Flight routing London to Los Angeles

[Scrutton Street]

I hope this is the right place to ask this question.

I am a regular passenger between London and New York and I have always understood that (and please forgive my terminology which is no doubt incorrect but hopefully you will get the idea) that from about half an hour west of Ireland to about half an hour east of Canada the plane is not under radar coverage - that because it is not over or near land the pilots simply communicate with each other by updating their positions on high frequency radio, and do not get their clearances from the controllers on the ground, until they approach the respective coastline.

Now I have just completed a trip to Los Angeles and noted that the plane flew much further north - over Scotland, Iceland, the middle of Greenland, Baffin Island and north and then western Canada. It was therefore over land most of the way.

Do the same rules apply as on a flight to New York? i.e they overfly all these other places without making contact with ground controllers? Or are they handed from one, to another, to another, always under radar control?

Once again sorry for no doubt what is hideous terminology but hope this makes sense.

[TopBunk]

OK, I'll have a stab at answering you:

1. Over the Atlantic you are out of radar contact by the ATC on the ground
2. Prior to entering any 'remote' area you will have been in receipt of a clearance by ATC that clears you to fly a given routing from a Oceanic entry point (typically via a set of latitudes and longitudes) to the far side of the ocean exit point. eg 50North20West to 52N30W to 54N40W to 53N50W
3. Passing each waypoint a position report is made (either manually or by the aircraft systems) to ATC
4. ATC contact will have been established so that they can call you via a function known as SELCAL which uses a 4 character unique code for each aircraft via HF radio.
5. A dedicated VHF radio frequency exists for pilots to pass relevant operational info to each other (eg how are Australia doing on the test match;), or more likely the Americans passing turbulence reports/rounders scores)
6. The routes between Europe and the Eastern seaboard are decided daily based on the winds and form a set of organised tracks.
7. Routing to the West Coast tends to be outside the organised tracks and naturally will route further to the north, frequently as you describe over Iceland, Greenland, Baffin Island. On these routes it is in and out of radar coverage, and usually mostly using VHF radio comms.

Hope that helps.

[Tim Zukas]

Just to clarify-- when airliners are hundreds of miles out over the ocean, they're not in radar coverage, but they are in radio contact with ground controllers. No idea how much radar they have in Northern Canada but the UK-California flight was always in some sort of radio range, if not radar range.

[TckVs]

Top bunk,

Why not tell him its called the nat track system. You also forgot to mention that Iceland also has VHF selcal if needed, but CPDLC works great if south of 82N.

Keep taking your tablets....

[Liobian]

Hi there; this link may be of some interest, for the UK end. At normal jet altitudes, the radar coverage will be greater than shown, as it's basically operating line-of-sight - as does VHF radio.

http://www.nats-uk.ead-it.com/aip/current/enr/EG_ENR_6_1_6_2_en.pdf

If you look at ENR 6-4-0-2 in the same AIP document, there's a chart of radio coverage over Canada; I'd guess that the chart for radar would be somewhat similar, but broader at height.

[HEATHROW DIRECTOR]

Don't even think about the Pacific!!

[Scrutton Street]

That's a very interesting map - thank you all for taking the time to reply.