Observed corrosion on a candidate J model.

[EricJ]

A J model I'm looking at as a purchase candidate has lived the last twenty years in the desert southwest.   The airframe generally looks very good, but I did find these spots that I'm not too sure about.   The first pic was taken through the inspection plate at the wing root just in front of the flap on the left wing.   The second is the spar from inside the wheel well.     I tend to think that neither of these is horrible although I do want the stuff in the wheel well looked at better, but I wanted to run it past the experts here and see if I'm missing anything or just to partake in the wisdom of MS.

Note:  the top pic got turned upside-down somehow.

 

 

 

Edited April 12, 2017 by EricJ

[AndyFromCB]

Is that a spider in the photo? That would make the plane automatic no-go according to my wife. Actually, she would probably require the entire airport get nuked.

Edited April 12, 2017 by AndyFromCB

[Ben E.]

I'll let the more experienced guys comment on the possible corrosion but thought I'd say please be careful. That looks like a brown recluse in the first picture. My uncle has been bitten twice and after seeing the scars that remain I wouldn't mess around with them.


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[mooniac15u]

Looks like a Yellow Sac Spider to me.  They are drawn to the smell of petroleum products so it wouldn't be surprising to find one near the fuel tank.

[mooniac15u]

With respect to the corrosion question, the second picture just looks like peeling paint.  It's harder to see what's going on in the first picture.

[carusoam]

The paint flaking off is not a good sign.

that is a bring it to an expert to see what is going on kind of thing.

there are two types of corrosion.  Surface vs. intergranular.

There are limits to the allowable depth of the corrosion. The limits are pretty small and hard to measure.

If something needs to be replaced it can get expensive.  Sheet metal is a little less than structural (thick) aluminum pieces.

That is probably a proceed with caution kind of thing...?

Spider, thought that was a clean spot!  Some soap and water might give a better view of what is going on in there?

Best regards,

-a-

Edited April 12, 2017 by carusoam

[flyer7324]

A J model I'm looking at as a purchase candidate has lived the last twenty years in the desert southwest.   The airframe generally looks very good, but I did find these spots that I'm not too sure about.   The first pic was taken through the inspection plate at the wing root just in front of the flap on the left wing.   The second is the spar from inside the wheel well.     I tend to think that neither of these is horrible although I do want the stuff in the wheel well looked at better, but I wanted to run it past the experts here and see if I'm missing anything or just to partake in the wisdom of MS.
Note:  the top pic got turned upside-down somehow.
 
 
 

The first pic shows a definite problem since the corrosion is clearly eating away at the spar. The second pic shows surface corrosion which can probably be scotchbrited off and treated.


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[Yetti]

I don't think the crack line running down the  angle at the bottom of the wheel wheel should be there(second pic).  There is fuel on the other side where the surface corrosion is.   Too much could be hiding.  

You should also pull the panel at the back wing along the wing root and look in there.

[EricJ]

2 hours ago, Yetti said:

I don't think the crack line running down the  angle at the bottom of the wheel wheel should be there(second pic).  There is fuel on the other side where the surface corrosion is.   Too much could be hiding.  

You should also pull the panel at the back wing along the wing root and look in there.

I'm not sure what crack you're referring to?

Also, the first pic was taken in the panel under the wing root if that's what you meant.

FWIW, all of the ferrous pieces and fasteners look good.   The fasteners in the same inspection area at the wing root that hold the back of the cage to the rear spar look very good.   No appreciable rust at all.   Compared to some airplanes I've looked at this one is especially clean for its age other than the areas in the pics (that I've been able to find, anyway).

 

[aviatoreb]

From the little I can see in that first picture - it appears as if it might be inter granular corrosion - please have it checked carefully by a mooney expert - if that is what it is - then it is exceedingly expensive and difficult so that would make the plane an absolute no go to purchase - IF that is what it is.

Edited April 13, 2017 by aviatoreb

[Yetti]

[Yetti]

What did under the rear seat look like?  FYI both pictures are upside down.  The brake line goes along the top of the wheel well.

[Yetti]

never mind the 100LL statement.  There is the flap behind that panel.  Too much time upside down looking up.  The rock guards on the wheels are pain to put back on.

[carusoam]

What is the water line looking stain?

Nice work yeti.  I was looking at the pictures again thinking it would be nice to write some circles on them...  then I went down the page....and there they were!

Best regards,

-a-

[75_M20F]

Was this plane kept outside on a tiedown or in a hangar? 

I am guessing outside from the looks of those pictures.

 

[MB65E]

I'd pass and find a cleaner airframe. 

-Matt

[Shadrach]

No one can say anything definitive about corrosion in these photos. It looks like someone did a lousy job of painting the wheel well with a spray bomb. There could be corrosion there, but until all the poorly prepped paint is removed no one will know. I can't see anything that can definitively be called intergranular corrosion. There is no bulging, flaking or any type of exfoliation that I can see. There may be evidence of filiform corrosion but again this could be old and poorly prepped paint.  What looks like water staining does not necessarily indicate submersion, wheel wells get wet and water lays in corners.

Bottom line is that further investigation is needed to determine the existence of corrosion. 

However, further investigation is not needed to determine that this does not appear to be a well maintained airframe.

[N6758N]

18 hours ago, carusoam said:

The paint flaking off is not a good sign.

that is a bring it to an expert to see what is going on kind of thing.

there are two types of corrosion.  Surface vs. intergranular.

There are limits to the allowable depth of the corrosion. The limits are pretty small and hard to measure.

If something needs to be replaced it can get expensive.  Sheet metal is a little less than structural (thick) aluminum pieces.

That is probably a proceed with caution kind of thing...?

Spider, thought that was a clean spot!  Some soap and water might give a better view of what is going on in there?

Best regards,

-a-

There are far more than two types of corrosion Anthony. 

Surface Corrosion

Intergranular 

Dissimilar metal

Filiform

Fretting

Stress corrosion....

The pictures look questionable however as stated above it is hard to tell from the pictures, the areas in question need to be cleaned before you will be able to tell if it is truly corrosion or just some bad paint work...

 

[EricJ]

15 hours ago, Mooney_Mike said:

Was this plane kept outside on a tiedown or in a hangar? 

I am guessing outside from the looks of those pictures.

 

Yes, it's been outside for most of the last twenty years, but in the desert (Nevada).   There isn't any paint bubbling or cracked anywhere else that I noticed, and the color change where the paint is peeling is evidently where the last paint job (in the 1990s) just didn't reach.  So that spot may have been like that for a long time, which I suspect is the case.   The paint is oxidized and looks like it has at least one good polish left in it without going through it completely.

 

16 hours ago, Yetti said:

What did under the rear seat look like?  FYI both pictures are upside down.  The brake line goes along the top of the wheel well.

Haven't popped the seat yet, but will as part of the PPI.   These are pics I took just getting a look at it myself.   The second pic isn't upside-down, perspective pic attached here.   I *think* the crack you highlighted is just a seam.

And, FWIW, this is an ugly airplane but it has promise, and the issues I'm showing here are really the only significant airframe issues I could find that weren't just stuff needing to be cleaned up or updated.  Compared to some other Mooneys I've looked at, this airframe is actually in the best shape so far, sadly, and that's looking at airplanes in the plains and southwest.   I want to make certain of the nature of the issues on this rear spar and see whether it's surface corrosion or intergranular, but that may require a deeper inspection than we can get here.   I wouldn't be surprised if it's been like this for decades, as corrosion is just not an issue in the environment that it's in.   It's dirty, the paint is crap, the panel needs a lot of upgrades, but other than the questions with this spar it seems pretty solid.  It's just coming out of annual inspection and a check flight has been agreed to but not scheduled.   

Edit:  And just to clarify, this airplane spent a decade or two early in its life in the Pennsylvania/Maryland area.  The observed corrosion may have been static since then.   Hard to say.

Edited April 13, 2017 by EricJ

[gsxrpilot]

There is definitely corrosion on that spar cap. I'm going through spar cap corrosion issues with my Mooney right now. The only question is what type of corrosion is it. If it's passed the annual and been declared airworthy without that corrosion being cleaned and treated, I'd say the entire annual is suspect. 

If cleaning the corrosion off the spar cap removes any material, in other words unless it's just filiform surface corrosion, it will cost more to fix then the plane will ever be worth, even in pristine condition. 

Who's doing the PPI? And do they know what they're doing? There are a number of other owners on this board with horror stories to tell about PPI's that weren't done correctly and now they're stuck with planes that will cost more to repair than they'll ever be worth.

Don't let yourself get emotional about a plane you don't own. Because once you own it, you'll be stuck with the emotions.

[EricJ]

4 minutes ago, gsxrpilot said:

Don't let yourself get emotional about a plane you don't own. Because once you own it, you'll be stuck with the emotions.

Yup.   Just trying to find out as much as I can on this particular issue on this particular airplane since it's an obvious sensitive area on these.   

[Yetti]

If it is in annual, they should to the tubular frame inspection SB 208 I believe.

Get pictures of the control rods in tail accessed through the battery access panel.

You are on a hunt to prove it is a worthy airframe since it is suspect at this point till proven other wise.

 

[EricJ]

29 minutes ago, Yetti said:

If it is in annual, they should to the tubular frame inspection SB 208 I believe.

Get pictures of the control rods in tail accessed through the battery access panel.

You are on a hunt to prove it is a worthy airframe since it is suspect at this point till proven other wise.

 

FWIW, I ran an endoscope down the front tubes on the left side and they looked excellent. 

[Yetti]

Were the tubes epoxy painted?

[Shadrach]

13 minutes ago, Yetti said:

Were the tubes epoxy painted?

On the inside?  Not likely...