until then they lack the ability to do so.

The current SES 2+ draft is an opportunity to reach the original SES goals of reducing aviation’s environmental impact, minimize ATC delays, improving the cost-efficiency of the ATM service provision and ensuring the completion of the single aviation market. Therefore, we recommend opening a discussion to clarify and focus on the ambition of the new SES2+ regulation taking the below into account:

  • Modulation of charges and common route charges: The effectiveness of these tools in incentivising the environmental behaviour of airlines should be assessed considering the competitive effects and known alternatives, e.g. “best equipped – best served”. Linking ATC charges with the use of sustainable aviation fuels (SAFs) does not have a direct impact on airspace efficiency nor does this support the original goals of the SES. In addition, SAFs are currently not available to all airlines.
  • Environmental benefit: SES 2+ addresses Air Traffic Management and should focus on increasing the efficiency of the system. This efficiency increase could effectively reduce CO2 emissions by up to 10% per year – starting now. The elements that do not bring a direct impact on airspace efficiency improvements, e.g. SAFs, should be left to other forums.