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Fuel and oil line change interval

Paul 5r4

Well Known Member
Quick question..... Is there a time that fuel/oil lines should be replaced with new?
Mine were the standard from Vans that came with FF kit and have been trouble free for 8 years. I'm wondering if I should as a routine matter replace them at any certain interval. If so, is it after so many hours or so many years???
I'm interesting in the "industry standard" kind of information, not just opinions. I've looked online and can't seem to find any definite answers.
Thanks!
 
For rubber lined hoses---either stainless braid or not, 32 quarters from the cure date. That was the old spec. We dont know the additives in the fuels and oils that may or may not attack the liners, but we've seen it. So----I'd say that if you have rubber lined hoses installed for more than 8 years---might think about changing them.

Tom
 
The two links referenced above don't take me anywhere. Thanks Tom! After chatting with you on the phone, I'll be sending you some pictures tomorrow probably.

Edited. Regarding your link..... I see your "linkey no werky" Didn't for me either. :)
 
I do mine in the 7 year range. There are hundreds, or thousands of planes out there flying with 30 year old hoses. That dosen't make it right, but it does suggest that your plane won't fall out of the sky if you do them at 8, 9 or 10 years.
 
Boy I sure would hate to be the guy signing off the logbook as good knowing that he didnt inspect the hoses. Especially if------
oh never mind--
Tom
 
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IIRC, (and I might not) I think Piper and Cessna say 6--7 years.
I replaced all mine with teflon hoses from TS Flightlines at 6 years. Will never have to do it again.
 
Do we really have enough experience with Teflon hoses to know they are lifetime hoses?

Always trying to learn.

George
 
Hoses

In the Cert plane world these same FWF flammable fluid carrying hoses (non Teflon) might have a manufacturer recommendation to replace at 5-6 years or at engine overhaul. When I worked as a IA and found a hose that was no longer flexible and/or 10 years old or older I would recommend it be changed. Teflon lined hoses live much longer and I’m comfortable out to about 15 years if they look ok and don’t need to be moved. Replacing something (like a oil cooler) might require bending a hose that’s been in a certain position a long time and some thought should be given to installing new hoses if that’s the situation. These hoses perform a critical function and leaks or a failure can be life threatening. I always say 10 years is enough for any rubber part on a aircraft.

Don Broussard A&P, IA, ATP
RV9 Rebuild in Progress
57 Pacer
 
Funny you should say "any rubber part". When I did my panel change, I found the grommets under the firewall shields were brittle and cracked. I replaced two of the five with CPCs but the others are carrying power to the panel (alternator and battery) and the lightspeed ignition harness that Klaus did not engineer with a firewall passthrough in mind. If I hadn't been doing the change, I probably would not have thought about them at all.
 
Counterpoint

I'm not advocating ignoring the recommended replacement intervals of stainless steel braided rubber hoses, but I will offer one anecdotal data point:

I recently replaced all of the AE-701 hoses that I originally installed on my aircraft in 2006 and 2007 with teflon hoses. The original hoses were all genuine Aeroquip and were used with only avgas and aviation oils (Aeroshell to be specific). All of the hoses that were removed all were still very flexible and showed no obvious visible signs of deterioration. However, I now have the peace of mind of knowing that I have all new FWF hoses, infant mortality not withstanding.

To the person that wondered if there is enough experience with teflon hoses to know if they are really acceptable as "lifetime" parts: Teflon has been around for over 60 years, so yes, I believe there is enough experience to know that this is true. However, be aware, that the common definition of "lifetime" doesn't mean the "lifetime" of the owner...it usually means the lifetime of the part that it's installed on. I've always understood that this means that when the engine reaches TBO or rebuild time its "lifetime" is up therefore the "lifetime" hoses should be replaced at that time...

Skylor
RV-8
 
Thanks to each one for your experience and thoughts regarding fuel/oil lines. I've been corresponding with Tom at TS Flightlines and feeling like I'm going to go ahead and change mine out. One reason is they were installed on the plane mid to late 2011. Purchased maybe up to a year before that and perhaps sat on a shelf a few months before I bought them. I'll bet they are 10 years old anyway. Another reason I was thinking of this change is this. After 32 years as an RN, I plan on retiring the end of September. My number one goal is to fly the plane on some nice cross countries. Changing the lines now will at the very least give me a good dose of peace of mind.... and like Steve Smith mentioned, I probably won't ever have to mess with it again.
Again, Thanks!
Edited: I was reviewing the pictures I sent to Tom. On one I could read what I think is the date of mfgr on the tag. If that's what it is...... 11-06! If that IS the mfgr date and they were all bought at the same time.... 14 years. OK, my decision is made.
 
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Double down on cajunwings [#10] above.I've noticed that the teflon lines also 'take a set'. While not as susceptible to internal cracking/ deterioration, the stressing of moving/ manipulating them will affect longevity.
 
The old FAA AC20-7N ( its been chnged to something else now) stated engine hose replacement at 5 years. Certainly this was intended for GA aircraft that flew alot, and used H8794 Mil Spec hose (303/111). Aeroquip and Stratoflex made 601/701 and 156 to use a new version liner with a stainless braid to get more life out of the hoses. Great idea,---opps forgot to tell the fuel companies that were using some supposedly different additives.

We've all seen 'rubber' style hoses have issues. H8794 hoses have a 'rubber' (ok a catch-all term for various liners NOT teflon, like rubber, EPDM, Buna-neoprene, AQP, etc) liner, a nylon reinforcement, a STEEL wire reinforcement, and a cotton outer cover. Well most of you may have tried to flex a hose thats been installed a long time and heard the infamous 'snap, crackle, pop' noises. The cotton cover traps moisure against the steel reinforment wire and it RUSTS OUT. So combine that with a fuel or other fluid that erodes the liner and creates a fracture or a void, and eventually it will leak. Without a good reinforcement, its going to get worse, and eventually could be bad.

Stainless braid 'rubber' is better from a flexibility or integrity standpoint, but the liner is still suceptable to the chemicals in the fluids. (I posted a test hose in another thread that was supposely on a flying aircraft that leaked through the liner.) Teflon is inert to virtually all chemicals in use today. Industrial, bio medical, aerospace, it just works. Higher fluid tempurature capability, higher external temp capability even without firesleeve, generally a higher working pressure are just a few of the attributes. Replace them generally once for the lifetime of your aircraft.

Teflon assemblies DO take some care when removing and reinstalling them. YES---inspect them, especially if they have made contact with structure, or some other object. BUT---generally speaking, teflon assemblies will last the lifetime of your aircraft.

Tom
 
Make it easy on yourself

Just went thru replacement of hoses that were in service since 2003 and also some changes to fuel system so just package them all up ....SEND THEM TO TOM @ TS FLIGHTLINES and rest easy . As evidenced here extremely knowledgeable and I couldn't hope to make hoses as nice as economically or frankly as quickly ! Freed me up to work on other issues . Highly recommended. Cheers. Stew
 
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