On Mon, 02 Oct 2006 19:32:15 GMT, "Allen"
wrote in :

Twin Cessna's
are the same way; if you switch to the aux tanks before burning a certain
amount out of the mains (90 minutes for the large aux tanks) the mains will
overfill and vent overboard before the aux tanks are empty.

Are you saying that Cessna designed the fuel system that way, and the
FAA certified it? Or are you referring to a ferry tank?

It makes you wonder if the FAA would certify kinking the fuel line
instead of providing a valve to shut off fuel flow. :-)