The temporary collapse in air traffic as a result of the COVID-19 pandemic offers Europe a once-in-a-lifetime opportunity to accelerate air traffic management (ATM) modernisation. Before traffic returns, however, policymakers need to ensure that Europe’s skies are fit for the digital age. Aerospace Tech Review talked to industry body CANSO to find out what is on the horizon as well as what is emerging in the longer term as the United Kingdom and European Union look to improve safety with the development of new mandates and regulation.

Ensuring that complementary technologies critical to the digital transformation of the air traffic management industry will meet the needs of the industry has been one of the chief concerns for the Civil Air Navigation Services Organisation (CANSO), the voice of the air traffic management (ATM) industry. Comprising air navigation service providers and suppliers from around the globe, the association’s mission is to transform ATM performance. CANSO ensures the industry is fit for the future by identifying trends and new technologies, sharing best practice, providing guidance and training, and influencing policymakers across the world. This is particularly important during the present time, as the industry works together to navigate a new normal, and a new era for aviation.

Andrea Gartemann is a senior expert in EU regulations working at German air navigation service provider DFS Deutsche Flugsicherung GmbH and as co-chair of CANSO’s EASA Task Force is involved in many of CANSO‘s activities at the European Commission level. Here she shares her perspective on how the industry is tackling restart and recovery and building resilience – focusing not only on ‘the now’ but ultimately the ‘what next’.

“In safely navigating the industry’s COVID-19-recovery,” Gartemann says, “a look at the horizon will depict the most critical challenges and opportunities ATM is facing.”

Andrea Gartemann, Senior Expert EU Regulations, DFS Deutsche Flugsicherung
Andrea Gartemann, Senior Expert EU Regulations, DFS Deutsche Flugsicherung

Safely Navigating the Industry COVID-19 Recovery

As the industry continues to work on assessing how best to manage the COVID-19 recovery, CANSO has reaffirmed its commitment to working towards and achieving the “Digital European Sky,” insisting that this vision is still valid, and that progress and plans made so far remain important for the digital transformation of the industry.

CANSO believes the Single European Sky (SES) and its research and development initiative Single European Sky ATM Research (SESAR), must be kept sufficiently stable. However, as Gartemann points out, at the same time the European modernisation effort must provide enough flexibility to accommodate the current exceptional situations. Within the framework of digitalisation, a re-assessment of the priorities seems unavoidable therefore and in general terms as a guiding principle, that means a shift from quantity to quality of output. CANSO believes that priority should therefore be given to measures that allow stakeholders to emerge from the crisis (e.g. mature SESAR solutions targeting flight efficiency, rationalisation of infrastructure, etc) while other activities to create capacity in the very short term are no longer as important as originally planned, and could even be deferred. This would allow for other activities that could generate economic support for the industry to be prioritised.

The Common Project (CP1)

Only recently, in February 2021, the European Commission updated the former ‘Pilot Common Project’ and pushed the industry for a ‘Common Project 1’ (CP1). CANSO supports the main goal of this regulation with its general principle of generating greater and earlier benefits for the European air traffic management network through synchronised deployment. Hampering the ambitious and strictly scheduled nature of the individual projects, however, is the pandemic. Acknowledging the uncertainty surrounding how the COVID-19 pandemic will develop, CANSO underlines the importance of adopting a flexible and progressive approach proportionate to the improvement of the public health crisis. “We should remain vigilant of the risk of further outbreaks and plan accordingly,” says Gartemann who adds that a major element for future preparedness will involve analyzing insights and experience gained from this crisis.

The ATM functionalities that make up the Common Project are heir to decisions taken within SESAR years ago to tackle capacity issues that have today lost relevance due to the pandemic. This has combined with a high level of uncertainty surrounding the impact of COVID-19 in industry stakeholders’ plans. An updated cost benefit analysis of the Common Project issued in February 2020 by the SESAR Deployment Manager demonstrates the uncertainty through flagging a 50% drop in revenues by 2030. According to a EUROCONTROL five-year forecast in the most likely scenario, a recovery to 2019 traffic levels is not forecast before 2026. “This means that stakeholders will have to make the investment effort for the deployment of CP1 exactly in the period of traffic recovery and it is currently too optimistic to consider that all stakeholders will be able to cope with these strong counter-cyclical investments,” says Gartemann.

Air-ground datalink communications is an area of special interest to CANSO. Schipol Tower shown above.
Air-ground datalink communications is an area of special interest to CANSO. Schipol Tower shown above.

The challenge of data link communications

CANSO sees the mandate for air-ground datalink communications supporting the downlink of data to enable earlier and more accurate flight profile prediction as a subject of special interest.

The CPDLC — controller pilot data link communication — application provides air-ground data communication for the ATC service to exchange clearance/information/request messages which correspond to voice phraseology employed by ATC procedures. Expected benefits range from reducing radio transmission loading on ATC frequencies, reduction in air traffic controller workload, increased sector capacities, reduced probability of miscommunication and more reliable handover of sectors/frequencies information. Global implementation is currently at different stages of implementation however.

Here, Gartemann explains that despite the European datalink mandate, which was first introduced in 2013 through Regulation (EC) 1207/2011, equipage rates both on ground and in the air have not developed as expected and technical issues have reduced the availability of datalink for ATC use. Collaborative technical investigations involving the whole community of stakeholders from ANSPs to avionics manufacturers and airlines have been commissioned in order to improve the issues. “The equipage mandate had been postponed to the year 2020, too,” she says. “This, in the end, has all led to a coordinated approach.”

Indeed, all the stakeholders together with the European Aviation Safety Agency (EASA), the SESAR Deployment Manager and the Network Manager continue to meet, update, discuss, exchange and contribute to gain progressively the expected benefits of CPDLC in order to pave the way to enable new concepts of operation with datalink services (DLS) an important enabler for Trajectory Based Operations (TBO) concept in particular.

One of the technical challenges has been the longevity of the key ground infrastructure used to support datalink, VDL M2. This infrastructure supports other non-ATC data link services namely Airline Operational Control (AOC) as well as Air Traffic Services (ATS). Both ATC and AOC data traffic levels are steadily rising through increased use and increased digitalisation of aircraft and therefore it is not a question of if, but when, VDL2 will become congested when air traffic volume picks up pace again. And, as important side note, Gartemann points out, more radio spectrum for additional VDL M2 channels would not be available without e.g. 8.33 kHz air ground investments in offset carrier operation; while of greater relevance is the fact that the VDL M2 channel access scheme does not allow for time critical tactical ATC messages. This congestion will not only limit the achievable DLS performance and consequently reduce the efficiency and effectiveness in the operational ATM network but will limit the expand for use for ATC as well. A report on DLS architecture and deployment strategy drafted by the SDM and submitted to the European Commission calls for “the need to support the implementation of the complementary communication technologies as soon as possible, offloading the VDL M2 channels.”

The temporary collapse in air traffic as a result of the COVID-19 pandemic has offered the EU a once-in-a-lifetime opportunity to accelerate air traffic management (ATM) modernization. Before traffic returns, however, policymakers need to ensure that Europe’s skies are fit for the digital age and address the capacity constraints that have led to congestion, flight path inefficiencies and unnecessary fuel burn over the last decades. Some complementary technologies have already been identified in all European Framework funding programs to avoid future congestion and which complement VDL2.

It will be imperative for policymakers to address the capacity constraints that have led to congestion, flight path inefficiencies and unnecessary fuel burn before traffic returns to pre-pandemic levels. Edinborough Tower shown above.
It will be imperative for policymakers to address the capacity constraints that have led to congestion, flight path inefficiencies and unnecessary fuel burn before traffic returns to pre-pandemic levels. Edinborough Tower shown above.

LDACS (L-band Digital Aeronautical Communications System) is the future terrestrial data link for aviation currently undergoing ICAO standardization. LDACS technology is based on modern, well-proven state-of-the-art technology as applied for LTE/4G mobile radio. It is a secure, scalable and spectrum-efficient high-rate data link designed to cover both ATS and AOC services. It is a cellular communications system and, thus, avoids co-channel interference problems as experienced in current VHF communications. It will provide support for ATN/B1 and ATS/B2, and is further expected to cover ATS/B3 as well as additional future services. These capabilities will underpin advanced ATC concepts for the future, e.g. ‘sectorless flying’ including full 4D TBO and flight-centric air traffic management. Trials have proven LDACS as capable for navigation support functions and voice communication, too.

Complementary technologies, like SATCOM, also support the current air ground datalink infrastructure, providing the necessary total capacity. They also meet the required performance for ATN/B1 and ATS/B2, providing the opportunity to extend the horizon of CPDLC and ADS-C operations, extending its service coverage to enable the effective exchange of data with aircraft.

CANSO supports the view that both technologies, LDACS and satellite systems, have their specific benefits and technical capabilities which complement each other. Satellite systems are especially well-suited for large coverage areas with less dense air traffic, e.g. oceanic and remote regions. LDACS is well-suited for dense air traffic areas, e.g. continental areas or hot spots around airports and terminal airspace. It is expected that LDACS together with upgraded satellite-based communications systems will be deployed within the future communication infrastructure and constitute the main components of the multilink concept within that infrastructure.

Contributing Factors: Incentives and Coherent Deployment

Regulatory and financial incentives are necessary to secure and accelerate not only the deployment of satellite-based data link services before air traffic volume returns to pre-COVID levels. It is urgent to define a coherent deployment plan for sustainable datalink services in the mid- to long-term. The Common Project regulation (CP1) establishes the mandated services to modernize ATM. “We should anticipate those deployments that support the goals of the Single European Sky, in terms of efficiency, capacity, etc,” says Gartemann, who adds that clear guidelines must be put in place and specific funding to support the implementation.

CANSO says the current CP1 proposal does not include a plan for the coordinated air and ground deployment of data link services and that furthermore, the deployment plan urgently needs to address the concept of multilink for the combined operation of SATCOM and/or LDACS with VDL, both on the ground and through the configuration settings on the aircraft. Today, this is a fundamental gap which presents a significant obstacle to the introduction of complementary technologies and yet it is not ‘owned’ by any organisation through to an agreed conclusion.

Iris SATCOM is ready to be deployed and has secured widespread support although CANSO believes a subsidy supporting Iris services should be put in place by the European Commission for both air and ground adopters, otherwise ANSPs may be forced to reject Iris services for the foreseeable future. Consideration should be given to the fact that a new CNS technology will also need to be provided on a pan-European basis by an SES-certified service provider. This will be the case for Iris and while this may be seen as costly it will be an important venture to underpin the effectiveness, safety and compliance of service provision. CANSO here says it is strongly preferred that the European Commission deals with this largely technology-centered problem in careful consideration of the context, including sustainable use of spectrum, the cost of implementation and any regulatory and financial incentives as appropriate.

The establishment of a common European Datalink Service Provider (DSP) will further harmonize datalink provision and governance for Europe. DLS users are now successfully collaborating towards the establishment of such a common provider entity initially through an initiative known as CoDE[A1] project (Common DLS governance for Europe). CANSO says it supports this effort, as the presence of the DSP is the necessary prerequisite to ensure that required service performance will be systematically met while at the same time allowing for the effective coexistence of multiple commercial actors in DLS provision; this will achieve cost efficiencies for the ANSP community in modernizing datalink.

Equipping a segment of the European aircraft fleet is a long and costly process. In addition, the operating cost of a satellite-based service requires consideration. In the absence of a regulatory driver and associated incentives, CANSO says it is unlikely that airlines and ANSPs will be motivated to start investing in the technology. The consequence would be that a critical mass of aircraft equipped with this alternative technology will not exist at the point when the VDL2 may collapse.

COVID-19 has put an immense financial strain on the aviation sector. Member states have designed rescue packages to provide relief while the EU has agreed on a comprehensive recovery facility to accelerate the green and digital transformation of the economy. CANSO says it is the decrease of traffic that is bringing temporary relief to the ATM network but that it also provides an opportunity to accelerate the ATM modernization within an EU regulatory framework that will strengthen the long-term resilience of ATM.

The pandemic-induced decrease of traffic is bringing temporary relief to the ATM network, but it is also providing an opportunity to accelerate ATM modernization. Adnan Menderes Airport in Izmir, Turkey shown above.
The pandemic-induced decrease of traffic is bringing temporary relief to the ATM network, but it is also providing an opportunity to accelerate ATM modernization. Adnan Menderes Airport in Izmir, Turkey shown above.

Future Data Link Communications

On future data link communications, CANSO stresses the need to:

* Encourage early adoption of a modern communication infrastructure taking the advantages of both satellite-based navigation, communication and surveillance equipment and processes as well as of LDACS as a sub-network of the Aeronautical Telecommunications Network

* Consider the successful establishment of a user-governed Datalink Service Provider as a necessary prerequisite for the implementation of new and alternative communication technologies

* Establish increased cooperation and full alignment between the aviation sector and policy makers and regulators. EU and national funding frameworks should be adapted to accelerate the implementation of co-financing measures for fleet renewal (EU Green Incentive Scheme)

* Increase the public co-funding rates for Civil Aviation Research & Innovation (Clean Aviation and SESAR with 100% public funding for the deployment of SESAR technologies with proven sustainability and environmental benefits to finally accelerate the digital transformation of the industry.

Surveillance Service Booster ADS-B

Gartemann explains that while the introduction of complementary communications technology will contribute to alleviate spectrum congestion, a complementary surveillance technology can both support the rationalisation of infrastructure as well as overcome congestion of the 1030/1090 MHz channel, reserved for the interrogation and transmission of aircraft related position data. In parallel to infrastructure considerations, new performance targets and associated operational requirements are emerging from Single European Sky and SESAR initiatives. These factors will drive changes to the existing surveillance system. This evolution needs to be managed, for it will also be influenced by an extensive range of other factors such as global interoperability, civil-military coordination, cross-border operations, and the growing fleet of unmanned aircraft systems. Furthermore, cost and radio frequency spectrum efficiency considerations will lead to a rationalization of the current infrastructure, in which legacy systems will be phased out as soon as practicable and new, more efficient technologies will be introduced. Surveillance systems are a key enabler of any future operational concept and they are expected to be leaner and more efficient in the future.

The goal is focused on achieving safety and service continuity objectives by combining a layer of ADS-B with a layer of secondary surveillance (provided by either SSR Mode S or WAM). Primary radar coverage will also be available, where required (e.g. for safety or security reasons), either by classic (mono static) PSR or possibly in the form of multi-static PSR (MSPSR). The combination of technologies should be individually chosen by the ANSPs regarding needs, cost efficiency and other relevant considerations. In addition to ground-based ATM surveillance, ADS-B will also enable the development of new airborne surveillance operational services including air traffic situational awareness, spacing, separation and self-separation. An aircraft’s ADS-B transmissions can be relayed to the ground via satellite and this will provide improved surveillance in particular in oceanic and remote areas, and will potentially in the future provide an additional layer of ATM surveillance over European airspace.

“The regulatory mandate has been discussed a lot,” says Gartemann, “and the airborne equipage dates have been postponed; clearer exemption rules have been introduced as well as EASA publishing acceptable means of compliance and guidance material.” She points out though that although the mandate does not contain any obligation for ANSPs to implement ADS-B capable solutions, an agreed deployment plan was established by the SDM and is being maintained continuously. Meanwhile, ADS-B implementation projects on the ground progress and demonstrate confident and promising figures in contributing to a real rationalization target.

To rationalize the surveillance infrastructure and reduce the overall cost in the medium term before 2035 through the implementation of ADS-B, it will be necessary to change the current equipment mandate. Significant cost reduction may only be achieved if layers of radar infrastructure can be reduced and replaced by ADS-B. Therefore, it is recommended that all aircraft requiring IFR and/or controlled VFR services have to be equipped with ED-102A/Do-260B compliant transponders — not only aircraft with more than 5.7 tons MTOW/or faster than 250 kts.

As the airspace structure within Europe is quite different, the airspaces in which ADS-B equipment is required may therefore differ from nation to nation. In general though, it can be said that mandates for ADS-B equipment will support the rationalization of surveillance infrastructure, where the carriage of transponders is required today and will also provide the potential of an overall layer of ADS-B surveillance – satellite, ground and/or airborne – coverage.

CANSO believes that the Commission should consider a funding program for the equipment of small aircraft, which are required to be equipped with ADS-B and to ensure that adequate and affordable equipment is available. This would facilitate the voluntary equipage of small aircraft with ADS-B and contribute to enhanced aviation safety. An additional benefit would promote ADS-B IN applications, which may in particular benefit general aviation aircraft through the provision of traffic awareness and may compensate for the additional cost of ADS-B installations.

The Future with Regulatory Mandates

“Unfortunately,” says Gartemann, “we can demonstrate that the expected performance gain is seldom achieved through specific enforcements, especially when it comes to air-ground related EU Implementing Rules, namely data link, voice channel spacing ‘8.33 kHz’ and surveillance performance.”

Regulation in CANSO’s view shall, where necessary, enable the synchronised implementation of interoperable solutions. Regulation should be designed to create the right incentives, create options and allow ANSPs to decide which path to follow. “But,” says Gartemann, “at the core is our industry commitment to good EU industry standards. Coordinated implementation roadmaps along agreed operational concepts are essential. Together as an industry and with the SJU, EASCG, SDM, Eurocontrol NM and EASA, we should make best use of existing instruments.”