Navigating Across the Big Pond

Aviation Airlines
1

May have been discussed before, but travelling between the East Coast US and Europe many times, I’ve always wondered just what sort of air traffic control exists when leaving Canadian air space and then flying out over the Atlantic until control is reestablished say, by Irish air traffic control. Vice versa, coming back to the US.

Listening in on United’s passenger ATC audio, one typically hears something like this from the Canadian air controller after passing over St. John’s, or Gander: “Radar coverage terminated. Good night!”

Oh, so he or she might as well say “Aviation Canada wishes you a pleasant journey” [like the wonderful folks on the Swiss railways], but from here on out, you’re on your own buddy! Hope you make landfall over Shannon!"

About now [noon EST], one can see the map for, say Goose Bay, Riviere-Du-Loop, or Baie Comeau, filled with the first big concentration of European flights headed for the US. Many flights, one right behind the other, maybe at different flight levels, many not. I guess they all kept themselves separated from each other! How did they do that?

Is there some radar or some visibility over ever airliner all the time over the Atlantic? Once the pilot is let go, so to speak, by the Canadian or Irish controller, can the pilot, if encountering turbulence, bad weather, whatever, decide to go up or down, left or right to avoid the problem? Must they get permission from someone? If so, from whom?

Or, is it that once you leave radar coverage, you must, must stay exactly as you had filed in your flight plan? No changing altitudes midstream. No deviations from the exact route you had filed. “I know it’s rough out here, but sorry folks, we’ll be close enough to Shannon in only a few more hours, where we can get permission to deviate! Have another Gerolsteiner! Sorry!”

2

The Wikipedia article on NAT Tracks covers the topic pretty well.

3

Mduell,

Thanks for the reference. I must say, to me it doesn’t sound all that sophisticated given today’s technology. It seems that there’s a lot of modernization that could/should be made in air traffic control.

4

You’re right, but it works.

5

Definately not cutting edge technology, but we’re making advances. More and more, especially among corporate and newer airline equipment, the communications are done through satellite phones or sat uplink units. Beats the hell out of trying to get someone on the old HF radio.

6

I’ve done maybe 15 round trips in a couple of biz jets over the years. The Wikipedia article is good although there is one mistake. Selcal does not open the squelch as stated. What Selcal does allow you to do is turn off the audio (NOT the radio) so you don’t have to listen to the HF continuously. If ATC needs you they transmit a code that your onboard Selcal receives via the HF radio then sounds an alert in the cockpit. You then turn your audio back on, and answer the call. The Selcal box is wired between the HF (and VHF on some aircraft) and the audio panel. The HF does have to be on and tuned to the proper frequency to work.
Typically you make position reports every 10 degrees of longitude, which is about 45 minutes depending on ground speed. In the Western Atlantic New York and Gander control most of the airspace to 30 degrees west, while Shanwick controls east of 30W. There are several other controlling agencies, like Reykjavik, that have smaller control areas also.
Someday, maybe, I’ll fly an airplane with satcom and data link…

John

7

If they can put XM and DTV on airliners, why not a trans-Atlantic (Pacific) Satcom system for ATC? I’m no techie, but really, how difficult would that be?

8

Probably cost factor and coordination with other country ATC systems I would think be the main barriers.

Allen

9

As far as putting it in the airplane I fly now, cost is the big thing. We are down to maybe one trip per year, if that. Not really worth it. As far as upgrading ATC facilities again Allen is on the right track. Cost to the taxpayers is usually a big holdup. Oakland Oceanic controls a huge chunk of the pacific, they did add datalink a few years ago which is a big improvement. It enabled them to redo all the airways, reducing the distance between them thus increasing the number of aircraft per hour.
I saw a thing on TV a few years ago, Aukland has a radar-like display for their oceanic controllers. The datalink updates something like once a minute so it is very accurate.

10

Most of the Big Metal transoceanic flights are using GPS and Satcom for navigation and communication. A lot of the communication to pilots is done through a datalink system that prints the message in the cockpit and they reply in the same way. They can also talk to controllers through the satellite systems(a big expensive mobile sat phone). The GPS network is very accurate(a few metres). Flight plans are preloaded in the flight management computers and with the inputs from the satellites the aircraft follows it’s course like a bloodhound on a scent.

11

Even as we speak the FAA is putting into place a sattelite based ATC sytem over the North atlantic.

12

Was more fun yesteryear…HF position reports, dead reckoning and a periscopic sextant. Primitive, but rewarding!

13

We still fly steam gauges but have two GPS/FMS’s with a single INS as the third LRN input, but still use the HF for Com.