ATM Modernization, Business & GA, Commercial, Military

Q&A: Col. Jan Plevka: Military/Civil Interoperability in European Airspace

By George Marsh | August 1, 2005
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Under Europe's vision of a "single sky" and more flexible airspace, military and civil aircraft will share airspace on a more equal footing than ever before. However, this equality means more and more military aircraft will have to be equipped to civilian communication, navigation, surveillance/air traffic management (CNS/ATM) standards. Eventually, almost all aircraft using core European airspace will need to be equipped to accommodate the Single European Sky concept.

To learn about Europe's plans for civil-military interoperability in its airspace, Avionics Magazine interviewed Col. Jan Plevka, former chairman of the CNS Focus Group at Eurocontrol in Brussels. Plevka served as a military expert at the agency's military unit. As such, he was involved in many European ATM (EATM) programs, including communication strategy development, the global navigation satellite system (GNSS) program steering group, the navigation infrastructure group, the Link 2000+ program steering group, the Central European Air Traffic Services (CEATS) regional EATM implementation group, and the overall CNS/ATM architecture. Plevka was chairman of the Eurocontrol military team CNS focus group.

In his home country Plevka was responsible for military CNS/ATM systems in the Czech Air Force and was a program manager in charge of transforming the Czech Air Force to International Civil Aviation Organization (ICAO) standards. Our interview with the Air Force colonel and Ph.D. graduate took place in Brussels.

Avionics: What is the Civil-Military CNS/ATM Systems Interoperability Roadmap?

Plevka: It's a guideline plan to achieve interoperability between future civil and military CNS/ATM infrastructures so that state aircraft, flying as general air traffic can share European airspace with commercial aircraft. Among other issues, the roadmap will point out the need for harmonized transparent qualification/certification and transition arrangements.

Avionics: Define state aircraft.

Plevka: Mainly military, but also aircraft operated by police, customs and other official bodies for public, non-commercial purposes. They could range from a light police observation aircraft to a head-of-state jumbo jet. Estimates suggest that across the ECAC [European Civil Aviation Conference] area, the ATM system has to accommodate over 4,600 combat aircraft, almost as many helicopters, nearly 1,400 large aircraft--transport, cargo, tanker and maritime patrol--and about 400 paramilitary aircraft.

Avionics: How does Eurocontrol define interoperability?

Plevka: Bringing civil and military CNS/ATM systems into convergence, such that state aircraft and civil aircraft can have access to the same common airspace on equal terms--except that sometimes military traffic requires priority, for example, for air defense intercept flights and humanitarian relief missions that are time-critical. Requirements under the plan should be in harmony with those of ICAO and the U.S. Global ATM [GATM] concept.

Avionics: Why is interoperability so important?

Plevka: There are two main issues: One is that airspace over Europe is a finite resource, and the large growth in air traffic is driving a need to use it more intensively. This is pushing us towards a more flexible use of airspace.

The second issue is that new navigation concepts are being developed to satisfy the demands of operational capacity and the environment. Air traffic management in Europe now requires solutions like reduced vertical separation minimum [RSVM] and required navigation performance/area navigation [RNP/RNAV]. Delivering these safely requires an extremely high level of CNS/ATM interoperability. Although state aircraft can at present be exempted from some of the requirements, this should be seen as part of a transition phase, as migration towards interoperability takes place.

Allowing all aircraft unrestricted and equal access to this new dynamic and flexible airspace environment requires a large measure of agreement over its future use and a high level of system interoperability. Delivering this is integral to Eurocontrol's flexible use of airspace concept, under which all airspace should be considered as one continuum and used flexibly on a day-to-day basis. Stating a required performance will, we feel, be more acceptable to all parties than trying to prescribe what equipment will be used.

Avionics: Could you say more about convergence?

Plevka: Air traffic management has to support national security and day-to-day military operations, as well as civil aviation. Strong civil military cooperation is therefore a must. This is best facilitated where a high level of interoperability between civil CNS/ATM and military GATM infrastructures is achieved.

Moreover, major increases in air traffic over Europe require more rational air traffic management than can be achieved with the largely separate civil and military ATC infrastructures that we have today. We've had too much divergence over the years, and that's not the way forward. If the intended Single European Sky is to be shared, with equal rights for both state and commercial operators--[with the understanding] that military and security operations must sometimes have priority--the infrastructures will have to converge. Fortunately, new technologies are already moving that way, and we have the opportunity to make it happen. The Eurocontrol roadmap should concentrate the minds of stakeholders and help them make the most of that opportunity.

Avionics: Will civil aircraft have access to what is now military airspace?

Plevka: That depends on what is decided at the national level. We at Eurocontrol believe in promoting flexibility to the maximum extent possible consistent with safe sharing. Although that is what we will recommend, it is up to individual governments to decide to what extent our guidelines should be implemented within their jurisdictions.

Clearly, there will always be a need for some airspace to be set aside for high-maneuver operations that could be dangerous for other aircraft in the vicinity--air combat training, for example--and published as such. But there should be fewer of these temporary segregated areas [TSAs] and more use of temporary restricted areas for the many flight operations that are more predictable and manageable. Civil aircraft can then be routed over or around these at the times concerned.

Avionics: What's the roadmap time scale?

Plevka: Work began last summer in bringing Eurocontrol's various CNS domains together to focus on interoperability issues. In September the military team agreed to the formation of a CNS focus group. The following month, work started in earnest on developing the roadmap. Various interests have been brought into the process; for example, we have had liaison meetings with representatives from NATO and other stakeholders.

At a meeting scheduled for early June, we expect to distribute a provisional roadmap document to all members of the military team for their review and comment. Representatives from relevant agencies will also receive copies. A couple of months will be allowed for feedback, and then there will be further work on issues arising. Next, the initial text will be amended. Our target for issuing the definitive roadmap is the end of this year.

That draft is unlikely to be final. We see the roadmap as a living document, evolving in the light of technological and institutional developments. For example, if Europe's present CASCADE [Cooperative ATS through Surveillance and Communication] project recommends particular applications using new data link technologies, that would be reflected in a roadmap update.

Avionics: To what extent will state aircraft have to be equipped to comply with future interoperability requirements?

Plevka: Today state aircraft that are not fully equipped to current CNS/ATM standards are generally accepted into the system on an approved exemption basis--although there are occasions when service has been refused. But that is not, we think, a way we can continue into the future. A more crowded and dynamic airspace environment will be less amenable to a significant number of exemptions. True interoperability will be needed to ensure both safety and better efficiency.

For a while non-equipped aircraft will still be accommodated. But as the skies become busier and routes freer, increasing harmonization of civil and military ground ATC infrastructures will become more essential. To be fully accepted into this environment, airspace users--whether commercial or state--will have to be equipped to common CNS capability standards.

A few exceptions will still apply, for example, a one-off or very occasional flight from an African or Asian country, let's say, will still be handled. But "frequent flyers"--by which we mean those who fly more than 30 hours per year in core European airspace--will have to meet the interoperability requirements if they are not to be refused service and asked to reroute. There will be more monitoring tools available in the future to record evidence about such users.

Avionics: What does the roadmap mean for the ground infrastructure?

Plevka: A major task will be to harmonize communications practice and technology. This probably will mean moving towards a TCP/IP [transmission control protocol/Internet protocol] network-based system for relaying flight and surveillance data between centers. We expect to see a transition from the present AFTN [aeronautical fixed telecommunications network] and CIDIN [common ICAO data interchange network] infrastructures to the more flexible AMHS [aeronautical message handling system] for ground-to-ground communication. Common data formats will have to be adopted.

For communications between air and ground, ATC centers will need 8.33- KHz-capable VHF radio facilities, but will also have to retain UHF capability for those military aircraft that do not become VHF-equipped.

Control centers in Europe are already being upgraded for the improved secondary surveillance radar [SSR], with its associated Mode S elementary and enhanced data link now being adopted here. But they also will have to accommodate legacy SSR-equipped aircraft. Implementation of multilateration, a novel surveillance system not requiring additional aircraft equipment, is increasing. In the longer term, we expect a transition away from cooperative or noncooperative surveillance towards cooperative separation assurance [CSA]. This will require new technology based on data sharing.

Avionics: How will the roadmap impact onboard avionics?

Plevka: Operators of state aircraft requiring unrestricted access to core European airspace will have to consider forward fit or retrofit of some or all of the following CNS equipment.

  • VHF--aircraft will need 8.33-KHz-capable VHF radios, which, for military aircraft, will be additional to military-standard UHF communications. Operation outside non-8.33-KHz areas, such as below FL245--at present--will require standard 25-KHz voice VHF radios.

  • Data link--state aircraft wishing to operate in core airspace where controller pilot data link communication [CPDLC] is in operation will need to fit ATN/VDL-2 [aeronautical telecommunications network/VHF digital link, Mode 2] data-capable radios, an upgrade that is provided for in Europe's Link 2000+ program. This air-ground data link will be a key starting point in supporting the future automation of ATM. VDL-2 is the only fully defined and developed CPDLC-capable data link available at present, though CASCADE might propose others for the future.

  • Surveillance data link--provision will be required for Mode S elementary and enhanced surveillance data communication. Future requirements might also include ADS-B [automatic dependent surveillance-broadcast].

  • ACAS [airborne collision avoidance system] and EGPWS [enhanced ground proximity warning system] are mandatory.

  • ILS/FM immunity--ILS/VOR receivers are needed that meet European signal immunity standards, so that they are not subject to interference from FM broadcast stations.

  • Navigation to required navigation performance standards--navigational equipment will be needed to meet increasingly precise RNP criteria. Typically, in the future this could be some form of GNSS and inertial navigation system [INS] combination, supported by terrestrial systems--DME/TACAN, for example. GNSS systems will ideally be multimodal, able to process signals from GPS/GPS-2/Galileo and the European geostationary navigation overlay system [EGNOS]. Four-dimensional area navigation [4D-RNav] is under consideration to meet all requirements gate-to-gate by 2015.

  • Altitude measurement, control and alert systems having the accuracy and integrity to support reduced vertical separation minimum are needed.

Mandatory dates for fitting these various systems extend from this year through to the next decade, and many state aircraft have much of what is required already. Thus, achieving full interoperability compliance may not be as daunting as might appear at first sight. The roadmap will take full account of economic constraints, lengthy procurement cycles and cockpit integration issues.

Avionics: How have the stakeholders responded to the roadmap?

Plevka: Naturally, many outside Europe have trouble comprehending the sheer intensity of air traffic operations here and are suspicious of concepts like civil/military interoperability and Global ATM because of the costs involved. However, most of the potential stakeholders we've spoken to welcome the roadmap initiative. Military forces think it will be useful as a baseline for future activities and say it's the first time interoperability has been addressed in bringing all the domain strategies together.

Other state aircraft operators and ATC service providers like the thought of having a document that can help guide their planning and investment decisions; it makes the situation a little less fluid and more predictable. Reservations about costs and time-scales are, of course, understandable, but it will be up to individual operators to decide whether, for them, the costs [of equipping] outweigh the benefits. Some military operators are gearing up for interoperability already--the United States forces for example. [Feb. 2005, page 26].

Avionics: How will UAV operations complicate the issue?

Plevka: It's not yet a current subject for the CNS focus group, since a separate task force on ATM requirements is considering the whole question of such operations for UAVs. Generally, Eurocontrol envisages that UAVs will be able to operate in designated airspace on equal terms to manned aircraft and that air traffic control will treat them in a similar way.

Avionics: When should full compliance with interoperability requirements be achieved?

Plevka: Probably not before the second half of the next decade, maybe by 2020. Timelines and systems availability are different from one system to another. For example, EGNOS is coming on stream this year, but Galileo will not be ready before about 2008. In communications, the full potential of CPDLC to achieve cooperative ATM will not be realized for several years, and the likely future air-ground communication systems are not foreseen before 2015.

Also, it's a difficult transition to manage. In contrast to the civil sector, where airlines are not generally involved directly in ATM provision, air forces are typically their own ATM providers. But procurement agencies are outside that loop. Coordinating these various interests is therefore a significant challenge.

Avionics: Have you carried out any cost-benefit analyses?

Plevka: This is an ongoing task. There's a difficulty though. In contrast to commercial operators, who can balance revenues against costs very precisely, it is hard for a military organization to carry out a meaningful analysis. How, for instance, do you put a value on a mission successfully completed? That is not to say we shouldn't try. A precedent was set by [cost benefit analyses] carried out for state aircraft within the 8.33-KHz and Mode S programs.

Avionics: Who are your sources for advice and viewpoints?

Plevka: We have substantial resources internally. Eurocontrol has, in addition to a military unit and a number of military experts, a standard, established working structure encompassing task forces and focus groups, as well as a civil/military interface standing committee and other military ATM forums.

Externally, Eurocontrol has good cooperation with NATO--there's a memorandum of cooperation between the two organizations--and NATO representatives have been at our meetings. There is also a line of communication with ICAO since Eurocontrol participates in ICAO groups. Our plans are generally in line with ICAO's ATM/CNS Global Plan. We are liaising with the EU [European Union] and the FAA. Of course, we are in touch with national air traffic service providers and military authorities.

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