27 Fevereiro 2013

(versão resumida Vic Barros – 25FEB13)

Não invalida a leitura recomendada sobre a matéria no site da IVAO em:

IVAO/Departments/Flight Operations/Reference Library/Flying the NATs




Crossing the Atlantic - A brief guide


With increasing cover of the Atlantic FIRs on IVAO, it has become apparent that there is still a lack of understanding on the pilots' side of the procedures and differences in between flying in domestic Airspace and Oceanic Airspace.


This guide is set out to simplify the present training material into an easy to understand and translate guide. It shall by no means substitute the present Procedures, but enhance and boil them down to the bare essentials.

On conclusion of this guide you, the pilot should be able to:


• File a correct flight plan for Oceanic Flights

• Obtain the Oceanic Clearance by Voice

• Make Position Reports as appropriate.




With the introduction of jets into commercial passenger operations the Oceans have become very busy with air traffic, which has become an increasing challenge for air traffic controllers to ensure that all aircraft reach their destinations.

Owing to the fact that there is still no radar device that is capable of covering the Atlantic Ocean with reliable radar cover, therefore controllers working on the oceanic sectors need to revert to simple principles of Time, Speed and Altitude in order to keep flights separated.


Apart from using these principles it was also decided that:


A. The majority of westbound flights are to be conducted during European Daytime.

B. Equally the majority of eastbound flights are to be conducted during European Nighttime.


Along with these two principal rules it was agreed by the International Civil Aviation Organisation (ICAO) to bundle the North Atlantic Traffic onto several tracks, called the Organised Track System (OTS).




Each day the Shanwick and Gander Control Centers release a set of 5 to 7 tracks in each direction. Typically they carry the letters A to G for the westbound tracks and U to Z for the eastbound tracks.

These Tracks consist of two RNAV Entrypoints followed by four or five coordinates of Latitude and Longitude and again of two RNAV exitpoints.


The tracks are being defined and published with due consideration to the Weather situation on the day, especially with consideration to the jet stream winds, which are westerly.


The westbound tracks are usually aimed to lay outside the core of the jetstream to eliminate unnecessary headwind, while the eastbound tracks are aimed into the core of the Jetstream to make use of the tailwind.


The validity of the westbound tracks goes from 11:30 Zulu time to 19:00 Zulu

The validity of the eastbound tracks goes from 01:00 Zulu time to 08:00 Zulu


If you fly in either direction outside the given times you will be having to fly a random route,

more on that later.





The Tracks and their routings are published in the so called Track Message. To check that the Track Message displayed is the up to date, the Track Message is coded with an identifier, also referred to as TMI, which orientates itself on the day of the year. The message issued on 1st January becomes 001 and so on. This Identifier must be quoted on the oceanic clearance read back if you fly a published North Atlantic Track.


You can view the day's tracks and the archive here

To view my example tracks, type in 002 at the top and press go.


I will explain the structure of the tracks using tracks D and U from the day's tracks:



MALOT                               54/20 55/30 56/40 55/50             OYSTR STEAM

Entry Point                         Coordinates                                      Exit points



COLOR RONPO                 47/50 50/40 53/30 54/20             DOGAL BEXET

Entry points                       Coordinates                                      Exit points


Along with the coordinates you can see on the pages which flightlevels are available on the respective tracks.

Note that there is also a mandatory onward routing for the westbound tracks and a preceding mandatory routing for eastbound tracks. This is referred to as the North America Route. These are airways (rotas) connecting the Oceanic Entry/Exit points to RNAV way points just south of the US Border.



The use of a North American Route to and from a track is mandatory.


In our examples these NARs are NIL (mas não devia…) for Track D and N43A and N49A for Track U.


To find out which of the NARs are the most efficient to use you should consult the Jeppesen table which Samy has provided here:





All of this information should help you choose the most appropriate track for your flight to use. To determine which Track is to be used ultimately, you should use the Great Circle Calculator here:


Or alternatively you can make use of the Route Generator to determine which is the most

appropriate track to use:


The North Atlantic Tracks are typically the most appropriate Means to cross the Atlantic if heading to or from the following destinations:


North-East Canada

US-East coast as far as Atlanta

Central USA usually as far as Chicago


However for most destinations west of Chicago and South of Atlanta the NATs become a considerable detour, for these destinations it is far more appropriate to use a random routing. This will be explained at the end of this Tutorial.





Now, we go to the Flightplan, which needs to be adapted accordingly to reflect flying through oceanic airspace.

All flights are filed on the premises of Mach speed inside the airspace which is indicated on the entry point by:


M0XX/F3XX, where the X is replaced by the appropriate figures.

And on the exit fix by N0XXXF3XX


To put it all together, I have illustrated a sample route and flight from London Heathrow using the above Track D. Please note that this route is only an example and due consideration must be taken to use the correct tracks on the day.

The correct and complete route including the speed changes:




Also there should be a note of the TMI in the Remark section.




The general setup of the aircraft is similar to normal operations, however there is a difference in the FMC setup for the Oceanic Part.


After MALOT is entered it is time to put in the Coordinates, this is done as follows.


In the Boeing Honeywell FMCs (737,747,757,767,777):


  1. Go to the LEGS page;


  1. Enter the coordinate in the following format:


53/20 becomes N53W020

53/30 becomes N53W030


In the Airbus and MD11 FMC the waypoint can either be entered directly on the Discontinuity on the FPLAN page or alternatively on the LAT Rev page of the last waypoint, i.e. MALOT in the following:


53/20 becomes 5320N

53/30 becomes 5330N


If Active Sky is used, it is a good idea to generate a .pln File to calculate the enroute winds using http:\\

Then the wind information should be entered on the Legs page in the Boeing FMC.



The Flight - IFR Clearance


The first key difference in our flight is that the IFR clearance will only be given untill the entry point, MALOT. The Oceanic Controller will then issue the onward clearance.

Therefore the IFR clearance phraseology looks thus:


Pilot: Heathrow Delivery, good day, Speedbird 179, Boeing 747, Stand 545 with information Echo, requesting IFR clearance.


ATC: Speedbird 179, Heathrow Delivery, good day, cleared to MALOT via Compton 3G departure, Squawk 1140


Pilot: Cleared to MALOT via Compton3G departure, Squawk 1140, Speedbird 179


ATC: Speedbird 179, Readback correct, report fully ready to Ground 121.9


After this, the preflight and departure continue just the same way they would do normally.



The Flight - Oceanic Clearance


After departure it is time to check the ETA at the Entry point, MALOT.

You need to call NO LATER THAN 30 minutes before the entry point to get your clearance. If you are inside an area controller's sector, do not worry. The Area Controller will be fully aware of you needing the clearance and will release you.


If you are located in Ireland, you need to contact Shanwick for the Clearance while still on the ground.


Pilot: Speedbird 179 request frequency change to Shanwick for Clearance.


ATC: Speedbird 179, that is approved, report back.


Pilot: Wilco, Speedbird 179.


Now, before you call Shanwick please make sure you have the following details ready at hand:


· Aircraft type

· Requested Track

· Requested Flightlevel

· Requested Speed in Mach

· Estimate of the Entrypoint

· Maximum flightlevel possible in case level of choice is unavailable


Then check no one else is receiving/ reading back or requesting a clearance, then it’s your go.


Pilot: Shanwick, good day, Speedbird 179.


ATC: Speedbird 179, Shanwick, standby


IMPORTANT NOTE: If the controller of either Delivery or Radio say Standby:

The Controller will call you when he is ready to take your details, you need to wait for him to be ready.




When the controller is ready he will come back to you and say:


ATC: Speedbird 179, pass your message.


Pilot: Speedbird 179, Boeing 747, inbound MALOT, Estimating MALOT at 1500Z, Request New York via Track Delta, Flightlevel 350, Mach decimal 85, and maximum Flightlevel 370.


The controller will either acknowledge the request by simply asking you to wait for a moment, or he will read it back if he has any doubts about the clarity, if he repeats it, make sure you listen well and correct the details if needed.


Either way he will say:


ATC: Speedbird 179, roger your request, standby.


The controller will now check to make sure that your requested Speed and Level is requested at the time when you reach the entry point. This may take up to 10 Minutes, so be patient with him and be ready to take your clearance promptly when he calls you:


ATC: Speedbird 179, I have your oceanic clearance, advise ready to copy.


Pilot: Speedbird 179, pass your message


ATC: Shanwick clears Speedbird 179 to Kennedy via MALOT, Track Delta, Flightlevel 350, Mach decimal 85, cross MALOT not before 1455Z


The first part of the clearance is self explanatory. Please note that the controller may impose a time restriction on your crossing of the Entry point. This can be achieved by making use of the FMC Progress page.

A time restriction will only be issued if there is heavy traffic. Nevertheless it is your responsibility to advise the controller of any ETA Changes of more than 3 minutes early or late.

You should do so either by private chat or by Voice, NEVER by text on frequency as this will most likely be lost.


Before I forget, you need to readback the clearance:


Pilot: Speedbird 179 is cleared to Kennedy via MALOT, Track Delta, Flightlevel 350, Mach decimal 85 and MALOT not before 1455Z and track Message 002 (TMI).


ATC: Speedbird 179, readback is correct, return to previous frequency, good day.


Pilot: Thank you, returning to previous controller, Speedbird 179.


Then call the previous frequency.


The above goes also to No-voice flyers, request your clearance by private chat, NOT on frequency.


Along the way Shannon will likely ask you whether you have your clearance, which you must acknowledge and also give him the details of the clearance. He needs to know so that he is able to climb you to your appropriate level in good time.

Shortly before MALOT, you will be instructed to call Shanwick.


ATC: Speedbird 179, Report MALOT to Shanwick radio on 12790 kilohertz, good day.


Pilot: MALOT to Shanwick on 12790 kilohertz, Speedbird 179.


NB. The real radio station works on HF, this cannot be implemented on IVAP, however it's

Still called Kilohertz.




Enroute in the track


When you reach MALOT you should be doing the following actions:


Bring up the progress page in the FMC. There you will find all info the Controller requires from you on the position reports.


You need to report each time you pass a waypoint or 45 Minutes after your last report, whichever occurs earlier.


When you call Shanwick you only state your callsign and “Position report” for a report or “Request” if you have a request.


Pilot: Shanwick Radio, Speedbird 179 with Position Report.


ATC: Speedbird 179, Shanwick Radio, Stand by


Here goes the same again as for the clearance. Do not pass your message till the controller is ready, as he needs to find you in the Management System, if you do it is likely that the data will get lost and you have to start from scratch.


ATC: Speedbird 179, Shanwick Radio, Pass your message.


Pilot: Speedbird 179 has passed MALOT at 1501Z, Flightlevel 350, Mach decimal 85, estimating 53 North, 20 West at 1522Z, 53 North, 30 West is next.


ATC: Speedbird 179 has passed MALOT at 1501Z, Flightlevel 350, Mach decimal 85, estimating 53 North, 20 West at 1522Z, 53 North, 30 West is next.


----Check and correct the controller if necessary, using “negative, I say again”----


Pilot: Readback correct, Speedbird 179, and we request a selcal check, Code Delta Golf

Fox Papa





The Selcal, also selective calling in all essence is a telephone system that allows the controller to page one single aircraft and to spare the crew from having to keep a constant, very tiring listening watch on HF radio.


If you know you plane registration (our today example is G-BYGE, Selcal is DG-FP), you can google for the selcal code. If you wish to use the selcal code, you need to enter both Registration and Selcal code in the Flight plan remarks.


The format for it is REG/GBYGE and the selcal SEL/DGFP.


ATC: Speedbird 179, roger checking on Delta Golf Fox Papa.


The controller will put in the code in his system and transmit, you will hear a gong if successful.


Pilot: Speedbird 179, Selcal check ok.


You only need to check the selcal once.


After this you may put down your headphones, remember to report every 45 minutes!


Finally set Squawk 2000 in oceanic airspace





As the original document states, please DO NOT expect to be able to step climb in the oceanic airspace. The separation involved is too enormous.


You may of course ask for it, you do so by concluding your position report with “Able FL370 at XXXZ (x= time in Z)”.


I however urge you strongly to climb to the highest level you can get to before Oceanic airspace, this causes only a minor additional fuel burn which can be compensated by an additional step climb at the end of the NAT.





After Passing 50° West westbound or 20° West eastbound you will be handed over to Shannon or Gander Domestic Control, you will be assigned a squawk, once Identified you DON’T NEED TO report your position again.


This concludes the section on North Atlantic Tracks





As previously mentioned, the North Atlantic Tracks are only usable for a select number of Destinations. If you keep clear of the NATs you can fly a random route, which is just the Great Circle route with inserted fixes every 10 full degrees of Longitude (I.e 20 West, 30 West etc).


The Random routes tend to be much more Liberal in planning, provided they do not come within 1 degree of Latitude or cross North Atlantic Tracks within their validity time.


Random routes are also used by aircraft flying eastbound during the daytime or westbound during the night-time.


Routes to the Caribbean or Northern South America usually stay well south of the NATs, whereas routes to West coast USA will usually keep well north of the NATs.


Phraseology and flying a random track is almost the same as the NATs with the following exceptions:




• Step climbs are usually possibly as conflicts are rare;

• When requesting or being given a clearance, you need to quote all waypoints from Entry point to Exit point in your flight plan, request and readback;

• The Controller may ask for wind and temperature information;


Below is an example of Air France 3510 (formerly AFR488) from LFPG to TNCM:


N0450F330 LGL UN491 KOKOS UT120 BADUR UN585 REGHI UN480 ETIKI/M083F350 DCT 46N020W 44N030W/M083F370 41N040W 32N050W 20N060W DCT OBIKE/N0445F390 A516 PJM


The IFR clearance is the same with respect to the clearance limit, until the entry point, as is the deadline to obtaining the oceanic clearance: NO LATER THAN 30 minutes before the entry point.


After being asked to pass the message it goes as follows:


Pilot: Air France 3510, Airbus 343, request clearance to Sint Maarten via random routing, EETIKI, 46 North 20 West, 44 North, 30 West, 41 North, 40 West, 32 North, 50 West, 20 North, 60 West, OBIKE , FL330, Mach dec 83, estimating ETIKI at 1320Z


ATC: Air France 3510, roger, standby


ATC: Air france 3510, I have your clearance


Pilot: Go ahead, 3510


ATC: Shanwick clears Air France 3510 to Sint Maarten via random routing, ETIKI, 46 North 20 West, 44 North, 30 west, 41 North, 40 West, 32 North, 50 West, 20 North, 60 West, OBIKE, FL330, Mach decimal 83.


Pilot: Cleared to Saint Maarten via random routing, ETIKI, 46 North 20 West, 44 North, 30 west, 41 North, 40 West, 32 North, 50 West, 20 North, 60 West, OBIKE, FL330, Mach decimal 83, Air France 3510


ATC: Air France 3510, Readback correct, return to previous frequency.





Pilot: Air France 3510, position report


ATC: Air France 3510 pass your message and make weather reports.


Pilot: Air France 3510, passed ETIKI 1320Z, Flightlevel 330, Mach decimal 83, estimating 46 North 20 West at 1340Z and 44 North , 30 West is next, Wind 350 at 20, Temperature Minus 56.


ATC: Air France 3510, passed ETIKI 1320Z, Flightlevel 330, Mach decimal 83, estimating 46 North 20 West at 1340Z and 44 North , 30 West is next wind 350 at 20, Temperature Minus 56.


Pilot: Air France 3510 Read back correct, request selcal check code Hotel Juliet Alpha Foxtrott.


ATC: Roger, check coming up


Pilot: Selcal check ok, Air France 3510


No matter which FIRs of oceanic airspace you cross, the procedure is always the same.





This should cover most of the essentials. This guide shall by no means substitute the standing procedures, but the aim is to simplify them.


For the more seasoned pilots, I have not addressed the Datalink system in this guide for two reasons:


  1. Beginners should be familiar with voice first;


  1. The Datalink system was highly unreliable at time of Print of this guide and it is to be

redeveloped in the near future.


The Datalink system should be used with a good pinch of salt and should there be any

doubt about the message returns, you should call the controller.


publicado por Paló às 20:08

Subscrever por e-mail

A subscrição é anónima e gera, no máximo, um e-mail por dia.

Posts mais comentados
subscrever feeds

Many thanks.
Hi [Error: Irreparable invalid markup ('<br [.....
Entretanto mande-me uma print screen do parque de ...
Olá !O meu email é tw@netcabo.ptObrigado !Capt
Mande-me o seu email, por favor.
Olá !Os meus parabéns pelo blog e pelo magnifico c...
Caro AlexA minha interpretação ao texto que a F1 c...
blogs SAPO