Air/Ground Communications

In very broad terms, the operations of the Gufunes Communications Centre can be divided into two main areas. Communications with aircraft in flight (Aeronautical Mobile Service [AMS]) and operation of an AFTN/CIDIN message switch (Aeronautical Fixed Service [AFS]). The AFTN/CIDIN switch forms part of the international aviation-related message distribution system. The switch in Gufunes is connected to comparable switches in London, Norway, Canada and Greenland. In Iceland it is connected to the Area Control Centre, Keflavik Airport and various aircraft operators‘ facilities. Operational management of the system is in the hands of a watch officer in Gufunes with technical support provided by the Air Navigation Division.

Compared to the air/ground operation, that part of the Communication Centre which handles to air/ground communications is much more extensive and requires more manpower, oceanic procedures being predicated on the delegation of communications to specialized radio operators. The radio operator thus acts as an intermediary between the controller and air crew. The information exchanged includes:

  • Position reports at cleared reporting points
  • Pilot requests for changes in altitude, speed or route Air traffic control clearances from the area control centre
  • Weather information to and from pilots
  • Information provided to Airline OperationsCentres (AOCs)

The Communications Centre in Gufunes provides services 24 hours a day on HF and VHF GP frequencies. The Centre has a total of eight working positions to handle air/ground comm-unications.

The HF service is provided on three frequency groups:

Frequency group B
kHz
Frequency group C
kHz
Frequency group D
kHz
2899 2872 2971
5616 5649 4675
8864 8879 8891
13291 13306 11279
17946 17946 17946

Generally pilots prefer to communicate on VHF frequencies rather than on HF frequencies. The reason being that listening conditions are much better on VHF connections. However, the range of VHF connections is only a fraction of what is offered by HF connections. The range of VHF connections is limited to a little more than line of sight. It is therefore important to position the equipment as high up as possible to increase range. It is common for VHF connections to have a range of approximately 250 nautical miles. The geographical position of Iceland provides a certain uniqueness because by installing VHF equipment in Iceland, in the Faroe Islands and in Greenland, the Communications Centre in Gufunes can offer a continuous VHF service area over the North Atlantic. VHF GP service is provided on three frequencies: 126.55 MHz, 127.85 MHz and 129.75 MHz. In Iceland, VHF equipment is located on Gagnheiði, Háfell, Háöxl, Þorbjörn and Þverfjall. In the Faroe Islands, equipment is located on Fugley, and in Greenland, there is equipment in the Dye One and Dye Four stations. HF transmitter equipment is located in Grindavík and at Bessastaðir in West Húnaþing, and receivers are located in Þverholt in Borgarfjörður, at Garðskagaviti, and on the west coast of Norway. Furthermore, there is one transmitter and receiver in Söndreström on the west coast of Greenland. Each year, approximately 500.000 messages from the Centre are dispatched, and of those messages, 65% are on VHF frequencies.

Another part of the operations of the Gufunes Communications Centre is data communications with airplanes. In collaboration with the American communications company ARINC, equipment for data communications with airplanes on both HF and VHF frequencies is operated from Gufunes. In Grindavík, there are HF transmitters for this use and a receiver is located in Þverholt. Equipment for data communications on VHF frequencies is located on Háfell and Þorbjörn in Iceland, on Spáafell in the Faroe Islands, and in three places in Greenland, DYE One, DYE Four, and TOP775. With these locations, a zone with a continuous service area is provided over the North Atlantic on VHF frequencies, but outside that area, HF services are provided. Data communications with airplanes are continually increasing, both where airlines are receiving information from their own airplanes, and also, communications between airplanes and area control centres are increasingly moving over to data communications.

It is clear that the extent of radiotelephony communications with airplanes will decrease in the coming years. Today, these services are provided from six stations located in Ireland, Canada, the United States, Portugal, and Norway, in addition to Iceland. It is certain that these stations will decrease in number in the coming years. Approximately 50% of the traffic which travels through the Reykjavik control area today uses data communications. However, the increase in traffic which uses data communications will in part be offset by the overall increase in air traffic which is forecast for the coming years. Within Isavia, preparation has been underway for this change in operations structure. The stations in Gufunes and in Ballygirreen in Ireland have an agreement on interoperation. The Ballygirreen Radio Station provides communications services in the British/Irish control area (Shanwick) which lies south of the Reykjavik control area. The idea behind the collaboration is that instead of dividing the traffic between the stations according to the edges of the control areas, the traffic is divided so that traffic peaks at each station are minimised, that is, the work load is evenly distributed between them. In this way, the services can be improved and future expenditure lowered. At the same time, the stations serve as alternative stations for each other which lowers start-up costs and operating costs because a new alternative station will not have to be built.

Approximately 40 flight information officers, divided into 5 shift teams, work in the Communications Centre.

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