On Fri, 5 Oct 2007 11:04:50 -0400, "Mortimer Schnerd, RN"
mschnerdatcarolina.rr.com wrote:


Frankly, on a C-172 I can't think of any reason either. But different aircraft
have different systems. As you move up the Cessna line you will find aircraft
that don't offer the "both" option. None of the Pipers do. In fact, I can't
think of a general aviation low wing aircraft I ever flew that offered "both" as
an option.

My Beech can't draw from both.

I've been in Turboprop Cessna Grand Caravans (I know, not a 172) who
would draw fuel from the left tank faster than the right tank, so the
left would be shut off for periods of time to even the fuel.