Jose wrote:

3: if you can't update the database (such as you're in the middle of
a
trip during the window) you can't do IMC anymore. BTDT - at
Sun'n'Fun,
no less.

Is this a specific limitation spelled out in Garmin's POH supplement?
Not that I have done this due to burning my own cards and maintaining a
current subscription, but I was under the impression that one could
even fly an approach with an expired database, as long as a) the GPS
supplement doesn't restrict this and b) the pilot verifies the GPS
approach with a published approach plate.

If you burn your own database cards, you will note that the database
update for the Garmin GNS430/530 is normally released (at least here in
the US) ten days or so before becoming current. I suppose it is not
unrealistic to be away from home longer than ten days, but that does
provide some amount of time to plan for the expiration.

BTW, you raise some excellent points about the GPS being a single point
of failure. I also have also experienced three different GPS problems
during three different flights that rendered the unit inoperative for
five minutes or so per event. One was my fault, as I opened a bottle
of water at altitude that sprayed all over the GPS, thanks to the
pressure difference. The MSG button temporarily shorted out and I
could not see any page except the message page.

The other two problems were GPS software related. Of these two, the
notable one occurred when the database card I had in the unit became
*current* during my flight (at the crack of 00:00z of the new day - I
had placed the card in a day early for the flight). This was a
Bendix-King KLN-94 GPS and at the crack of 00z, a message appeared
stating that the unit needed to be rebooted due to the database
becoming current. Ridiculous of the unit to do this, but it caught me
with my pants down as the unit could not acquire satellites right away
upon rebooting. IMC at night and I did not have the VORs set as
backup. I scrambled to set up my VORs and only managed to drift off
course by a mile or two before getting back on course. That was a good
lesson.

--
Peter