Europe’s Single European Sky ATM Research (SESAR) project, according to its latest self-assessed progress report, “is proving to be a powerful catalyst in transforming Europe’s ATM network into a modern, cohesive and performance-based operational system.”
That might be news to airlines that operate in certain parts of the continent’s still-fragmented airspace, but some advances – such as better-managed arrivals at busy hub airports – are undoubtedly becoming visible in other areas.
Industry sceptics, meanwhile, are worried that the complexity of the technology and the difficulty of achieving the unifying objectives of SESAR projects among so many national air navigation service providers (ANSP) could cause the project to lose its way.
Arnaud Feist, president of the Airports Council Europe, reminds SESAR’s leaders what the project is all about. He says predictability is what passengers want, and the keys are collaborative decision-making and fully interoperable systems. The airlines, in the words of Association of European Airlines chief executive Athar Hussain Khan, say interoperability in Europe and globally is essential, because only a seamless system will deliver the efficiencies enabling them to operate predictably and at low cost.
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The European ATM Master Plan lays out key objectives, and it is against these that progress – or lack of it – can be judged. These objectives are: achieving traffic synchronisation, particularly in manoeuvring areas at busy terminals; ensuring airport integration into the total ATM system, and accelerating airport throughput; moving from passive airspace management to active four-dimensional (4D) trajectory management (three dimensions plus time); network collaborative management with demand and capacity balancing; conflict management and automation; and a system-wide information management (SWIM) network as the enabler for all of it.
The integration of airports into the total ATM system entails bringing the time between an aircraft landing and taking off again into the ATM equation, which previously was not considered an ATM issue. Part of this objective is to enable airports to process more traffic – Europe has a serious problem with capacity, especially at its major hub airports – but the other part is to integrate landing slots and take-off slots with planned 4D trajectories. A change in mindset a few years ago led to ATM planners talking about a total aircraft working cycle as being from cruise to cruise, rather than from take-off to landing or even gate to gate. More sophisticated aircraft ground movement control systems are just part of this.
The growing effectiveness of SESAR research, according to its leadership, is demonstrated by the European Commission’s decision to execute the first set of SESAR solutions that are considered mature enough for synchronised deployment across Europe in 2015-2020. This is the product of groundwork carried out between 2011 and 2014, in which 15 separate system validations were carried out in 68 local exercises. That process continues today.
The SESAR deployment phase that follows all the development and validation work will consist of a series of “Pilot Common Projects” managed by the recently established SESAR Deployment Manager. The manager directs an alliance of European ATM participants in partnership with the EC “…who will ensure that new technologies and solutions that have already been tested and validated through the SESAR joint undertaking are delivered into everyday operations across Europe”. These are so-called “SESAR solutions”, the successful operation of which in several locations will – hopefully – lead to adoption throughout the still-nationally-minded network.
One objective is to synchronise traffic, particularly in manoeuvring areas at busy terminals
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A scan of significant sites throughout Europe – airports and bases where the new solutions are being implemented or trialled – shows that the system more sites are implementing than any other is the initial version of the system-wide information management system (SWIM). This is encouraging, because when fully implemented SWIM will be the neurological network for the whole Single European Sky. It enables network-wide collaborative decision-making (CDM) that responds in real time to demand. Like a healthy body’s nervous system, SWIM should make the entire system react intelligently and responsively. As Eurocontrol’s ATM director, Philippe Merlo, says: “All ATM activities depend on information management.” This prime objective is recognised at International Civil Aviation Organisation level.
But every technology-dependent system fundamental, such as SWIM, also has human-related or culturally related layers. Even in a brilliant digital datalinking network receiving comprehensive information from all relevant sources, a standardised form of information presentation has to be agreed or it will not work. That is a major task in its own right.
SESAR involves so many parallel steams of activity during the present deployment phase that there is a need to maintain a wide-angle view of ATM advances. For example, all approved advances must adhere to agreed principles ensuring global interoperability, and research and development must be synchronised to ensure progress meets that objective. New solutions applied locally must be seen to adhere to agreed standards. The latter concern acknowledges that the national fragmentation that still bedevils the implementation of SESAR plans might still allow for individual operational interpretations of agreed new procedures. So standard operating procedures must be not only applied, but also centrally overseen.
Then there is the global perspective. The USA is implementing its NextGen ATM system, facing the same technological challenges but without the cultural, linguistic and geographical fragmentation. Between them, the systems that Europe and the USA create will be templates for the rest of the world, so the pressure to make them effective and interoperable is huge. There is a transatlantic memorandum of cooperation, and at present – despite a couple of exceptions yet to be resolved – harmonisation seems to be proceeding well. ICAO, as the touchstone for global standardisation, provides guidance on common standards and objectives.
And there are things each side can learn from the other. America, for example, is more advanced in the dissemination of real-time meteorological data among centres and to aircraft, and is ahead on the implementation of required navigation performance/GPS-based approaches and departures. Meanwhile Europe wants the USA to accept the ED-133 standard on flight trajectory data sharing that defines the interface between different civilian ATC Flight Data Processing Systems (FDPS), but this is still under discussion, according to Merlo.
Merlo says one of Europe’s objectives is to implement more performance-based navigation systems, as in America and many other countries. Some have been implemented in Europe, but based only on local initiatives, usually related to difficult terrain in the vicinity of specific airports, such as small airfields in Norway or the Faroe Islands. GPS-based required navigation performance (RNP) allows curved approaches, essential where close surrounding terrain is a problem, and is potentially advantageous in congested and complex terminal manoeuvring areas.
Merlo adds that the European Aviation Safety Agency is working on standards for European RNP, which will help things progress. RNP airfield approaches, perhaps linked into instrument landing systems (ILS) or augmented GPS runway approaches, have the potential to deliver more approaches and departure trajectories into a given piece of airspace, Merlo points out. This can improve capacity as well as safety, he observes, but where airports are surrounded by urban residential development, changes in approach and departure procedures are highly contentious. In crowded Europe, this is perhaps the principal reason for the region’s laggardly performance in the implementation of RNP, but the other factor is the ubiquity of traditional terminal navigation systems such as ILS. By contrast, the areas of the world where GPS-based RNP has been adopted fastest are those where no traditional precision navigation aids exist.
In December last year, the movers and shakers in SESAR, Eurocontrol and the EC met in Brussels at a “high-level meeting”. Its purpose was to review the progress of the European ATM Master Plan. According to Merlo, it was more of a reaffirmation than a reorganisation.
As well as cutting flight times, the SESAR project aims to reduce the cost of delivering ATM
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However, Merlo says there is much more going on than the application of technology. There is, he says, a growing determination that the business objectives of the exercise must be delivered. That means low cost and efficiency, not just clever systems. In fact, he says, the priorities for system deployment are now determined according to those that will deliver the best cost/benefit.
He acknowledges that the economic downturn since 2008 has given SESAR’s deployment programme a break. Before the recession, priorities were all about a scramble to develop the capacity to cope with rapidly increasing traffic. Since that increase did not happen, the priorities shifted in the direction of cost-efficiency and the need to support the struggling airlines. Now, Merlo says, gentle growth has returned, and a 1-2% traffic increase is expected this year.
The cost/benefit delivery plan has two dimensions, explains Merlo. The first dimension is the delivery of operational improvements that reduce distances flown between all departures and destinations, and therefore reduce fuel burn. The second involves reducing the cost of delivering ATM, which means making the ANSPs more efficient on a network-wide and an individual basis.
Merlo reckons there is a 6% gap between the operational efficiency of the existing system and that of an ideal route network. In realistic terms, he says, about half of that – a 3% improvement – is achievable, but even that 3% could deliver a €1 billion fuel-saving to the airlines annually. As for bringing down the ANSPs’ costs, that could deliver another €200 million in reduced user fees, he says, and one of the keys to this is centralising certain services rather than having all ANSPs performing all ATM and aeronautical information delivery functions themselves.
Merlo accepts that attempts to close area control centres so as to operate with fewer of them has – so far – always failed because national authorities want to keep high-level ATM skills within their borders. He hints, however, that centralising essential total network functions at specialist locations, rather than continuing with the traditional geographically based airspace management system, may be the way to go. However, this requires a mindset change, and there is no sign of that yet, he reckons.
Although Merlo says nobody disputes the benefit of centralising services, it is politically difficult for national governments to deliver such an objective. And to add to the difficulty of delivering centralisation, European rules on competition prevent the allocation of functions on a politically or geographically expedient basis, requiring competitive tendering by would-be providers.
A major obstacle to progress is the technological and investment challenge involved in the ultimate objective of implementing free route airspace enabled by accurate 4D trajectory management for every flight.
The principle of 4D management is that, throughout a route trajectory, every aircraft in the sky has a target time over (TTO) area navigation waypoints en route and at destination. At those waypoints, position and height are specified.
All these individual 4D trajectories are co-ordinated, thus achieving traffic flow management and separation. Merlo points out that the early stages are being trialled now, but he admits that a fully implemented 4D system is technologically hugely challenging and involves considerable investment in system-wide advanced datalinking capability, both on the ground and in aircraft. All the components have been validated in individual flight trials in real working airspace, but the complete systems interoperability and flightplan datalinking between ANSPs that is essential for this ambitious objective does not yet exist, says Merlo.
The result is that 4D will take five years longer to achieve than expected. This fact is now accepted and built into the SES plan, but it will affect the achievement of cost-benefit targets, Merlo admits. It will, however, definitely be achieved in the end, he insists.
In the meantime, he observes, simpler versions of partial 4D trajectory management, such as extended arrival management, are being implemented. An example is the partnership between the UK and French ANSPs to apply speed controls to aircraft well upstream when they are inbound for major hubs such as London Heathrow and Paris Charles de Gaulle. The result is the arriving aircraft can slot straight into an approach, instead of having to be put into a holding pattern – what Merlo calls “rush to wait”. And there are some European areas – such as Scandinavia – where good interoperability and advanced systems exist, so in Scandinavian airspace free routeing will begin this October, Merlo reveals.
Essential to a free-routeing environment is a conflict-alert system to help air traffic control officers (ATCOs) manage a dynamic 4D environment. But since – in theory – the network knows the predicted trajectories of all the aircraft, medium-term conflict alerts can be reliably generated by the system. If trajectory change is required, ATCOs can use a “what if” function to test a new tactical instruction before passing it to the aircraft crew. All aspects of the system performance of these functions is being trialled widely: in Southampton, UK; the Maastricht Upper Area Centre, Netherlands; Toulouse, France; Rome, Italy; and Langen, Germany. And of course the final separation safety net – upgraded versions of the traffic alert and collision avoidance system – is installed in all aircraft that operate within controlled airspace.
The roll-out of SESAR solutions for validation – all those objectives covered in this article – has reached what the planners call “Release 5”. To de-clutter the scene for those who cannot recognise progress while peering through the forest of multiple parallel SESAR programmes involved, the roll-out of Release 5 means that Releases 1 to 4 have been implemented. So SESAR is indeed advancing, just not in a spectacular manner.
Source: FlightGlobal.com
