There are some GPS procedures which go deep into canyons.
How is the possibility of GPS loss dealt with?
Is there some special “RAIM check” which can be done, to check that satellites will be available in the sky above, for a given location?
A while ago we had a thread here in which it was revealed that there are companies which prepare “escape routes” for engine failures in twin engine jets if this happens after a takeoff, in a canyon. These are apparently based on non-GPS navigation, just in case of GPS loss.
For example, and not suggesting I want to do this, how would one fly a safe GPS letdown into Zell am See LOWZ, from the west i.e. straight down into the canyon?
Not at all likely, in my experience of VFR Canyon flying. But obviously, I cant speak to Waas and approaches under these conditions. But I’ve never seen a ‘loss of satellites’ message in any Canyon and I’ve seen a few!
As someone regularly flying in Austrian valleys/canyons, I’ve never experienced a GPS failure. With the valley at LOWZ being that wide (for Austrian conditions), I would be very surprised if GPS reception is compromised. LOWI is in a valley that is hardly wider and has RNAV aproaches to both runways.
