NAT FAQ: No Datalink – Where can we go?

By Mark Zee


No Datalink – Where can we go?
  • You can make a crossing at FL280 or below, or FL430 or above
  • You can cross via the Iceland-Greenland corridor if you have ADS-B
  • You can enter NY Oceanic, and the Bodo and Azores corridors – but that’s about it.

Datalink is defined as CPDLC and ADS-C. If you’re missing either CPDLC or ADS-C, then you’re not datalink equipped. Since 2021, datalink is mandated (DLM) for the entire NAT region between FL290-410 [NAT Doc 007, Ch 1.8]. The only exception is flights STS/FFR, HOSP, HUM, MEDEVAC, SAR, or STATE.

Without datalink, you can only enter these areas on the North Atlantic FL290-410 [NAT Doc 007, 1.8.2]:

  • Anywhere north of 80N
  • New York Oceanic East
  • The Iceland-Greenland Surveillance corridor
  • The Bodo corridor
  • The Azores corridor

The only complete crossing available is therefore via the Iceland-Greenland corridor. For this, you need ADS-B west of 30W.

So, if you have ADS-B, and the remaining NAT HLA requirements, you can make a crossing at normal altitudes (eg. FL380) through this airspace.

For planning purposes, this area is bounded by the following:
Northern boundary: 65N000W – 67N010W – 69N020W – 68N030W – 67N040W – 69N050W – 69N060W – BOPUT.
Southern boundary: GUNPA (61N000W) – 61N007W – 6040N010W – RATSU (61N010W) – 61N020W – 63N030W – 6330N040W – 6330N050W – EMBOK. [NAT Doc 007, 1.8.5]

If you don’t have ADS-B, then this crossing is not available between FL290-FL410.

In this case, you should plan to cross the ocean at FL280 or below, or FL430 or above. This in turn places you outside the NAT HLA, as the HLA levels are FL285-FL420. A crossing at FL280 may mean a fuel stop, in Iceland for example (BIKF or BIRK are commonly used).

You can request a climb or descent through Datalink Mandated airspace from ATC, and this is commonly granted, but you do need HLA approval.

Santa Maria Corridor

The Santa Maria Corridor will allow you to fly out to the Azores and back, but won’t help with a full NAT crossing due to the gap between Santa Maria surveillance and the New York oceanic boundary. To use this corridor, you need a Mode S transponder with extended squitter for ADS-B. [NAT Doc 007, 1.8.5 b]


This didn’t answer your question?

Comment below. Sadly (for us), we enjoy digging into this stuff. So, post your question below and we’ll update this page with the answer (probably quite quickly!)


Useful links for more on this … 



More on the topic:

More reading:

Mark Zee

Mark Zee

Founder of OPSGROUP, and a former airline pilot, ATCO and flight dispatcher. Based in Christchurch, New Zealand. Email me at


  • Nick Duke says:

    What would be the contingency if you are CPDLC equipped and datalink fails before you coast out into Ganders airspace east bound. Would we have to stay at FL280 and request a fuel stop in Iceland or Shannon?

  • Chris Hollenberg says:

    Is the route CYYR-BGSF still available at FL290-410 if you have both NAT HLA approval and ADS-B but no datalink?

    • Mark Zee says:

      Hi Chris. Techincally yes, it’s available – if you route via GOTA (No DLM applies) and stay out of Gander OCA proper. But, you would likely be running into a lot of crossing traffic on the NAT, so the chances of actually getting above FL290 are strongly reduced. It does depend on NAT traffic on the day, and working something out with Gander in advance makes sense. I’d say overall more likely than not you’d be capped at FL290-FL330 on that route. Let me know if you find out any different?

Leave a Reply

Copy link
Powered by Social Snap