VFR Cambridge to Blackpool, Netherthorpe-POL leg.
NAVs on POL and GAM, plus hand-held GPS. I'm aiming for a small gap between controlled airspaces, so belt, braces and safety harness.
GPS failure - I had stored POL as a waypoint but not included it on this route (
) so the GPS wanted to take me direct from Netherthorpe to Blackpool. GPS binned for post flight investigation (and GPS route corrected for the return flight!).
Not really a GPS failure, a planning failure. But a serious warning that different technologies have different failure modes and risk factors.
Needless to say my GPS routes are now double checked (as are waypoint coordinates). But I'm only human.....
I have seen GPS interference test notams; I have seen compass errors and NDB/ADF malfunctions, and I've seen VOR unavailable notams. I have not yet flown on a day when a DME service was unavailable, but that is probably an accident of my flying diary.
Nothing is infallible, not even the pilot. Always have a plan B!