"Roy Smith" wrote in message
...

You can keep adding redundency to get the probability of incapacitation
as low as you want, but eventually an event will happen which will take

Even assuming ATC has the manpower and frequency bandwidth to simultaneously
give vectors to all airplanes in an area of GPS outage, do we land nowhere
but runways with ASR approaches when it is IMC in that region until the GPS
service is resolved? And if we want to take off with a void clearance, do
we just consider airports without radar coverage down to the surface to be
unusable during IMC since there would be no navigation system available on
takeoff? Or maybe we just go by dead reckoning on takeoff? What happens if
there is a need for an emergency medical aircraft in a region where GPS is
out of service and no radar coverage is available? Central Pensylvania east
of Johnstown is just one excellent example --- there is a pretty
significantly sized area where there is no radar coverage available for
apporches, so I suppose if sole-nav GPS went out of service in the region
all the airports would just become VFR-only.

Clearly this situation is absurd, and for that reason we cannot and never
will switch to GPS-only navigation. Maybe there will be fewer but
strategically placed VORs and ILS systems but clearly there always must and
will remain some backup system besides just GPS.


--
Richard Kaplan, CFII

www.flyimc.com