I am reading about NATs (North Atlantic Tracks) and I found out they are created and regulated by the following entities:

  • westbound flow: Shanwick Oceanic Control
  • eastbound flow: Gander Oceanic Control Centre

Since I cannot find their information but from other sources (non official!), my questions are:

  • What are their websites?
  • Where can I download the NATs information they generate?

Note: the information should be official and possible machine-readable.


Short and direct answer

ATC centers have no public websites in general. Aeronautical and ATC information is distributed by a fixed dedicated network, the aeronautical fixed service (AFS) and its data network AFTN.

From NAT Doc 007:

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.

FAA and other agencies provide for convenience the NATS message on the web, e.g. for FAA at:

You'll find this message repeated on many aviation blogs, embedded in a web page and served as text/html MIME type. Unfortunately I don't know whether a server provides it as text/plain.

However it's easy to extract tracks data using a syntactic parser. Many, if not all, routing/planner software use the URL above as the source of their NATS data. For example QSimPlanner, written in C# uses class NatsDownloader to download and parse NATS data from FAA site, using Linq parser: XDocument.Parse(wc.DownloadString(natsWest))

This is the direct answer to your question, but I'll provide additional details more related to what is track system and how the track messages are built twice a day. Feel free to continue reading!

Polar jet, organized track system and track messages

The north Atlantic track system (NATS) or north Atlantic organized track system (NAT-OTS) is a set of westbound and eastbound routes crossing the Atlantic ocean between North America and Europe.

Polar jet stream

Aircraft fuel consumption and ground speed can be significantly improved by using tailwinds or minimizing headwinds rather than just following the shortest path (great circle) between two locations.

The prevalent winds in altitude in this area are due to the interaction between the Ferrel cell and the polar cell (this theory is still a discussion). They are seemingly deflected eastward by the rotation of the Earth (Coriolis fictitious force). The position of the cells slowly changes and winds with them.

enter image description here
Atmospheric circulation (source)

This interaction and the lower tropopause near the poles result in the polar jet undulating from Canada to northern Europe at an altitude of about 8-10 km. Speed is often between 50 and 150 kt, but 200 kt has been seen.

On this map the colored lines are locations of equal wind speed, aka isotachs. The maximum intensity depicted in red is the polar jet:

enter image description here
Polar jet (source)

The thickness of the polar jet streams is usually less than 5 km and their width a few hundreds of km. To take advantage of jet streams when flying to Europe, aircraft must be packed into this area.

Conversely aircraft flying to the US need to follow routes where the winds, that are now headwinds, are the weakest.

North Atlantic track system

The track system is aimed to propose a set of routes in both directions, aligned with the jet streams, with waypoints selected to ensure proper separation. ICAO guidance for planning and using this airspace between FL285 and FL420, where almost all commercial traffic occurs, is described in NAT Doc 007.

Due to the absence of radar stations, crossing the ocean is currently done without radar surveillance and coordinated by five oceanic area control centers (OAC): Gander, Shanwick, Reykjavik, Santa-Maria and New York East. Aircraft report their positions to the OAC, and OAC ensure a safe separation.

The tracks use a set of fixed entry and exist points at their extremities:

Overall NAT-OTS structure
Overall structure, with entry and exist points (source)

Those points change over time when the NAT airspace is reorganized, e.g. with the adoption of HLA in replacement of MNPS.

Due to the distribution of winds in the polar jet, flying from Europe to North America is done more northerly than flying from NA to Europe.

Day-time (westbound) NAT-OTS Day-time (westbound) tracks A, B, C, ... (source)

Night-time (eastbound) NAT-OTS
Night-time (eastbound) tracks Z, Y, X, ... (source)

We can compare the tracks and the winds, e.g. westbound tracks:

NAT-OTS versus winds
Easterly winds and westbound tracks (source). Wind symbol explanation.

The westbound tracks A, B, C... clearly try to avoid headwinds rather than following the yellow great circle located more northerly.

(Concorde, flying at a higher altitude, where winds are different, had specific tracks).

The only radar information available for ocean crossing is at the border of oceanic centers and the neighboring domestic centers. These domestic ATC have a delegation for controlling terminal sections of the tracks, e.g. on the European side:

Shanwick OCA and domestic ATC
Targeting Risk Within The Shanwick OCA (Youtube)

Track system construction

The process is collaborative between airlines and ATC.

From Wikipedia:

The day prior to the tracks being published, airlines that fly the North Atlantic regularly send a preferred route message (PRM) to Gander and Shanwick. This allows the ATC agency to know what the route preferences are of the bulk of the North Atlantic traffic

From SKYbrary:

The night-time OTS (eastbound) is produced by Gander OAC and the daytime OTS (westbound) by Shanwick OAC, each incorporating any requirement for tracks within the New York, Reykjavik, Bodø and Santa Maria Oceanic Control Areas (OCAs). The OTS planners co-ordinate with adjacent OACs and with domestic ATC agencies to ensure that the proposed system is viable. They also take into account the requirements of opposite direction traffic and ensure that sufficient track/flight level profiles are provided to satisfy anticipated traffic demand.


Following the initial construction of the NAT tracks by the appropriate OCA, the proposed tracks are published on an NAV Canada operated internet site for review and discussion by interested parties. One hour is allocated for this process during which any comments will be considered by the publishing agency and any agreed changes are then incorporated into the final track design.

Track messages

Data regarding NAT-OTS are exchanged between involved parties on aeronautical fixed telecommunication network (AFTN), a data service of the ATS. At the beginning the exchange was possible using teletypes (telex), the limited capabilities of the system dictated the abbreviated form of aeronautical messages, which continued when the system was modernized.

The track messages look like this:

A SUNOT 57/20 58/30 58/40 58/50 CUDDY
WEST LVLS 310 320 330 340 350 360 370 380 390
B PIKIL 56/20 57/30 57/40 57/50 HOIST
WEST LVLS 310 320 330 340 350 360 370 380 390
C RESNO 55/20 56/30 56/40 56/50 JANJO
WEST LVLS 310 320 330 340 350 360 370 380 390

This one describes three tracks A, B, C. For instance track A, which is the most northerly of the westbound tracks:

A SUNOT 57/20 58/30 58/40 58/50 CUDDY
EAST LVLS NIL WEST LVLS 310 320 330 340 350 360 370 380 390

is a track starting at SUNOT and ending at CUDDY, with intermediate waypoints at 20°, 30°, 40° and 50° longitude W. Respective latitudes are 57°, 58°, 58°, 58° (see map above for waypoints).

The significant point are at a distance of 10° longitude for flights operating at or south of 70°N, 20° in other cases.

This track has no available FL for eastbound flights. Westbound flights can use FL310 to 390. This is a US bound track against wind.

Eastbound tracks are named starting at Z for the most southerly track.

OTS Changeover Period

From SKYbrary:

To provide a smooth transition between the night-time and the daytime OTS, a period of several hours is allocated between the termination of one system and the commencement of the next. These periods are from 0801 to 1129 UTC and from 1901 to 0059 UTC.

During the changeover periods, some restrictions to flight planned routes and levels are imposed and opposite direction traffic must remain clear of the inbound (terminating) OTS.

Suggested (good) reading

  • 1
    $\begingroup$ This is a very good answer! Thanks!!!! $\endgroup$ – Federico Gentile Nov 4 '16 at 7:46
  • $\begingroup$ How often are the NOTAM updated during the day? Is it randomly or do they follow a specific schedule? $\endgroup$ – Federico Gentile Jan 11 '17 at 10:16
  • $\begingroup$ I mean, the faa link you gave me updates the NOTAM every few minutes (sometimes 10 min, 15min ...) but the content is always the same... how is it possible? Is there a logic behind that? $\endgroup$ – Federico Gentile Jan 11 '17 at 16:39

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.