I trained in and flew 172s for years out of an airport with a field
elevation of 5900 feet. No one on the field ever heard of this placard; no
one ever operated the planes on any fuel setting other than "both" (though
we filled the tanks with the selector on a single tank to prevent
cross-flow); and I don't recall anyone ever having a fuel starvation
problem.

Maybe it's the notorious Arkansas Triangle?

Seth

wrote in message
oups.com...
Thanks for all the updates guys...looks like single tank over 5000 it
is....