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Metal fuel line tubing maintenance


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With all the high time building on our airplanes has anybody been doing maintence or replacement of the metal fuel line tubing?  I was just reading about some failures on the Bonanza list due to fatigue or corrosion. I do not recall any incidents on Mooneys.

I do have some concerns with the tubing  around the fuel pump under the  pilots feet partly because it has likely been fiddled with several time over the years.  I would like to see a drawing or photo on the proper installation and support for the pump and tubing but have never found one.  

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Metal fuel lines fail when subjected to vibration or the wrong person turning the wrench.   The mooney fuel lines are pretty well supported and not subject to vibration.   At some point the rubber fuel line at the wing root should be replaced.    I checked mine and decided the if ain't broke don't fix it rule applies

 

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All metals if subject to vibration have a fatigue life. These parts are seldom examined or replaced and there are instances of improper installation and inadequate support.   I think some of our airplanes originally had Dukes boost pumps that have now been replaced by Weldon.  Does anybody know if these are identical pumps with no changes in tubing or support needed?

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Tubing has a few ways of being manufactured...

And varying materials of construction...

Expect a Mooney fuel line to be different than the others... for better or worse..?

Installation details, leading to life in service...

 

Looks like Clarence’s C customer split at a weld line...?

That is a pretty big leak...

If that were to happen in flight, your Fuel Level and fuel totalizer would have a mismatch that would be hard to believe...

expect strong aroma of fuel if this happens in a Mooney.  Fuel lines are in and around or under the cabin only... not out in the wings...

Best regards,

-a-

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All metals if subject to vibration have a fatigue life. These parts are seldom examined or replaced and there are instances of improper installation and inadequate support.   I think some of our airplanes originally had Dukes boost pumps that have now been replaced by Weldon.  Does anybody know if these are identical pumps with no changes in tubing or support needed?
I just did the swap from the Duke's to the Weldon pump. They make a bolt in kit no mods needed. Only thing noticable is the pump is louder.

Sent from my E6810 using Tapatalk

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On 11/9/2018 at 3:59 AM, carusoam said:

Tubing has a few ways of being manufactured...

And varying materials of construction...

Expect a Mooney fuel line to be different than the others... for better or worse..?

Installation details, leading to life in service...

 

Looks like Clarence’s C customer split at a weld line...?

That is a pretty big leak...

If that were to happen in flight, your Fuel Level and fuel totalizer would have a mismatch that would be hard to believe...

expect strong aroma of fuel if this happens in a Mooney.  Fuel lines are in and around or under the cabin only... not out in the wings...

Best regards,

-a-

Anthony,

While it looks like a weld line, it’s actually the shadow caused by the fuel stream.  According to a fairly large twin Cessna maintenance shop this is quite familiar.  The lines corrode from the inside.

Clarence

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I had replaced the one that runs from the fuel pump to the firewall. It had cracked longitudinally at the compression fitting and was leaking fuel. My mechanic at the time got the part number and ordered another. Came over, put it on, handed me a bill for $150, parts and labor. This was before I enacted the Raptor Methodology© and kept track of my parts, expenses, and assisted with maintenance. Its wasn't terribly expensive for as important as it was. 

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2 hours ago, carusoam said:

Eesh...

Corrosion from the inside gives two challenges...

  • Leaking to the outside
  • bits of oxidized metal moving along the inside, towards the fuel distribution system...

There must be a filter or screen for that...

Best regards,

-a-

In the case of this 340, it was the main line from the tip tank to the fuel selector valve/ strainer filter assembly.  

Clarence

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