IO540,
if you were doing an NDB approach, and you had a GPS also, and the ADF was telling you that you will live and the GPS was telling you that you will die, which would you trust?
Just a wee tangent to keep us entertained
I guess the answer very much depends, does it not? You can't really compare a belt and braces 430/530 type GPS system to a cheap and cheerful Skymap. I don't think it is fair to say that an NDB would be less accurate than the aforementioned Skymap, certainly not in my , admittedly limited, experience with the Skymap GPS! Another problem with GPS is there is no way of quantifying the error, if it is wrong there is nothing to suggest that it could be wrong(unless you are transported to a completely different part of the country/world). Probably a tennuous argument, but you can pretty much guess when the ADF maybe telling porkies.
Prehaps I've been tainted by my experience of GPS telling me where I knew I was not in my formative hours
