[zig]

In visual conditions it would be a total non-issue - GPS/VOR/IRS guidance to the airport (or radar vectors or pilotage), with a visual landing.

For an ILS approach to minimums in hard instrument conditions, it could be problematic - especially if you are off course and don't realize it. There are minimum safe altitudes on approach plates that could be violated if you are way off course (putting you into a TV tower, for example).

I'm not an airline pilot but I am pilot. I'm not aware of anything better than ILS for those types of conditions (very low ceilings and visibility). VOR/NDB approaches are non-precision approaches. The GPS I have access to does not permit a precision approach - maybe the airliners have something better.

[RockyMcNuts]

You think it would be a problem if the ILS was sketchy in Cat 3 auto-land with ceiling/visibility at minimums ?

But the checklist should check that the ILS is alive... and if it's centered horizontally and vertically the pilots should notice.

OTOH a crafty terrorist could wait for a bad weather day, unplug the airport ILS, and set up an alternate one in a nearby building. Still, the tower would probably notice something was amiss and just say 'go around'.

[lucasjung]

I have heard that the airliners are generally all equipped with GPS units rated for precision approaches. I'd have to look at some approach plates to see how the mins for GPS approaches stack up to the ILS approaches for the same runways (I don't fly anything rated to use GPS for precision approaches).

Don't forget PAR, which generally has mins comperable to, if not lower than, ILS.