"As most will know the aux tanks (which are in the wings & locker where fitted) ought not to be used 'till approx an hrs worth of fuel has been used from the mains (Tips) This is due to the fuel pumps supplying a higher than required fuel flow to the engines & thus the excess not required by the engines is returned to the Tips (Mains). I could be wrong there but am sure I'll be told as much by a more current Cessna driver:-)"
Correct. The fuel is returned to the mains regardless what tank is selected. yes it is about an hour out of the mains first otherwise when the main tank is filled with the returned fuel it will vent overboard.
the fuel system is the same as the 401/402 A & B it is not the same as the C model. I believe the C model is just left and right mains only. not sure though.
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