GPS does have a couple of faults. The biggest is it can't tell you are precisely in the 'overhead' of a 10000 feet mountain you erroneously programmed in as Aerodrome X 201 feet amsl.
The other is when it isn't working. Well
a)they nearly always work and
b) you should normally notice that
Groundspeed=0 doesn't fit in with the other bits of your scan.
I would remind you the biggest plus point over
everything else (for private pilots) is they cost £100. Ergo you can have two, or three. Don't tell me two or three different makes of GPS all fail together very often.
If ever.
I should add I suspect lots of people seem to think GPS=MAP. Not so. I don't have a map therefore I can tell when I am 0.01nm from the overhead. The reason is it says
0.01 nm. Much better than any ADF.
