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Routine Maintenance


JoshMan

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Hey, guys

I was traveling from KDAB-->KHFY today and everything was going great.  The descent was very turbulent and I noted my manifold pressure gauge bounce around for a second and then peg at 30.  I landed no problem and took off the cowling and found a broken manifold pressure line right at the firewall. It was fixed in 15 minutes 

I am just wondering what your routine maintenance consists of. Do you guys perform thorough inspections every 50 hours? 100 hours? etc.

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Hey Josh,

Last annual (my first) we replaced all the brake and oil hoses due to them being hard (no flex). We just finished the second annual and with the cowl off I ran the engine to check for oil leaks and found a rather severe fuel leak. The line feeding the pressure gauge had failed and was pouring over my right side exhaust system. Upon inspection of the fuel lines they all looked fine and were flexible, but this one had developed a hard spot about 6-8 inches long and that's where the leak formed. So inspections don't always reveal a problem. I think hoses are supposed to be replaced every five years. 

 

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You might also consider upgrading your rubber hoses for teflon hoses. The teflon hoses are more durable and are considered to be lifetime hoses. Not sure I would keep them that long but, when you consider that a fuel or oil hose failure can ruin your whole day, why not buy the better, more reliable hose? The extra cost is not that significant. I have them on my airplane.

My IA related a story to me about the first Annual he did on a Comanche. The guys hoses were so old that they literally crumbled in his hands! Hoses are cheap when you consider the total cost involved with having an airplane.

Edited by BKlott
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Per Mooney the 100hr and Annual are the same document.  There are sections of the document that would relate to the Engine and other things under the cowl.  So just saying how often do you do a 100hr is a bit broad.  

We did all the hoses with teflon when the plane was bought.  The ones under the dash were already teflon.  Got the last flexible brake line during the last annual.

When my cowl comes off for an oil change/spark plug cleaning I inspect everything under there.  Are things tight are things rubbing, do all lines go from here to there?  When I got the plane I redid all the hoses under there with teflon.   The last annual the professional mechanic asked for one more support on the MP line so I added another adel clamp. Would I catch a small aluminum MP line with a crack.... probably not.  Maybe when I moved things around.  

There were a fair amount of adel clamps that were missing when I got the plane, I have tried to add those back

After inspecting  I spend some quality time with a flashlight looking around for things that don't connect and then recowl.

 

 

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The 100 hr IS the same as an annual inspection.  It's supposed to cover exactly the same things, but can be signed off by an A&P instead of an IA.,  So essentially, you're just paying for multiple annual inspections in a 12 month period.  

Unless you are required to do 100 hr inspections, I can't even see how doing them would make me feel any better unless I was flying 200 hrs in a year (because psychologically, an annual every 6 months sounds better than 2 annuals a month apart every year).  

I got a little panicked recently because I thought I might have to do 100 hr inspections if I use my Mooney for flight instruction.  Luckily, the 100 hr inspection does NOT apply if you provide the plane, only if the flight instructor for hire provides the plane.

Edited by jaylw314
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Like a Yetti, I used to inspect everything when the cowl was off...

I'm not that active with my maintenance any longer.

My C's MP line broke on the interior side of the FW.

Getting it replaced was a challenge.  The size of calibrated weep hole is hard to get.  It is not well documented on the old Mooney drawings. It is related to the viscosity of air... tiny!  :)

The weep hole is near the gauge.  So the part you replaced doesn't have it...

Best regards,

-a-

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