If the GPS signal goes down, then I use procedural standards and work a hell of a lot harder, a lot less aircraft get their request levels and a lot of people around the world have a very bad day. Just like the fact that your car may break down so you may as well walk, there's a risk, and you accept that.
Now, a lateral scenario, surveillance, 5nm. Easy. A box of 25 square miles around the aircraft.
Procedural, basic standard is 1nm between the possible positions of aircraft. The best case is GPSRNAV which has a CEP of 7nm. Therefore the best we can have is 15nm laterally between the nominal track of aircraft (7nm for aircraft 1 plus 7nm for aircraft 2 plus 1nm between).
We're coming into wet season out west and while so far there has only been a few WX days, it's coming... Our mate in his nil-ADSB Phenom (or insert any aircraft here) is cruising along at 7nm/minute and trying to get around a line of thunderstorms. The best we can have is 10 minutes ahead and 10 minutes behind longitudinally but I wouldn't run a bare standard then let the lead aircraft go wandering off, no standard anymore if I do that. So it'll be 15 minutes behind and 10 ahead.
To get around storms our mate is up to 100nm off track (if you think that's excessive, go fly out west). That means the lateral tolerance is 107nm (100 on one side plus 7 on the other side).
That box of airspace, 175nm by 107nm 1000ft deep belongs to our mate phenom, no one else goes in there, that's his airspace and his alone. That's 18725 square miles of space that one aircraft is occupying. That's 749 times more airspace than an identified aircraft is occupying.
For a non-ADSB aircraft on track, as mentioned earlier, best case is 20nm ahead, 20nm behind plus 7 either side of track. That's 560 square miles of airspace vs 25 miles if identified. W8, you're right, you do occupy an airspace, and no one else is allowed in that space that you occupy. If you don't have ADSB then best case is you're occupying 22 time more airspace than the next plane with ADSB.
There is still plenty of scope for non-ADSB aircraft to fly around, it's 28000ft deep. If you want to fly higher outside of the J-Curve go to CASA and present you're safety case as to why you should be there.
Gerry111, I am aware that Mr Smith sold his named stores to Woolworths long ago, in the early 80s I think, who have since sold again to some private equity mob. However, it was much easier to fix a power supply or TV in a pinch when bits were available just down the road...
Anyway, again just my insight. Take the fight to the avionics mobs that have dragged their feet for so many years, they're the ones who are unable to supply the required goods.
Last edited by Kieran17; 28th Nov 2013 at 07:18.