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> >
> Greetings, I have had a problem with fuel siphoning from my right fuel
> vent
> since new(3 years) . It is only on the right side, only when full, and
> stops after I have flown the 1st 1/2 hour off that side. I'm sure some of
> it might be that I'm not perfectly coordinated, but even when I pay real
> close attention to the ball I get intermittent flow in even the lightest
> turbulence.During the test period I even went as far as putting a 90
> degree
> turn tube directly into in air flow.---No better. My vent tube is per
> design with a 45 degree cut facing forward, and I fly a 320. If anyone has
> had any experience with a problem like this ,I sure would like to know the
> solution. Sincerely, Fred N9BF
>
Fred -
  I've meant to respond for a few days now, but have just now had
time.
  My wing tank vents are per the manual also, with a 45 degree cut
facing forward. I located the vent tube as high as possible against the
upper wing skin. I don't have fuel in the outer bay and you didn't state
whether you did or not; but if you do, that would make leaking overboard
more likely, since the fuel would have less distance to travel "uphill".
  On my 320, I've noticed that if I "squeeze" in that last gallon
of gas in either  wing tank, it takes only a slight tilt on the ground to
spill and if it didn't spill on the ground, it would surely do it in the
air. The wing tanks just seem to be sensitive about spilling off that top
gallon. I thought about installing a device to prevent that, such as a check
valve, during construction, but decided against it, or anything else, in the
vent tube. It would just be asking for a more serious problem later.
            Bill Rumburg
            N403WR  (Sonic bOOm)