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Angier -
What you've heard so far is that Tee-ing upstream of the Facet pumps, with or
without a ball valve in that crossfeed line, won't work. Respectfully, I
don't fully agree. Nor do I think this is the best solution, but it's pretty
good! Here's my rationale...
What you are trying to do is be able to pump the fuel out of wing tank A when
Facet pump A fails. If you have the T in the line, connecting the tanks
together upstream of the Facet pumps, then you will be able to do just that
by opening the valve that connects the two pumps. Pump B will suck the fuel
out of tank A. However, this won't work when EITHER tank is empty, since the
Facet pump will suck air if it can, and not pump any fuel.
The only time this is a problem is when one tank is empty. Doesn't matter
which one. As the other guys say, one tank will empty before the other, and
there's nothing we can do about this. However, when one tank is empty, the
other one would be nearly empty, won't it? (You guys who are flying need to
answer this.) So maybe this drawback is not so bad.
What you'll have with your concept is the ability to pump fuel out of the
tank with the failed pump, but only until either tank is empty. Then you
close the crossfeed valve and the only tank you get fuel from is the one with
the working pump. I think this is a pretty simple system. I like it. Maybe
you can't get the tanks 100% dry but at least you can get the lion's share of
it. And certainly you'll get more fuel than if you don't have the crossfeed
valve at all. Besides, with the header tank you have another hour's reserve.
(If you don't have a header tank, don't do this...)
Hey guys, you land right away if your fuel system isn't working, don't you?
Angier won't open the valve unless one pump isn't working, then whatever
extra fuel he gets is gravy. He then sleeps on the ground until Vern FedExes
a new Facet pump to the FBO wherever he happens to be. Bolts it in by 10:30
am and continues on his merry way...
My question is this. How will you know when a pump fails?
- Rob Wolf
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