Fuel Line Leak on '48 Ragwing

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sfarringer
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Joined: Wed Jan 12, 2005 10:49 pm

Fuel Line Leak on '48 Ragwing

Post by sfarringer »

On a trip recently, I discovered a problem that could easily have had serious consequences. I believe that this is only applicable to the early ’48 Ragwing, due to the particular interaction of the fuel system and heater system design combination.

During preflight one morning, I smelled fuel in the cockpit after opening the door. Then, found blue stain around the belly inspection port (the one just aft of the gascolator).

What I found is that the flexible heater duct tube was tie wrapped to the 3/8 aluminum fuel line which runs from the fuel valve outlet to the gascolator inlet. The steel wire in the flexible duct contacted the aluminum fuel line (after the flexible duct fabric wore thru), and dis-similar metal corrosion had eaten a pinhole in the fuel line. I believe that a larger leak would have occurred in the very near future.

Fortunately I found it before any consequences occurred. On this long trip, we flew over many, many miles of very desolate, isolated, and mountainous terrain.

And also fortunately, I was able to find the material and tools to fabricate a new line at an airport 2000 miles from home. (The aluminum line and the heater duct are now isolated.)

Note that strapping the flexible duct to the fuel line is sort of a natural thing to do, and it has been that way on this airplane since before I owned it. The flexible duct has pretty close clearance to flight control cables that run thru this area, and you certainly don’t want interference there.

Anyway, perhaps this info of my near miss might be useful to someone else.
Ragwing S/N 18073
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GAHorn
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Re: Fuel Line Leak on '48 Ragwing

Post by GAHorn »

Tying ANYTHING to a fuel line, hydraulic line, oxygen line, etc. for support is a big NO-NO. See FAA-AC 43.13-1b/2b.

Lines, wires, bundles, coaxial cables, conduits, etc etc should be secured with dedicated clamps directly to structure....NOT to existing fuel/hyd lines.

Never use flammable fluid/gas lines for supporting structure.
'53 B-model N146YS SN:25713
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Poncho73
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Re: Fuel Line Leak on '48 Ragwing

Post by Poncho73 »

I know the area well, on my 48 that scat hose is secured with a large adel clamp. The adel clamp and hose are secured to the lower skin and held in place with a PK screw holding the adel clamp. Never tie off to the fuel lines.

If I remember the next time I'm at the airplane I will take a picture of how my heater scat hose is routed and secured.
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Poncho73
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Re: Fuel Line Leak on '48 Ragwing

Post by Poncho73 »

Although it doesn't appear obvious there is a safe gap between the heater hose and the fuel line. You can see the heater hose is held by the large Adel clamp. You might want to try this set up to avoid fuel line chaffing.
Attachments
Scat Hose Fuel Line.JPG
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