Editor's Note

Uniting Europe

By By George Marsh | June 1, 2010
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A vision that underpinned the formation 50 years ago of Europe’s multi-national air traffic control agency, Eurocontrol, was that one day there would be a Single European Sky (SES) instead of a fragmented, multi-faceted airspace structured around national boundaries. This vision has not yet materialized, although it is getting closer to realization.

Eurocontrol and the European Commission (EC), the executive body of the European Union, now have an air-traffic management (ATM) roadmap for more than doubling system capacity by 2020 while also enhancing safety and operational efficiency. Additionally, the plan should cut fuel usage and emissions by enabling aircraft to follow not just direct routes but ideal four-dimensional trajectories, dubbed business trajectories, extending from gate to gate.

Ideally, there should be a single seamless European airspace, controlled from just two or three “super” ATC centers. But more feasibly, the plan is first to rationalize existing airspace into functional airspace blocks (FABs), each covering a number of national jurisdictions. This would be an important step away from the one airspace/one ATC organization per country model that has resulted in the present fragmented system. As a result, costs for airspace users should be reduced to something more akin to those in the United States, where a single federal airspace operates more efficiently than the present European model.

For many years, the reluctance of nations to cede ATC sovereignty to an international authority stalled the SES vision and obliged Eurocontrol and others to concentrate instead on harmonizing the continent’s diverse ATC structures and procedures. But conditions in the late 1980s, when burgeoning air traffic hit capacity buffers, causing congestion and delays throughout Europe, led to a change of heart. As air-traffic management all but broke down under the strain, it became evident that having aircraft dogleg around the boundaries of some 40 countries using dated ground-based navaids, with procedural ATC handovers each time an airspace boundary was crossed, was no longer tenable. It was time to replace a system rooted in the 1960s with one fit for the 21st century.

The EC established the Single European Sky program in the 1990s. This was followed by the launch of the SES Implementation Program, in the first instance by ATM equipment manufacturers. As the new millennium dawned, Eurocontrol unveiled its comprehensive ATM 2000+ plan. The agency previously managed the European ATC Harmonization and Integration Program, which was a driver for the central flow management unit that helped facilitate en-route flows from the late 1980s and has since helped drive system capacity enhancements including BRNAV, RVSM, CPDLC, ARTAS and 8.33 kHz VHF channel spacing. An aim of ATM2000+ was to achieve levels of convergence and interoperability sufficient to give airspace users the impression of being served by a single system.

By now, the EC was aiming for a wholesale transformation encompassing regulatory, institutional and technological change. In its SES 1 legislative package, adopted in 2004, the commission targeted various changes, including airspace rationalization achieved via the formation of FABs. But impetus toward these FABs was still lacking, so effort had to be concentrated on areas where progress was possible. Policy makers were determined that any program had to be performance led, rather than technology led, as had tended to be the case hitherto. Accordingly, performance requirements for communications, navigation and surveillance were identified, while a master plan for further action was formulated, this being officially adopted in 2009.

Last year, the EC launched its follow-on SES II package and, given the weight of political commitment and legislation now behind it, along with legally binding targets, this has re-kindled hopes of progress on all fronts, including airspace.

Six years ago, the morphing of SESAM into the Single European Sky ATM Research (SESAR) program gave a boost to the major R&D effort that is needed if Europe’s ATM targets for 2020 are to be met. SESAR is, in fact, the vital technological pillar of the SES vision.

SESAR, a coordinated approach intended to replace the fragmented research that prevailed before, is being undertaken in three phases. Phase 1, Definition, determined what work and resources would be needed to modernize European ATM and came up with a master plan for further action (accepted in 2009). This phase was completed in 2008, making way for the second, Development phase, currently in progress. The third phase, Deployment, which is expected to follow from 2016, should see fully implemented the defined and developed changes to the ATM infrastructure, along with the necessary legislation and regulations.

The SESAR task is complicated by the need to comply with ICAO’s over-arching ATM Operational Concept, thus ensuring compatibility with NextGen in the United States and other regional ATM initiatives, and to be interoperable with legacy avionics and ground equipment that will be in use for years to come. Then there is the important need to engage all stakeholders.

To fulfill these requirements, the current Development phase is being led not by a single contractor or agency, but by a collaborative Joint Undertaking (JU). The SESAR JU, formed in 2007, is a public-private partnership that includes members ranging from industrial participants to Eurocontrol, which is managing the work program, and the EC.

Patrick Ky, executive director of the SESAR JU, argues that this form of organization is essential to ensure maximum “buy-in” from all stakeholders airspace users, operators, the ATM community, the military, flight crews, airports, research organizations, equipment manufacturers, policy makers and governments.

Justifying the JU as well as Eurocontrol’s leadership role, he said: “We have witnessed the incredible amount of energy needed to coordinate at a European level the implementation of a common program. We have to build a ‘working together’ culture in which Eurocontrol is seen as a key partner and not just an inter-governmental organization. SESAR was launched because all stakeholders realized that the status quo would endanger the sustainable growth of air transport which is vital for European society.”

The €700 million R&D program has been broken down into some 300 projects arranged in 16 work packages, five of which are being led by Eurocontrol. Project examples include WP7, which focuses on managing aircraft flows across Europe; WP9, concerned with aircraft systems and WP15, CNS systems, the latter two being of particular relevance to avionics. Other system development activities are covered by WPs 10, 11, 12 and 13.

Among high-level work challenges are the design of a new European route network, the coordination of scarce resources, including frequency bands and radar transponder codes, plus the necessary ongoing update of the ATM Master Plan as the system evolves.

SESAR’s Progress

Since SESAR came into being in June 2009, there has been significant progress. The first 30 SESAR projects were launched almost immediately, in July that year. Among these were three addressing the future aviation intranet, wireless ATM communication at airports and a satellite-based precision landing system.

Some €2 billion worth of contracts was signed during the summer with industry and air navigation service providers. By the end of the year, 125 projects were underway and as of March this year, the total stood at 150 projects involving 1,400 contributors.

Wide ranging expertise is being brought into the program. Last September, the SESAR JU signed contracts with several major European airlines and representatives of business aviation to engage their technical experts. Eric Platteau, SESAR’s chief communications officer, noted that airspace users are a heterogeneous group with different needs, and it is important to have their views accommodated as new systems and processes are developed. Expertise from other areas, including flight operations and planning, avionics specification, network management and training, also is enlisted. About 70 companies are involved.

With longer-term research in view, Eurocontrol recently launched a first call for research networks to participate in work package E, which aims to build a significant ATM research capability in Europe. Such networks will bring academia, research establishments and industrial partners together in joint research projects.

More immediately, to maintain stakeholder engagement, the SESAR JU is aiming for early delivery of “low-hanging fruit” — results that can be obtained quickly and with minimal investment, using technology that already exists.

Bernard Miailleur, a senior Eurocontrol official, said initial results should be revealed as early as this year, with “value-added packages” being delivered at an increasing rate thereafter. Research needed to clear the way for time-based operations (Service Level 2) is expected to be completed by 2012, followed by trajectory-based operations (Service Level 3) by 2014 and performance-based operations (Service Level 4) by 2016.

Europe’s interim measure to achieve a more dynamically structured, efficiently managed airspace, known as Dynamic Management of the European Airspace Network (DMEAN), is helping pave the way. Now part of the first SESAR implementation package (IP1) as defined in the European ATM Master Plan, DMEAN has existed since 2006 and targets quick-fix capacity gains that do not require new technology. It aims to streamline flight planning, airspace design, civil/military coordination, airspace management and other activities, often at the local level. Significantly, it includes airport operations, recognition that air traffic flow improvements will be of no avail unless airport capacity increases too.

Accordingly, from this year, there is a strong focus on terminal airspace, runway capacity, stand capacity and ground movements, to balance the ongoing emphasis on en-route operations.

To provide the necessary communications system that all operational agencies can use, a network of datalinks dubbed the Pan-European Network Service (PENS) was implemented last year. PENS is an Internet Protocol (IP) enabler intended to link the entire European ATM system, with information able to be shared throughout for the first time.

According to framework program activity manager Chris Bouman, DMEAN is on schedule, having already significantly reduced en-route delays and increased capacity by an estimated 3 percent in the last three years. It is difficult to quantify the improvement precisely, Bouman said, because the reduction in air travel brought about by the recession has disrupted previous trends, making interpretation complicated.

In a move that presages the intended free-routing future, direct user-preferred routes are being allowed in certain areas where traffic density is low, for instance over Scandinavia and in the upper level approaches to transatlantic tracks over Ireland. While the present human-centric system precludes extension of this practice to more central regions where traffic is dense, as SESAR enables the ATM system to become more automated, more flights will be able to follow optimum business trajectories.

Projects expected to make significant progress this year include validation of advanced approach procedures with vertical guidance in Spain, Italy and Norway and further progress on the joint European Union and FAA Atlantic Initiative to Reduce Emissions (AIRE).

In terms of airspace rationalization, nine groups of countries are negotiating ATM alliances and likely new airspace blocks. These include, for example, those intended by the U.K. and Ireland, Spain and Portugal, Denmark and Sweden, a Mediterranean block plus a crucial FAB encompassing the congested core airspace over Belgium, France, Germany, Luxembourg, the Netherlands and Switzerland. Field trials held late last year of this central Europe FAB should lead to a single airspace across this critical area, facilitating flow and more direct routings. FABEC will include the existing Maastricht Upper Air Control Center, which was the world’s first truly international ATC facility. The scope of FABs is being extended into lower airspace.

Alex Hendricks, Eurocontrol deputy director of network development, fears that not all of these FABs will be ideal since they may still owe as much to political partitioning as to regional needs based on actual traffic flows. Nevertheless, a reduction from more than 27 individual airspaces (“more than” because there are 27 European Community states but some 46 countries across Europe) to nine, with commensurate reduction from several dozen area and sector control centers, looks like progress. Under the SES II roadmap, late 2012 is a firm deadline for the introduction of FABs throughout Europe, though this seems optimistic.

There also is provision under SESAR to improve civil-military coordination. Flexible use of airspace, a doctrine under which the military gives up previous exclusive rights to portions of airspace so that civil and military authorities can share it collaboratively, has been in force since the 1990s, but the way the rules are applied has varied between jurisdictions.

Experience during the Balkans conflicts, particularly over Kosovo, showed that such arrangements can work, but fresh accommodation will be needed as SESAR transforms ATM infrastructure. Initially, work is continuing to harmonize coordination rules throughout Europe.

Among future tasks, SESAR will have to establish that flight management systems used in civil and military aircraft can both exchange information with systems on the ground when 4-D trajectories are being generated.

Environmental issues are another field addressed by SESAR. The SESAR JU and FAA jointly announced at ATC Global in Amsterdam in March results from the AIRE program. Recent trials have involved, on the European side, 18 partners executing more than 1,000 commercial flights. “Green” climbs and approaches were conducted at the Madrid, Paris and Stockholm airports; ground movement trials took place at Paris Charles de Gaulle airport; and tests for green oceanic procedures were undertaken in Santa Maria, Portugal, and Iceland. Direct routing and variable speed flights also featured.

Linking these trials provided a full gate-to-gate overview. Using improved procedures with technology already available, AIRE demonstrated CO2 savings from 90 to 1250 kg per flight, and accumulated savings of 400 tons of CO2.

Most of the solutions tried are already in operation and, once introduced more widely, will achieve significant total fuel savings and emissions reduction.

Technology Needs

Some of the technologies needed to support future European ATM already exist and require only refinement and integration; others will have to be developed. A prime role of SESAR is to ensure that all of these are in place and harmonized throughout Europe.

As voice communications become increasingly inadequate in congested airspace, there will be greater reliance on data links for air-ground communication. The Controller-Pilot Datalink Communications system implemented under ATM2000+ has been extended under Link 2000+. Using Aeronautical Telecommunications Network and VHF Digital Link (VDL Mode 2) technology, this automates ATC clearances, communications management and microphone checks, tasks that account for up to 50 percent of controller activity. Capacity for voice traffic, still used for non-routine communications, was increased by the reduction in VHF channel spacing from 25 to 8.33 kHz. First mandated for airspace above FL245, this is now being extended to airspace below FL195.

Satellite communications will have a growing role in ground-air communications, initially for the passengers but could also serve controllers and pilots. On the ground, Air Traffic Service (ATS) voice networks will rely on voice over Internet Protocol technology (VoIP) to support a ground intranet that facilitates sharing of multimedia data.

A combination of advanced communications and surveillance will bring about a radical transition in ATM whereby pilots and controllers can share situational awareness so that collaborative decision making becomes possible. Management by trajectory will involve the sharing of information on future positions of aircraft as well as current positions.

In the surveillance domain, as secondary surveillance radar (SSR) reaches the limits of its operational capability, Mode S Elementary Surveillance has become a familiar feature of European air transport. However, users will soon be encountering Mode S Enhanced Surveillance (EHS), first deployed in the Czech Republic, Hungary, the Maastricht center and the U.K. EHS enables controllers to see pilots’ selected altitude, magnetic heading and indicated speed, as a check on compliance with ATC instructions and against mis-selection on the flight control unit. Mode S also makes it possible to overcome a shortage of available SSR identification codes and identify aircraft more clearly. Looking ahead, implementation of ADS-B and multilateration will complement radar, at the same time reducing reliance on expensive ground-based radar infrastructure.

Navigation will be increasingly satellite based, though with a suitable ground-based back-up such as inertial, DME or advanced LORAN. Coverage, accuracy and safety will be augmented by additional satellite constellations including Europe’s Galileo, now in development. This will permit ground beacon-based navigation to be phased out, enabling more flexible use of airspace without confining traffic to “aerial motorways.”

Required Navigation Performance (RNP) based avionics and procedures will facilitate precise navigation, especially in terminal areas, so that separations between aircraft can be reduced and airspace capacity increased. Satellite-based landing systems, possibly with enhanced and synthetic vision systems, will reduce diversions and delays in poor visibility.

SESAR will support the further integration of communications, navigation and surveillance so the ATM system can manage trajectories in the three spatial dimensions plus time (4D), in all operational stages from gate to gate. Flight management systems, already highly capable on the latest aircraft, will be further developed to support such trajectories.

A harmonized set of ATC automated support tools monitoring aids, conflict detection tools and others will help controllers, further assisted by new procedures, to handle more traffic. Ground-based safety nets, analogous to the Airborne Collision Avoidance and Enhanced Ground Proximity Warning safety nets in aircraft, will be refined and supplemented to provide multi-layered protection in dense traffic environments.

SESAR faces extra challenges due to the current recession. There were 6.6 percent fewer flights in 2009 than in 2008, the largest annual decline on record. This eases air traffic congestion, which could possibly dilute the perceived imperative for change, and puts pressure on funding.

Now, even more than before, airspace users will want to minimize investments that do not achieve early returns. With tight budgets in mind, they will seek to minimize requirements for new avionics, preferring software upgrades to existing equipment where possible. They will be interested in solutions that are operationally driven, and will want interoperability with other regional solutions.

But, given that all stakeholders have accepted the need for change, most are backing SESAR as the research instrument for achieving a coordinated and orderly transition to a new ATM infrastructure for Europe.

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