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Why a preflight is important.


bradp

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I went to the airport last night to drop off some stuff and wanted to preflight the plane, grab the nav data card to update, etc prior to a planned flight today.

Anyway I found this ...

a9e7bd47baca110a240c63e194587b9f.jpg

I didn't leak test with the boost fuel pump pressurizing, but thought I had enough evidence to remove the offending line. It appeared like there was a minuscule crack at the solder joint at which fuel was leaking.

Removed the offending fuel line and examined more closely.

8d8e34d21cc57270109888b05f56a982.jpg

Yup it's cracked.

If these things didn't cost $100 for 18 inches of 1/8 diameter tube with two poorly soldered nipple ends I'd replace all four. Called my AP today, who was nice enough to talk to me on a Sunday of a holiday weekend - he doesn't have any so we'll install a new one next week.

So much for flying today. :-(

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Brad, Nice catch!

is that fuel dried all over the nearest valve push rod housing?

How did you notice the issue before finding the crack? (Fuel aroma, visually seeing fuel dried, or seeing the crack itself?)

You probably said it, I just forgot the detail...

Thanks for sharing the photos and details.

Best regards,

-a-

Edited by carusoam
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I just saw that the push rod looked black... dried fuel. I'll go back and look at the engine monitor as maybe I was trying to convince myself that #2 was running leaner than usual and that was why I paid attention to it. Usually I don't shine a flashlight up the cowl openings because "hey it's hangared" , but a recent thread on here for me thinking I should be doing inside preflights as detailed as I would if it was an outside rental. And look... I found something.

Go Mooneyspace.

Ok now let's make it a real Mooneyspace thread and add some controversy. [mention=14737]DVA[/mention] other thread this seems like it falls under owner maintenance.

I'd feel comfortable installing the new fuel line if it's truly prefabricated including the proper radius bends. If it's not I wouldn't consider it prefabricated and I'd go to my A&P. Ether way I expect to do the work myself with potential need for A&P supervision. That how I'm interpreting the owner PM reg.

Replacement of the line will be preventing something bad happening to my cylinder or me and my family. :-)

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Once again a great example of an owner, admittedly not a tech guy, opens his cowling and finds something that could have been disastrous.

I am going to work on a video soon that I’ll post in my blog area that shows what an owner/operator, who is not an A&P, can do as an extended preflight. It will be a de-cowling and we will point out what to look for. Someone did this for me, so I want to pass it on.

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28 minutes ago, bradp said:

Go Mooneyspace.

Ok now let's make it a real Mooneyspace thread and add some controversy. [mention=14737]DVA[/mention] other thread this seems like it falls under owner maintenance.

I'd feel comfortable installing the new fuel line if it's truly prefabricated including the proper radius bends. If it's not I wouldn't consider it prefabricated and I'd go to my A&P. Ether way I expect to do the work myself with potential need for A&P supervision. That how I'm interpreting the owner PM reg.

@bradp the FARs for owner maintenance allow you do that replacement yourself if the line is pre-fabricated. I would ask your A&P to be there the first time and guide you, as I think you’re suggesting. This is a simple repair but the fittings on the lines have to be torqued to a certain value and unless you own and are familiar with a torque wrench you’ll need him/her anyway. I would also suggest that you mark the fittings with TorqueLock so you can easily see if they work loose.

Do it all yourself, and you should make the required log entries yourself, just use your A&P as a watch person.

I reference the FAR when I make my entries, here’s an example:

Screen Shot 2017-01-15 at 3.47.58 PM.jpg

Have fun and thanks for sharing your story!

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Thanks Clarence. When I spoke with my mechanic today he thought they came pre bent. What the proper way to form them? Micro tube bending tool required or are spring type benders appropriate ? I glanced at section 4 of 43.13 but couldn't find anything beyond radius guidelines which is also prescribed in the lycoming SB.


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They can be formed around anything with a radius greater than 5/8".  A large socket as suggested, or around an exhaust manifold  which is quite handy to the work area and saves walking.

Clarence

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There is actually an AD note on those fuel lines and clamps. . Must inspect every 110  hours or at overhaul, and also anytime a line or clamp is disturbed or disconnected. 

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf/0/b39e0b81acb0f30786257ecf005d80c7/$FILE/2015-19-07.pdf

Edited by jetdriven
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1 minute ago, jetdriven said:

There is actually an AD note on those fuel lines and clamps. . Must inspect every year or 110 hours whichever comes first, and also anytime one is disturbed or disconnected. 

I take it then, that an owner can legally replace the line, but them must have an A&P inspect it, since it has now been disconnected.

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There are only 189 eight cylinder Lycoming engines in the world registered...

That makes one of us really unique!  :)

Ya know what I'm sayin, Clarence?

Cost of compliance section gave the number of engines effected by this document...  (interesting read)

If you have ever bent brake lines before, this challenge is similar.  I have tried, I took my tool and raw materials directly to my mechanic for completion...  following the existing one will be better than trying to replace a rusty broken one...  the nice curvy bends look like a piece of art if done properly...

Best regards,

-a-

 

Edited by carusoam
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Just thinking about fuel line design and manufacturing - for those who have had experience with both Lycoming and Continental fuel injection systems, how do the fuel injector supply lines differ- why aren't Continentals subject to this AD / issue?


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Looks like the engine manufacturers have taken a simple plumbing task and made it more complex than it needs to be...

The fuel injector system and tubes going to the same four cylinders on thousands of the same engine...   how hard can it be to get robust and precise..?

Getting the right tube, assembled with the right ends, attached in the proper way is a start...

Getting the tube installed properly would help not over stressing the assembly...

If there is a way to tell what killed the tube assembly, that would help determine if any improvements are available.  

Was the tube assembly damaged in manufacturing, or did it get damaged or weakened during installation, or is it a victim of the environment being on the engine?

Often, it can be one part installation and the other part environment.  Some bends in the design are intended to allow for heating and cooling expansion of the cylinders.  Too tight, or not enough bend puts enough stress on the parts to crack and fail...

This is all untested PP ideas.  Not facts from a qualified mechanic.

Best regards,

-a-

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7 hours ago, Brandontwalker said:

I'd spend the $12 on Amazon for one of these when bending $100 lines.

61u5ZOrdwwL._SL1500_[1].jpg

Except that this tool is not designed to bend 1/8" diameter tubing.  Tubing this small made of stainless is not likely to kink or collapse when bent around something fairly large in diameter.

Clarence

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18 hours ago, carusoam said:

There are only 189 eight cylinder Lycoming engines in the world registered...

That makes one of us really unique!  :)

Ya know what I'm sayin, Clarence?

Cost of compliance section gave the number of engines effected by this document...  (interesting read)

If you have ever bent brake lines before, this challenge is similar.  I have tried, I took my tool and raw materials directly to my mechanic for completion...  following the existing one will be better than trying to replace a rusty broken one...  the nice curvy bends look like a piece of art if done properly...

Best regards,

-a-

 

Does your version of the "world" include the parts outside of the USA?  The FAA normally quotes the U.S. fleet and the financial effect on US operators.

There are many more in other countries, albeit not a huge number.

Clarence

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Do you remove the cowling for every preflight?

Nope just showed a flash light in the hole.  Removed cowling once I knew something was wrong. 

The fact that dried up and baked fuel was on the rocker arm tube means I was flying around with fuel spraying over the L cyls last flight.

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Received one of these "Inspection Scope" camera's for Christmas to take a quick look at things like baffle sealing and other mechanics with the cowl installed. About every 5 hours I remove the upper cowl on my J to get the whole picture.

Not recommended for a self medical examination though. No suggestions please.

2309-20_kit.png

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