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Guidance concerning Air Navigation in and above the NAT MNPSA


provided to serviceability

satisfy anticipated traffic of transition area radars and


The impact on domestic route structures

navaids are checked before the system is finalised.




When the expected volume of traffic justifies it, tracks may be established to accommodate

the EUR/CAR traffic axis or traffic between the Iberian Peninsular and North America. Extra care is required when planning these routes as they differ slightly from the 'core tracks' in that they may cross each other (using vertical separations via different flight level allocations), and in some cases may not extend from coast-out to coast-in (necessitating random routing to join or leave). Similarly, some westbound tracks may commence at 30°W, North of 61°N, to accommodate NAT traffic routing via the Reykjavik OCA and

Northern Canada.

Collaborative Decision Making Process


Operators proposing to execute NAT crossings during the upcoming OTS period are

encouraged to contribute to the OTS planning process. A comprehensive set of Collaborative Decision

Making (CDM) procedures for NAT track design is now employed.


This CDM process commences with the Preferred Route Message (PRM) system, which has

been used in the NAT Region for many years. To enable oceanic planners to take into consideration operators' preferred routes in the construction of the OTS, all NAT operators (both scheduled and non- scheduled) are urged to provide information by AFTN message to the appropriate OACs regarding the optimum tracks of any/all of their flights which are intended to operate during the upcoming peak traffic periods. Such information should be provided, in the correct format, as far in advance as possible, but not later than 1900 UTC for the following day-time OTS and 1000 UTC for the following night-time OTS.

Addresses and formats for providing PRMs are published in the Canadian and UK AIPs/NOTAMs.


Subsequently, following the initial construction of the NAT tracks by the publishing

agencies (Gander OAC for Eastbound tracks and Shanwick OAC for Westbound tracks), the proposed tracks are published on an internet site for interested parties to view and discuss. One hour is allocated for each of the proposals during which any comments will be considered by the publishing agency and any changes which are agreed are then incorporated into the final track design. This internet site is currently operated by NAV CANADA. Access to this site is by password which any bona fide NAT operator may obtain on

application to NAV CANADA - see Canada AIP for details.




The agreed OTS is promulgated by means of the NAT Track Message via the AFTN to all

interested addressees. A typical time of publication of the day-time OTS is 2200 UTC and of the night-time

OTS is 1400 UTC.


This message gives full details of the co-ordinates of the organised tracks as well as the

flight levels that are expected to be in use on each track. In most cases there are also details of domestic entry and exit routings associated with individual tracks (e.g. ‘NERS…’ or ‘NAR …..’). In the westbound (day-time) system the track most northerly, at its point of origin, is designated Track 'A' (Alpha) and the next most northerly track is designated Track 'B' (Bravo) etc. In the eastbound (night-time) system the most southerly track, at its point of origin, is designated Track 'Z' (Zulu) and the next most southerly track is

designated Track 'Y' (Yankee), etc..

Examples of both eastbound and westbound systems and Track

Messages are shown below in this Chapter.


The originating OAC identifies each NAT Track Message, within the Remarks section

appended to the end of the NAT Track message, by means of a 3-digit Track Message Identification (TMI) number equivalent to the Julian calendar date on which that OTS is effective. For example, the OTS

NAT Doc 007


Edition 2010

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