I can remember as a teenager (a long time ago!) listening from eastern Canada to flights over the North Atlantic. They used shortwave frequencies that varied based on time of day and time of year. I also sort of remember hearing flight over North Africa.

What happens today? Can a/c communicate with ATC over the Atlantic somehow? ATC software simulates ATC in that area but I keep wondering if it's lying to me.

Jean-Pierre Gagné

I assume some of the airliner comms are now done thru CPDLC or ACARS, but as far as I know they still have "North Atlantic Center" or "Gander Center", "Shanwick Center" etc. etc. on traditional frequencies.

You can go to Youtube and find the PMDG DC-3 flight video over the North Atlantic...it's only a few years old.  I don't think their DC-3 was equipped with CPDLC or ACARS, so they were doing regular radio position checks and they even had another plane relay a message for them to Center, since they were out-of-range at one point.

I think most of the position reports over large ocean areas use HF frequencies.  Some maybe be automated but HF should always work.  I've read a number of accounts of ferry pilots carrying specialize HF equipment that was required for position reports.   The PMDG DC-3 flight in 2019 had a special waver from the FAA so they used VHF to contact high flyers who would relay their information via HF to the controlling stations.  

Yep that's good info, and also, aren't the airliners required to keep at least one comm radio set to a "monitoring" frequency precisely so they can pick up VHF relay calls, or distress calls?    Is that correct to your knowledge?

For the North Atlantic now CPDLC position reports are not just a nice to have, they are a requirement for the organised track system.

Going East bound we get passed from Gander centre to Gander radio on VHF. The VHF guy then gives us the HF frequencies to use, a primary and a backup.

We then just get a SELCAL check on the HF frequency and that’s it , the rest is done via CPDLC and ADS-B until approaching 30 degrees west when we get a CPDLC message from Gander with Shanwick’s HF frequencies. 
 

We get a quick SELCAL check from Shanwick and then go silent again until nearing the ocean exit point shanwick send a CPDLC message with the frequency and the time to check in with Shannon ATC for example AT 0815Z CONTACT EISN ON 127.85

On the 787 you just hit the accept button and the aircraft knows the information so at 0815z the aircraft give you reminder chime on the flight deck, you look down at the VHF radio and the aircraft has entered the correct frequency into the tuning panel scratch pad for you !

It’s very clever.

1 hour ago, Mace said:

Yep that's good info, and also, aren't the airliners required to keep at least one comm radio set to a "monitoring" frequency precisely so they can pick up VHF relay calls, or distress calls?    Is that correct to your knowledge?

Yes we monitor 123.45 which is a common air to air frequency meant for operational use, but more commonly used by American carriers to relay baseball scores. Then on the second box we’ll have 121.5 guard distress frequency.

Thanks for the insight.  

Oceanic CPDLC, which is text based, uses ADS-C (not ADS-B), and is transmitted and received via a satellite link. If it does not work for any reason, the crew would fall back to giving verbal position reports on the HF backup frequencies given by Gander or Shanwick

Edited January 10Jan 10 by JRBarrett

3 hours ago, JRBarrett said:

Oceanic CPDLC, which is text based, uses ADS-C (not ADS-B)

Yes, sorry my mistake.👍

Things have changed a bit since I was a teenager... But the above bring up another point. I remember viewing a documentary re. an Air France flight from Rio de Janeiro to Paris that went down in the Southern Atlantic. The A/P reveived two different readings from the Pitot tubes (one was frozen, didn't have heaters then). Not knowing what to do, it shutdown after sending ACARS to Paris. This means that Air France and Airbus knew immediately the cause of the crash but waited months until be black/orange box was found to explain what had happened. Have I got this right?

6 hours ago, jon b said:

Yes, sorry my mistake.👍

Domestic CPDLC is now being used increasingly in the US for communication with ATC centers. The difference is that the data is typically transmitted over a VHF data radio instead of via SATCOM.

6 hours ago, JRBarrett said:

Domestic CPDLC is now being used increasingly in the US for communication with ATC centers. The difference is that the data is typically transmitted over a VHF data radio instead of via SATCOM.

Yes, as a foreign carrier from Europe we’ve been told we’re not approved to use it and not to try logging on !