Trans-atlantic / other flights...

[pilotezulu]

I guess my knowledge is limited to a PPL, and I was curious to know how trans-atlantic and other flights over large water bodies (mainly across oceans) operated.

Mainly in terms of --

1) Navigation - Do they have VORs or beacons to track that are in the oceans?

2) Frequencies - What frequencies do they use and what is the transition like? Is there an "oceanic" or some common frequency that is governed centrally or do aircraft transition frequencies governed by certain nearby countries/continents?

Just curious. If someone has any good answers, I'd love to hear 'em.

Cheers.

[Fernando_Covas]

To navigate aircraft use whats called NAT tracks. These are basiclly coorinates and change daily. Run a search on google for nat tracks.

[HEATHROW DIRECTOR]

Navigation is carried out by Inertial Navigation Systems or GPS(?)

Communication is by VHF and then HF SSB. The North Atlantic ocean is divided into sectors with various control authorities resident in the adjacent countries.

They're very basic answers but I'm sure that if you want more detailed information there are plenty of people on here who will help.

[slingsby]

Land based VOR/DME equipment doesn't have the range to transmit over oceans, therefore, points in the ocean at a given longitude and latitude are given names, airways are projected between them and hence you have a point to point oceanic navigation. On board the aircraft, the inertial guidance system, which you program in prior to leaving the gate with it's position (exact long/lat) and enroute navigation points (VOR/DME/ADF etc) along with the position fixes, which someone with no other job gives silly names to allows you to plot your course accurately over oceans.
So long as you know where a navigation point is (with long/lat) there is no real way of getting lost unless your onboard equipment fails or you programmed it in incorrectly. Most FMC's (onboard computers) are preprogrammed by the navigation department with the relevant data, so your main task is to set the start co-ordinates accurately, then enter the planned route, your FMC will tell you if there is a route discontinuity, this is where cross checking with the other crew member comes into it's own. One enters the info, and the other cross checks it.

Communication is via HF over oceans, and over some land areas as well. It is a high frequency signal bounced off the atmosphere to a large attenna array on the ground. Sounds crappy when you use it, but an essential part of radio and communication. Sometimes when certain atmospheric conditions prevail, signal and reception is poor, which then as an unwritten rule, other aircraft act as a radio relay. You talk to the other aircraft and they use their better signal to relay the information. Over land it tends to be better, as VHF has good coverage, also the use of radio repeaters is used to enhance reception and transmission.
Hope this helps

[rotornut]

Flying the Big Jets by Stanley Stewart gives a detailed account of a flight from JFK to LHR in a 747-400. It gives all the details of trans-oceanic navigation as well as all the other stuff relating to the operation of big airplanes. It is written for the layman and is very readable and highly recommended.

[sf25]

this might also be of help: http://www.bcavirtual.com/crossing_the_north_atlantic.htm

rgds and fly safe

[rotornut]

there has been reports that Vortex wake, has hit aircraft flying a 1000ft below just behind the lead aircraft.
What if the 380 starts flying the Atlantic?

[Rainboe]

By the time the vortex has sunk 1000', it really isn't a problem for a large jet. When it has happened rarely across the Atlantic or any other airway, there is just a little bouncing around with hardly any lateral motion. You just steer the autopilot a few degrees to get out of it. The core rotation has largely dissipated by the time the vortex has sunk- it's just lightly eddying air then. Remember, any more of a crosswind than a few knots will blow the vortex out of the way by the time it has sunk.