Well worth PBN in 2019

Rotary radio beacons are of little importance for aviation

For about 10 years, a large number of wind energy projects have failed because permit applications are rejected on the grounds that an air traffic control facility could be disrupted (Section 18a I LuftVG). In 2019, the number of wind turbines affected was over 1,100 [1]. This corresponds to a cumulative output of around 4.7 GW. As a rule, it is about air traffic control systems of the variants VOR and DVOR - so-called rotary radio beacons.

I. What role do rotary radio beacons play in aviation?

Rotary radio beacons have been an established part of flight navigation since the 1950s at the latest. Nevertheless, the importance of conventional navigation systems is declining more and more in the context of the global changeover of instrument flight procedures to so-called performance-based area navigation (PBN). PBN essentially requires that an aircraft be capable of area navigation, i. H. has an on-board navigation computer (RNAV / RNP system) [2]. The RNAV or RNP system and its navigational accuracy, which i.a. is made possible by the navigation infrastructure in the relevant airspace, must meet the requirements of the respective ICAO navigation specification. In the EU, according to EU regulation 2018/1048, all air navigation service providers and airport operators must convert their instrument flight procedures and the corresponding navigation infrastructure to area navigation with specific performance values ​​as defined by PBN by 6 July 2030 at the latest [3].

Each phase of an IFR flight is assigned specific navigation requirements for PBN, each of which can be met by a combination of navigation sensors. For an approach procedure, for example, RNAV 1 or RNP 1 must be met, both of which require a satellite navigation system and, in addition, DME and inertial navigation. Rotary radio beacons are only provided as an option for base area navigation (RNAV 5) [2]. Nevertheless, even after the PBN requirements have been implemented in accordance with Article 6 of EU Regulation 2018/1048, a conventional navigation infrastructure must be maintained as a fall-back level in order to ensure that air navigation service providers can also provide their services when GNSS or other methods used for performance-based navigation are not be available. However, the ordinance does not provide any information on the scope of the infrastructure required.

II. How many rotary radio beacons can be removed?

An estimate of the extent of the reduction in the VOR stock is contained in ICAO Annex 10, Vol. I in Appendix H [4]. The provision of RNAV 5 on the basis of VOR / DME is then subject to considerable restrictions, since integrated multi-sensor navigation is rarely based on the combination of VOR / DME and in some cases limits the area of ​​application to 25 NM. In addition, few aircraft would have an RNAV 5 system based solely on VOR / DME. The ICAO therefore advises against using VOR / DME to provide PBN services. The only exception could be support for RNAV 5 routes at or near the bottom of the routing where DME / DME coverage is inadequate. Rotary radio beacons should be dismantled in connection with the introduction of PBN in order to reduce costs [4]. In addition, no new VOR should be set up. The ICAO estimates that 50% or more of the existing rotary radio beacons can be dismantled. States should therefore develop a rationalization plan taking into account the age of the VOR, their respective use and operational importance.

The performance requirements for instrument flight do not stand in the way of an orderly dismantling of radio beacons [3]. One of the main challenges, however, is that not every aircraft has the equipment necessary for area navigation. In Europe in 2010 around 96% of aircraft were equipped with base area navigation equipment, 87% had GNSS [2]. A number of aircraft are therefore dependent on a conventional navigation infrastructure including rotary radio beacons. Another challenge is that the air traffic control organizations are not given any binding specifications for the dismantling of the VOR network. This is understandable with a view to flight safety, but makes planning the wind energy expansion more difficult, as it remains unclear when which radio beacons will be dismantled if necessary.

III. What is the dismantling plan in Germany like?

In this respect, DFS only makes vague statements. According to a press release dated September 22, 2017, the transition from conventional navigation infrastructure to area navigation as part of the DFS concept should be completed nationwide in several stages at all 60 German IFR airports by 2029 [5]. To do this, around 2,800 approach and departure procedures would have to be redesigned. An adaptation of the airspace structure is also necessary. The German airspace is divided into seven clusters, which contain airports that are in close proximity to one another and that have dependencies. The chronological order for the implementation of the clusters is based on air traffic control requirements such as upcoming process adjustments and the age-related renewal of conventional navigation systems (VOR). The start of the introduction of the innovative procedure for approach and departure, used for the first time in Germany, will take place after an extensive review process at the end of 2020 in northern Germany in the Elbe / Weser cluster. At this point in time, operational use of the Michaelsdorf rotary radio beacon in Schleswig-Holstein, which could then be dismantled, was also canceled. The construction of new ground-based air traffic control systems in the Elbe / Weser area is no longer necessary. The areas freed up would then be available for other uses. Rotary radio beacons would, however, remain indispensable at some locations in Germany. According to current planning, a total of eight older systems of the current 58 rotary radio beacons in Germany are available.

IV. Conclusion

Rotary beacons are an outdated technology that no longer plays a central role in aviation. Only aircraft without base area navigation equipment regularly use them for navigation - this only affects a small proportion of the entire aircraft fleet. Accordingly, the plans of the international civil aviation organization and EUROCONTROL provide for a significant dismantling of the terrestrial air traffic control infrastructure. Only a small stock is maintained as a fall-back level.




[1] Agency for Wind Energy on Land e. V., Obstacles to the expansion of wind energy in Germany. Results of an industry survey carried out in the 2nd quarter of 2019 in cooperation with the BWE (author: Jürgen Quentin), available at: https://www.fachagentur-windenergie.de/fileadmin/files/Veroeffnahmungen/Analysen/FA_Wind_Branchenumfrage_beklracht_WEA_Hemmnisse_DVOR_und_Militaer_07-2019.pdf

[2] Eurocontrol, European Airspace Concept Handbook for PBN Implementation, Ed. 3, available at: www.eurocontrol.int/publication/european-airspace-concept-handbook-pbn-implementation

[3] Behrend, Scientific background document on the influence of wind turbines on flight operations with VHF radio beacons on behalf of the Bundesverband WindEnergie e. V., available at: www.wind-energie.de/fileadmin/redaktion/dokumente/pressemitteilungen/2019/20190306_BWE_VOR_WEA_final_FB.pdf

[4] ICAO Annex 10, Vol. I (as of November 10, 2016), Annex H, 3.3.

[5] DFS, The German air traffic control starts navigation of the future, press release from 09/22/2017

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