On 8/14/2010 11:51 PM, new2coupes wrote:
> I discovered the REAL problem. Apparently, the nose tank removal was
> undocumented.
Here are my random thoughts on this issue.

As previous owner of the "30 Gallon STC", the reason I didn't put it 
into production is because it treats both tanks as a single tank but 
does not include the appropriate plumbing to connect the air spaces in 
the two tanks. Such plumbing is difficult to develop due to the extreme 
dihedral of the wings.  Any tube connecting the air spaces would have a 
low spot in the center section that could effectively prevent it from 
working.  As you have seen, failure of the tanks to properly vent can 
result in running out of usable fuel dispite there being plenty of fuel 
on board.

The solution is simple: a left-right-off valve.  If you cannot 
simultaneously draw fuel from both tanks, there is no issue.

The same issues apply to your system. The only way I would be 
comfortable with it is if it also incorporated a selector valve that 
prevents simultaneous use of both tanks.  I suspect that is the only way 
you would be able to get approved, anyhow.

You will need a field approval.  If you can find a previously approved 
(by field approval) 337 for an identical modification you should have a 
fairly straightforward time of it.  Otherwise, plan on a lot of 
paperwork and probably a lot of money.  A 337 that does not include a 
field approval in block 3, regardless of how it was filed or how long 
the plane has been flying, does not help much unless you are looking for 
other owners in your predicament.


-- 
John Cooper
Skyport East
www.skyportservices.net



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