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Guidance concerning Air Navigation in and above the NAT MNPSA




When using HF communications and even when using ADS and/or CPDLC, pilots should

maintain a listening watch on the assigned frequency, unless SELCAL is fitted, in which case they should

ensure the following sequence of actions:

  • a)

    provide the SELCAL code in the flight plan; (any subsequent change of aircraft for a flight will require passing the new SELCAL information to the OAC);

  • b)

    check the operation of the SELCAL equipment, at or prior to entry into Oceanic airspace, with the appropriate aeradio station. (This SELCAL check must be completed prior to commencing SELCAL watch); and

  • c)

    maintain thereafter a SELCAL watch.


It is important to note that it is equally essential to comply with the foregoing SELCAL

provisions even if SATCOM Voice or ADS/CPDLC are being used for routine air/ground ATS

communications. This will ensure that ATC has a timely means of contacting the aircraft.


Flight management staffs and crews of aircraft equipped with 12-tone SELCAL equipment

should be made aware that SELCAL code assignment is predicated on the usual geographical area of operation of that aircraft. If the aircraft is later flown in geographical areas other than as originally specified by the aircraft operator, the aircraft may encounter a duplicate SELCAL code situation. Whenever an aircraft is to be flown routinely beyond the area of normal operations or is changed to a new geographic operating area, the aircraft operator should contact the SELCAL Registrar and request a SELCAL code

appropriate for use in the new area.


When acquiring a previously owned aircraft equipped with SELCAL, many aircraft

operators mistakenly assume that the SELCAL code automatically transfers to the purchaser or lessee. This is not true. As soon as practical, it is the responsibility of the purchaser or lessee to obtain a SELCAL code from the Registrar, or, if allocated a block of codes for a fleet of aircraft, to assign a new code from within the block of allocated codes. In the latter instance, if 12-tone equipment is involved, the Registrar should be consulted when there is any question as to the likely geographical area of operation and the possibility of

code duplication.


The registrar can be contacted via the AFTN address KDCAXAAG, and by including

“ATTN. OPS DEPT. (forward to SELCAL Registrar)” as the first line of message text.

VHF Voice Communications


Aeradio stations are also responsible for the operation of General Purpose VHF (GP/VHF)

outlets. North Atlantic flights may use these facilities for all regular and emergency communications with relevant OACs. Such facilities are especially valuable in the vicinity of Iceland, Faroes and Greenland since VHF is not as susceptible to sunspot activity as HF. Outlets are situated at Prins Christian Sund, which is remotely controlled from Gander Aeradio station, and at Qaqatoqaq, Kulusuk, several locations in Iceland and the Faroes, via Iceland Radio. Theoretical VHF coverage charts are shown at Attachment 5. When using GP/VHF frequencies in areas of fringe coverage however, care should be taken to maintain a SELCAL watch on HF thus ensuring that if VHF contact is lost the aeradio station is still able to contact the aircraft. It is important for the pilot to appreciate that when using GP/VHF, as with HF and SATCOM Voice, these communications are with an aeradio station and the pilot is not in direct contact with ATC. However Direct Controller/Pilot Communications (DCPC) can be arranged, if necessary, via patch-through on some GP/VHF


NAT Doc 007


Edition 2010

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