Dave,  if you have that tank in the cabin you need to go through every possible failure mode.   It's potentially complicated.     I like Bill's idea of using the third inlet except that i had to special order a 3 way valve for my iv so I question that the standard valve has that feature.

If it's less than 30 gallons i would be looking to put the tank in the luggage compartment, well secured to keep it from changing the cg

Colyn Case
802 730 4026

On Jul 11, 2011, at 12:03 PM, Ron Galbraith <cfi@instructor.net> wrote:

> I've flown a LNC4p all across the US and to puerto Rico and back twice using a permanent aux tank in baggage compartment plumbed into return line of one tank using a facet pump to feed fuel from aux tank.   Always used opposite tank when transferring fuel and never had a problem.
>
> RonG
>
> Sent from my iPhone
>
> On Jul 11, 2011, at 9:44 AM, William Hogarty <billhogarty@gmail.com> wrote:
>
>> For Dave Saylor:
>>
>> Dave:
>>
>> I had to cringe when I realized the bag of worms that you seem to be getting yourself into feeding fuel into a partially empty wing tank.  Im not saying that it cant be done but.......?
>>
>> Have you considered plumbing your aux tank directly into the unused (3rd) fuel inlet on the standard lancair fuel selector??   This might eliminate many of the concerns that your presently facing.   Maybe an additional fuel pump just in case???
>>
>> Just a thought.
>>
>> Regards,  Bill Hogarty
>>
>> P.S.  Would like to hear the final outcome, if possible.
>>
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