twistedenginestarter:
I think your info is a bit out of date.
The (extremely) rare cases where GPS is not available are readily predictable with the present generation of receivers, and therefore the FAA and Transport Canada have approved GPS for both primary enroute and approach phases of flight. TC requires that you must be able to fly a conventional approach (NDB VOR ILS, etc) with onboard equipment at alternate aerodromes only.
As far as comparing the ability of governments to "shutdown" or "degrade" signals, you are correct except for one important point. If I am motoring along over the EU and say France decides to make pipi in my cornflakes by shutting down the nav aids, I will likely know about it by conventional means. The shutdown would also take some time as there is no "master switch" controlling all enroute and approach aids. Besides, I can always say "Je ne give a damn pas" and keep right on going to someplace where things are working.
GPS however does have a master switch, (and a fine tuning knob to boot) and that switch is OWNED at present by the little paranoid guy from Texas (no offense there Texans, but you have to admit his isolationist tendencies even outstrip those of his father). Now ole Dubya (and Slick Willy before him) have said "We ain't gonna touch dat switch", but they also haven't handed it over to anybody either. I guess I can't blame them, they built the system. They could effectively shut down all or part of the world at a moment's notice. During the gulf war (before they made the big promise) they did just that. THAT is the difference. If the Brits decide to do this, they can only affect their own airspace. The USA can affect everybody's GPS, and that is where it is unreliable to the rest of the world.
I've said it before......they have a point there!
