Sender: <marv@lancaironline.net> (Marvin Kaye)
To: lml
Date: Mon, 23 Dec 2002 19:47:48 -0500
Message-ID: <redirect-1933595@logan.com>
From: RWolf99@aol.com
Subject: LNC2 Fuel
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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