Oceanic Clearance

International Operations Manual

Eddie sez:

You might argue that getting your oceanic clearance isn't rocket science and is hardly worth a page of its own.

I would like to build a database of various locations in the world and a sentence or two about how one gets an oceanic clearance. It can serve as a heads up and confidence builder for others. If you can add to this data base, please hit the "contact" button and let me know.

The busiest oceanic area in the world is the North Atlantic, no doubt about it. It is no wonder they have the most exhaustive guidance on the subject, and much of it applies to elsewhere on the globe. It is valuable stuff, even if you never fly in the North Atlantic.

Everything here is from the references shown below, with a few comments in an alternate color.


Figure: Oceanic Clearance, from Eddie's notes.

Last revision:


The Three Elements of an Oceanic Clearance and When it Must Be Obtained

I think the three elements are self explanatory but the when question seems to vary from place to place.

[NAT Doc OO7, ¶5.1]

  • There are three elements to an Oceanic Clearance: Route, Speed and Level. These elements serve to provide for the three basic elements of separation: lateral, longitudinal and vertical.
  • Oceanic Clearances are required for all flights within NAT controlled Airspace (at or above FL60). Pilots should request Oceanic Clearances from the ATC responsible for the first OCA within which they wish to operate, following the procedures and the time-frame laid down in appropriate AIPs. Such clearances, although in most cases obtained some time before reaching the Oceanic entry point, are applicable only from that entry point. It is recommended that pilots should request their Oceanic Clearance at least 40 minutes prior to the Oceanic entry point ETA except when entering the Reykjavik area from the Scottish or Stavanger areas, then the clearance should be requested 20 minutes before the Oceanic entry point ETA.
  • While this is written for the North Atlantic, the guidance is pretty universal: look at the country's AIP for the real answer. But in general ask at least 40 minutes out. If you are on the ground within 40 minutes of the entry point, you will probably be getting your oceanic while on the ground.

  • To assist the OAC in pre-planning optimum airspace utilisation, when requesting an oceanic clearance the pilot should notify the OAC of the maximum acceptable flight level possible at the boundary, taking into account that a climb to the assigned oceanic flight level must be achieved prior to entering oceanic airspace and normally whilst the aircraft is within radar coverage. The pilot should also notify the OAC of any required change to the oceanic flight planned level, track or Mach Number as early as practicable after departure. If requesting an OTS track, the clearance request should include the next preferred alternative track.

How to Obtain Your Oceanic Clearance

This guidance is fairly generic with North Atlantic particulars. I'll add specific guidance for other areas as I get it.

[NAT Doc OO7, ¶5.1.4] Specific information on how to obtain oceanic clearance from each NAT OAC is published in State AIPs. Various methods of obtaining Oceanic Clearances include:

  • use of published VHF clearance delivery frequencies;
  • by HF communications to the OAC through the appropriate aeradio station (in accordance with the timeframes detailed in paragraph 5.1.1 above);
  • a request via domestic or other ATC agencies;
  • by data link, when arrangements have been made with designated airlines to request and receive clearances using on-board equipment (ACARS). Detailed procedures for its operation may vary. Gander, Shanwick, Santa Maria and Reykjavik OACs provide such a facility and the relevant operational procedures are published in national AIS and also as NAT OPS Bulletins which are available at www.icao.int/EURNAT/, following “EUR & NAT Documents”, then “NAT Documents”, and folder “NAT OPS Bulletins”. New York OAC uses the FANS 1/A CPDLC function to uplink oceanic clearances to all aircraft utilising CPDLC.

[NAT Doc OO7, ¶5.1.5] At some airports situated close to oceanic boundaries or within the NAT Region, it may be necessary to obtain the Oceanic Clearance before departure. These procedures are detailed in relevant State AIPs, which should be consulted prior to departure. On the east side of the NAT, this will apply to departures from all Irish airfields, all UK airfields west of 2° 30'W and all French Airfields west of zero degree longitude. Oceanic Clearances for controlled flights leaving airports within the region are issued by the relevant ATS unit prior to departure.


[Jeppesen Airways Manual, Atlantic, North Atlantic (NAT) High Level Airspace (HLA)] Unless otherwise advised by ATC the following Oceanic Clearance Delivery (OCD) procedures are in effect daily from 2330/0730 UTC for eastbound Flights (including data link equipped air­craft) operating above FL280 that enter the Gander Domestic FIR/CTA. Clearance delivery fre­quencies will be published daily in the remarks section on the eastbound NAT Track Message. Pilots are to contact "Gander Clearance Delivery" on the frequency for the track/route as per the NAT Track Message to which the aircraft is proceeding. Contact clearance delivery within 200NM of the specified clearance delivery frequency location. If contact cannot be established, advise ATC on the assigned sector control frequency.

[Jeppesen Airways Manual, State Rules and Procedures - Canada, ¶11.8.3]

  1. Unless otherwise advised by ATC, the following oceanic clearance delivery procedures are in effect daily between 2330 and 0730 UTC (DST 2230 and 0630 UTC) for all eastbound oceanic flights (including data link equipped aircraft) operating above FL280 that transit the Gander Domestic FIR/CTA:
    1. Clearance delivery frequencies are published daily in the "Remarks" section on the eastbound NAT track message. Pilots are to contact Gander Clearance Delivery on the frequency for the track/route as per the NAT track message to which the aircraft is proceeding. Contact with clearance delivery should be made within 200 NM of the specified clearance delivery frequency location. In the event that contact cannot be established, pilots are to advise ATC on the assigned sector control frequency. The following frequencies and frequency locations will normally be used:
      • Natashquan (YNA) (50°11 'N 61 °47'W) - 135.45 MHz;
      • Allan's Island (46°50'N 55°47'W) - 128.45 MHz;
      • Churchill Falls (UM) (53°35'N 64°14'W) - 128.7 MHz;
      • Stephenville (YJT) (48°34'N 58°40'W) - 135.05 MHz;
      • Sydney (YQY) (46°09'N 60°03'W) - 119.42 MHz;
      • Brevoort (62°20'N 64°08'W) - 132.025 MHz;
      • Kuujjuaq (YVP) (58°05'N 68°25'W) - 134.2 MHz.
    2. For those operators that do not receive the NAT track message, pilots are to contact Gander Clearance Delivery when within 200 NM of the frequency location. In the event that contact cannot be established, pilots are to advise ATC on the assigned sector control frequency.
  2. Pilots are to maintain a continuous listening watch on the assigned control sector frequency while obtaining the oceanic clearance.
  3. Unless the flight has received the message "CLA RECEIVED CLEARANCE CONFIRMED END OF MESSAGE," data link oceanic clearances must be verified with Gander clearance delivery during the times indicated above. Outside the indicated hours, oceanic clearances are to be verified on the appropriate control frequency.
  4. ATC will not normally advise pilots to contact Gander Clearance Delivery. There is no requirement for pilots to confirm receipt of an oceanic clearance (including a data link oce­anic clearance) from Gander Clearance Delivery with the assigned control frequency.
  5. Due to frequency congestion on both the clearance delivery and sector control frequencies, pilots should refrain from unnecessary lengthy discussion with respect to oceanic clearances and procedures. Constructive comments and complaints should be processed postflight through the company operations.
  6. Procedures and further information for flights intending to receive oceanic clearances via data link are published in Gander Datalink Oceanic Clearance Delivery (OCD) Crew Procedures.


[NAT OPS Bulletin 2015-02]

  • The Reykjavik Oceanic Area Control Centre (OAC) provides an air traffic control service within the Reykjavik Oceanic Control Area (OCA). Data Link Oceanic Clearance Delivery (OCD) service is provided via VHF and satellite to ACARS equipped aircraft via network service providers ARINC and SITA. If the flight crew is uncertain about any aspect of the data link OCD process, they should contact:
    • Iceland Radio on HF, VHF or SATCOM voice; or
    • Reykjavik Control on VHF.
  • The OCD transaction is initiated in all cases by a downlink oceanic clearance request (RCL).
  • Any RCL must contain the following information, as a minimum:
    • Reykjavik Entry Point.
    • ETA for Entry Point.
    • Requested Mach Number.
    • Requested Flight Level.
    • Note: If the flight planned route does not contain a waypoint on the Reykjavik CTA boundary then the Entry Point should be the next flight plan waypoint before the Reykjavik CTA boundary. In such cases the entry point in the CLX message will be a system calculated boundary crossing point and this change will be highlighted with the text “ENTRY POINT CHANGE (position)” in the ATC/ line. Exceptions to this are the waypoints EPMAN, DARUB, JULET and LT.

  • Upon receipt of a valid CLA message, the Reykjavik FDPS will uplink a Clearance Confirmed message. This message indicates that the data link oceanic clearance process is complete and that no further action is required by the crew to acknowledge or verify the oceanic clearance. The clearance transaction is not complete until the confirmation message is received.
  • The OCD service is not available for flights departing from airports in Iceland, Greenland and the Faroe Islands. The oceanic clearance to those flights is delivered by the appropriate Control Tower or AFIS before departure.

Santa Maria

[NAT OPS Bulletin 2013-01]

  • According to the procedures and time frames published in AIP Portugal, the pilot requests his OCL through the ACARS terminal using the Request Oceanic Clearance (RCL) message. The RCL message includes the same information elements as a voice request.
  • The ATC ground system will acknowledge the reception of the request and verify that it corresponds to an existing flight plan. If negative, a message will be sent, rejecting the RCL.
  • If the flight plan exists the ATC ground system issues the oceanic clearance and sends it to the pilot via the ACARS data link network. The pilot can check and print the clearance at his convenience.
  • The pilot sends back a clearance data link acknowledgment (full read-back).
  • The read-back is checked by the ATC ground system against the issued clearance and sends either a clearance confirmation or cancellation, depending on the result.
  • When a valid data link oceanic clearance is received, pilots must send a Clearance Acknowledgement (CLA).
  • After sending the CLA the crew should expect a confirmation message from ATC ground system.
  • If no confirmation is received within 5 minutes of sending the CLA, then the data link oceanic clearance must be verified via voice.

Shanwick (Westbound North Atlantic)


Photo: ORCA system overview, NAT OPS Bulletin 2010-006, Appendix A
Click photo for a larger image

[NAT OPS Bulletin 2010-006]

  • Shanwick provides a Westbound Oceanic Clearance Delivery service via Datalink to aircraft fitted with an appropriate specification of Aircraft Communications, Addressing and Reporting System (ACARS) equipment. This service is known as Oceanic Route Clearance Authorisation (ORCA).
  • ORCA is configurable to accommodate variations in airline datalink communication capabilities. The principle operations are:
    • datalink readback of clearance
    • voice readback of clearance
    • Datalink readback is the preferred mode of operation.
  • Any RCL must contain the following information, as a minimum:-
    • Shanwick Entry Point.
    • ETA for Entry Point.
    • Requested Mach Number.
    • Requested Flight Level.
  • Crews should add remarks (RMK/) indicating the preferred alternative to the requested clearance and maximum flight level that can be accepted at the Entry Point. Inclusion of this information greatly assists the Shanwick Controller and expedites clearance delivery process.
  • The RCL must contain the same callsign format as the current filed flight plan.
  • Aircraft must not enter Shanwick Oceanic Airspace without a clearance.
  • Crews should request Oceanic clearance not more than 90 minutes flying time from the OCA boundary. RCLs outwith this parameter, will be rejected.
  • Crews should request Oceanic clearance not less than 30 minutes flying time from the OCA boundary. RCLs outwith this parameter, will be rejected.
  • If a flight is within 15 minutes of the OCA boundary and no clearance has been received, the crew must contact Shanwick by voice and advise the ATC authority for the airspace in which they are operating.
  • Crews requesting via ORCA must contact Shanwick by voice if no clearance has been received within 15 minutes of making a request for clearance. It is the responsibility of the crew to monitor this time period.
  • The crew should expect an advisory message from ORCA within 5 minutes. If this is not received one further attempt to downlink an RCL can be made (provided the 30-minute parameter, above, can still be met). If this second attempt to downlink the RCL also fails to generate an advisory message the crew must revert to voice procedures.
  • The ORCA clearance message (CLX) shall be uplinked to the aircraft and shall contain the following information as a minimum:-
    • Callsign
    • Shanwick Boundary Entry Point and ETA.
    • Flight Level.
    • Mach Number.
    • Route information i.e. full NAT Track or Random Route details.
    • Destination.
  • For those aircraft equipped to downlink a datalink acknowledgement (CLA) for the CLX, the crew must send this message as soon as possible.
  • This CLX must be acknowledged. Should the crew require an alternative to the issued clearance, they must request again.
  • Upon receipt of a valid CLA message, ORCA will uplink a Clearance Confirmed message. The clearance transaction is not complete until the confirmation message is received. If the confirmation message is not received, the crew must contact Shanwick by voice.