Hello,

I don't fly Pacific routes so I can't answer that question of who controls who, but when you coast out over the Atlantic, you are under the control of ATC via radio contact through HF radio with Gander Control out of Canada, and then Shanwick Control as you go across the Atlantic. These are just long range radio operators. You contact them with position reports at certain Lat/Long positions as you cross the ocean. You have a set flight plan you have filed for an altitude and airspeed, and you update your position and times every time you call in. If you run into a problem with weather or turbulence as you said, you call the Controller and ask for an altitude change. They will then contact the ATC controllers who will look at your position relative to others around you, and they come back to you to give you a nay or yay. Many times, you can't get different altitudes and have to deal with the turbulence. If it is really bad, they can turn you off the NAT Track and give you a different altitude that way.

GPS only works for the plane that has the GPS receiver onboard. Even within the States, ATC uses radar to see where planes are, not GPS coordinates. Planes know where they are by GPS, but ATC can't see them through the GPS, thus the reason for the position reports. It actually works very well and pretty safely, the really only drawback being the lack of ability to change altitudes and stuff quickly. Now, I have heard of some sort of research going on to use satellites to track planes across the oceans, but I think that is pretty far away.

AD