On Thu, 18 Aug 2005 09:58:18 -0400, "Peter R."
As far as disadvantages, I am concerned about what might happen with the
sediment in these aging fuel bladders as the fuel empties. But, I have
read articles that dispel this myth so perhaps this is a non-issue.

Maybe this one? http://www.avweb.com/news/columns/182044-1.html

"The Creeping Crud OWT
Then there is the secondary OWT that says something like "But what if some
crud gets sucked into the system from the tank bottom?" Give me a break!
Think about this, for a moment. There are three areas where "crud" might be
a concern. Crud lying on the bottom, crud suspended in the fuel, and crud
floating on the surface. When we fuel the airplane, fuel is injected rather
violently, stirring up the whole tank. When we fly in turbulence, fuel
sloshes rather violently around the tank. Do you really think anything will
be peacefully lying on the bottom, year after year? If it were, why would
running the tank dry stir it up, and if it's that tenacious, how on earth is
running the tank dry going to magically pick it up?

How about suspended crud? It is no more, or less likely to be sucked into
the fuel lines at any fuel level. Floating crud, on the surface? Well,
maybe, but can you name me something that will do that? And if there is,
well, how much of it will you allow, before you rip the tank out for
"cleaning," or how WILL you get it out, someday? Just how, and when, will
you identify it, detect it, and get rid of it? And, how much fuel do you
want as a "buffer" below the floating crud, to keep from sucking it in? In
fact, if there is a little something floating on the surface, I WANT it to
be sucked into the fuel lines, preferably a little at a time, so that the
strainers and filters can catch it, and alert me that something is going on
in there. The likelihood of there being enough to cause a problem is remote,
at best, and if running a tank dry will pick up a little crud, then running
a tank dry often is a very good thing, because you'll catch it a little at a
time, and drain it out the strainer.

Of course, if you keep the tank full most of the time, and the cap on, and
drain the sumps often, there isn't any way for crud to get into, or stay in
the tank in the first place."