Hi Dene, I think you hit the important points and, without saying it, know that this is yet another of the many "scary old tales" that exist in aviation.
I have flown five different engines in my two homebuilts (something around 1000 hours combined) and I have never had any problems with rubber hose and barb fittings - nor the FAA about those hoses/fittings. On my EFI installation, I use rubber hose made for high-pressure use and double Oetiker clamps (and, of course, fire sleeve). I agree that the barb fittings make removal difficult/impossible so when I have to remove it, I usually replace the hose. For some sections, this is at annual when fuel filters are replaced. I would like to have braided steel lines because they look so neat but the added cost is not worth it to me (something around $500 for my EFI installation). Particularly when the only fuel line related accidents that I have personally seen have involved braided steel lines. Understand, that is not an accident study - just my observations. I suspect a fire-sleeved, braided steel hose will probably last longer under a "direct fire" scenario. In reality, I wonder if that means anything (the guy with the rubber hose is on fire 5 minutes before the braided steel guy but neither of them had any warning so both are in the same pickle) - probably one of a thousand scenarios that a person could lean on. Jon Finley N314JF - Q2 - Subaru EJ-22 http://www.finleyweb.net/Q2Subaru.aspx > -----Original Message----- > From: krnet-bounces+jon=finleyweb....@mylist.net [mailto:krnet- > bounces+jon=finleyweb....@mylist.net] On Behalf Of Dene Collett > Sent: Saturday, December 18, 2010 3:38 AM > To: KRnet > Subject: KR> fuel system fittings > > Guys > I know this is a contraversal and sometimes touchy subject but I need > some clarity. > There is widespread condemnation of the practise of using barbed > fittings and hose clamps in an aircraft's fuel system plumbing. Could > somebody in the know please tell me why this is so. I can't think of > any reason why using a good quality reinforced "rubber" hose with fire > sleeve over it (forward of the firewall) would be in any way inferior > to using aluminuim piping and AN fittings. In the event of a mishap and > things move around, I can't see how the solid installation will be > superior to the rubber hose as it will not have near as much > flexibility to absorb the movement. I would imagine that an aluminuim > pipe would be much more prone to cracking and leaking when kinked. > > Over here the practise of using barbed fittings and flexible hose is > almost universal unless you are assembling a RV kit which comes with > all the appropriate AN fittings. > Am I missing something here? > > Regards > Dene Collett > Avlec Projects cc > Port Elizabeth > South Africa
