In the real world there's no reason as to why you couldn't use the GPS as an overlay for any ground based approach. As long as the A/C is fitted with that type of approach such as an NDB/VOR & the PIC is qualified & that approach proceedure is used as primary tracking guidence then I see no reason as to why not follow the GPS tracking info as long as yr within tollerances with ref to the ground based aid/s. Just my thoughts
CW
yeh Dr (how ya doin'?) I did actually loose all sat signals many years ago now whilst navigating to an outback station in a PA42. I was flying at FL's with lots of smoke haze around (Bungle Bungle area) & to have to 'map' read after being spoon fed for a while by way of the GPS wasn't fun !
