"Larry Dighera" wrote in message
...
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. :-)


I should have said the "tip tank" Twin Cessnas. Cessna designed it that
way. Fuel injected cars do the same thing but have only one tank to return
the fuel to so it is not a problem. If you wanted to return the excess fuel
to the same tank it was drawn from you would need two sets of directional
valves; one on the supply line and another on the return line that were
synched to each other. It is much easier just to tell the pilot to burn 90
minutes out of the mains before switching to the aux's.

Allen