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From: Hughes.WBST@XEROX.COM
Newsgroups: net.aviation
Subject: Re: Switching Fuel Tanks
Message-ID: <860314-043432-1554@Xerox>
Date: Fri, 14-Mar-86 07:34:00 EST
Article-I.D.: Xerox.860314-043432-1554
Posted: Fri Mar 14 07:34:00 1986
Date-Received: Sat, 15-Mar-86 21:17:15 EST
References: <5111@alice.uUCp>
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The ARPA Internet
Lines: 16

"You still want to be able to use only one tank in case drawing
fuel unequally from the two tanks causes a weight unbalance during
extended cruising flight."

To avoid this you fly with the wings level.  When you fail to do this
for a while you can tip the wings a bit (raise the one with the most
fuel) and the fuel will follow the old rule that a liquid seeks it's own
level.  What you did not mention and to me is a stronger reason for
switchable tanks is what happens if you have lots of fuel but the engine
sputters or quits.  It could be due to water in one tank.  With the fuel
selector you can try the other one.  Without the selector, you look for
a place to land real quick (you probably do this any time something
uncool happens--- if you are not always looking for a place to land just
in case, which is an excellent idea).

Bill