"NW_Pilot" wrote in message
. ..

"Allen" wrote in message
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"Jose" wrote in message
m...
The aux tank was connected directly to the engine after the aircraft
fuel system, Not to the wing and the provided documentation and system
description mentioned nothing about the fuel return to the main tanks.

How would the fuel get to the main tanks in the first place? Is the
engine the only connection? (if so, with the fuel selector OFF that
should block fuel flow to the main tanks). Is there a vent line that
connects them?

Excess fuel from the engine is returned to the main tanks. 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.

Allen


And there is a note in the description of that fuel system that explains
that! Which was not included in the description of the modified fuel
system on the 172.

That is true, I am not inferring anything. You would think the tank company
would be familiar enough with the aircraft they are installing tanks into to
have a working (correct) procedure manual. Surely you are not the first to
ferry this particular combination.

Allen