M20C Spar Corrosion - options?

[jetdriven]

I remember speaking to Bill Wheat about this at one of the MAPA Homecomings. He said that the wing loading is done as part of certification with a test jig to determine the wing loading in Gs before the wing snaps. He said that the jig broke before the wing did.

At 12 or 14 G's. 

[Alan Fox]

At 12 or 14 G's. 

There is no way in hell that a Mooney wing will survive 12 Gs.....Where do you guys come up with this stuff??? 

[Alan Fox]

Has anyone heard of Mooney wings breaking in flight? Is there any "typical" place that corrosion will show up first?

Corrosion is common on the lower splice plate where the two wing halves meet at their lowest point...Also at the lower spar cap in the wheel wells and in the tanks under the sealant....

[Marauder]

There is no way in hell that a Mooney wing will survive 12 Gs.....Where do you guys come up with this stuff??? 

From the guy who was there for the certification process...

[KSMooniac]

My thoughts exactly...

[Marauder]

It is a shame...

[Marauder]

It is a shame...

[Marauder]

I'm stuttering again I see...

[N601RX]

They could remove the 201 windshield mod and sell it for the $999 they wanted for the entire section.

[DaV8or]

This is the future of nearly all our Mooneys. The first repair required that exceeds the very, very low value of the functional plane and the owner with out the resources, or sentimental attachment, means it is just so much scrap metal. Welcome to GA circa 2013 and beyond...

 

It's getting bad out there folks. Fly 'em if you got 'em.

[Heloman]

Well, airplanes are more and more just reflecting the value of their engines.(Old) King Airs', being that they're on the extreme end of the spectrum for "regular" people to own, have had their values drop to often times less than the sum of their engines, that's what happens when there's no demand for a particular air frame. This is what's happening to most GA aircraft, light twins first; it costs money to take them apart and sit on the parts. The people I know think I'm out of my mind (or a closet millionaire) to fly airplanes.

[carusoam]

Watch the price of fuel...

Rumor has it, that it is going lower, as the oil sands in Canada and the shale oils accross the US are starting to flow.

Employment has been on a steady incline.

Stock market is at an all time high. With no expectation of falling off a cliff.

Home prices have stabilized. Some have even gone up in value.

The dollar has increased in value over other currencies (sorry Euro holders).

Ovation engines cost about $35-45k installed. The price of Ovations are not in decline since 2008. I don't think I can buy one at the price of the engine.

Mooneys are not going any lower in price unless you wear it out...I know the one I want hasn't come down

The Gulf expenses are in significant decline.

Interest rates are low, low, low...

Price of gold is in decline. A sign that the end of the world is not nigh.

All is good for the Mooney pilot...at least, much better than it was 4 years ago...

At least it can be scrapped at the price of aluminum. Fabric planes don't get that honor!

Planes that are out of currency get discounted. Fly often.

Or am I missing something?

Too much sunshine?

Best regards,

-a-

[Urs_Wildermuth]

Fuel price... it now reaches over $12 an USG here in Europe, has for a while. There are politicians who are talking it should be up to $60 an USG to finally stop the wicked people from driving cars, let alone airplanes, and btw they also wish to tax the airlines to death.

 

In Europe, the price of airframes is imploding. I have seen absolutely stunning sales recently, such as a 201 with a brand new engine and prop as well as fully IFR including a KFC 200 e.t.c. for less than $ 40k. There is an "F" around, new paint, new engine and prop and it's been reasonably priced for 6 years but no takers.

 

Come to the effect that following EASA's attack on FAA licenses, a lot of people are loosing their right to fly in Europe, which dumps prices of airplanes even more. I am seeing a LOT of airframes sitting around with engines at TBO, which run perfectly but due to the restrictive policies of EASA and the countries are grounded... what they can achieve with new engines will not be achievable in a sale!

 

We see EU countries going bankrupt with people loosing their savings as even the banks are  no longer safe. The European central bank has declared it a policy to dig into private accounts of people to "save" banks or countries from bankruptcy... with horrifying results.

 

Frankly, I do not see any future for General Aviation in Europe in the long term. Whoever buys a plane now has to know that he will sooner or later loose the total value if he can't manage to sell it outside Europe before the curtain comes down here. The EU is on a straight road into a socialist abyss from which it won't recover in our lifetime.

 

That said, I will do my damnest to get as much flying done before it becomes impossible and am planning for the time after that... there is still hope that a split in the Union may occurr and some countries may recover independance from Brussels.

 

For the rest, I take it with the line out of the famous song out of "Les Miserables", which is more and more true for most EU citizens:

 

But the tigers come at night
With their voices soft as thunder
As they tear your hope apart
As they turn your dream to shame
 

...

I had a dream my life would be
So different from this hell I'm living

 

Well, there sure are tigers in Europe.... EASA is full of them and the politicians are not any better, just the opposite.

 

So much the more I do hope that at least in the US AOPA and whoever else is still fighting for the future of GA may succeed and keep the dream alive.

[jetdriven]

That is really depressing.

[rdv]

Another one bites the dust...

Inter-granular corrosion of the wing spar cap of my '67F. This isn't fun anymore!

[tony]

I'm sorry, I know that maintenance can be discouraging ....what's Inter-granular corrosion?

[DaV8or]

I'm sorry, I know that maintenance can be discouraging ....what's Inter-granular corrosion?

 

It's very often the death toll for vintage Mooneys. It's that white, chalky, flaky crust that forms on corroding aluminum. This repair could easily be more than selling the plane for parts and buying another plane. There are good wings out there to use as a replacement, but the amount of labor involved is extensive, so labor costs are often huge. It takes about 8 hours to take a wing off, but about 80 to put it back on, or so I'm told.

[carusoam]

Inter granular...

That would be the technical description that covers the type of corrosion that is disastrous to a piece of metal. The corrosion leads deep into the structure and can initiate a crack. In other words the strength of the piece of metal is at risk...

Surface corrosion is the other type.

How did I do? This is a 25 yr old memory from engineering school. It may not be exact, but it should get you close...

Best regards,

-a-

[tony]

_{What can or should I do to prevent it from happening to me?  Use that corrosion X stuff?}

[carusoam]

Depending on the surface, paint is a good way to start. Aluminum used to get alodyne primer. This is the greenish or yellowish paint.

There may be an updated version ( i am no expert )...

Clean, paint, then coat, keep dry, then don't spill soda on it...

CorrosionX is good on out of the way surfaces (tail cone, wing interior). It is a little waxy/sticky to the touch...

If you see bare metal because the paint has worn off...consider getting help for it.

This is a non-expert opinion, based on previous experience....

Best regards,

-a-

[DaV8or]

Funny thing about all this wing spar corrosion issue is that it's all academic. To my knowledge, there has never, ever been a wing spar failure in all of Mooney's history that lead to a crash. No one has ever died in a Mooney because of a wing spar failure. Some would argue that Mooney wing spar is almost over built. Yet, a little bit of flaky powder on the surface of one piece and the whole plane is toast.

 

I wish there could be a little common sense and perspective in GA sometimes.

[Alan Fox]

Flaky powder wont condemn a wing , pits in a spar will.....Thats academic...

[DaV8or]

Flaky powder wont condemn a wing , pits in a spar will.....Thats academic...

 

OK, whichever, those pits won't cause the wing to fail either. I'll bet there's a Mooney somewhere in the African bush flying around happily with holes rotted right through the plane.

 

The issue is this, the Feds set the limits on how much structural metal can be corroded in a general sense. No consideration is given to the actual location of the damage, or the way the structure is built. Have you seen the Mooney spar? It's like a Dagwood sandwich of aluminum. A little pitting on the spar cap isn't going to do anything to the strength of the overall spar. I wish we could operate our airframes on condition like we can do our engines.

 

However, I can recognize that it's all a matter of CYA academics and potential liability. The Feds have to draw a line somewhere I guess. Maybe we could take on responsibility and register our "damaged" planes as Experimental?

[KSMooniac]

Actually, the feds don't set such limits... it is up to the manufacturer to choose allowable damage limits and back it up with analysis to prove it safe to operate with XX amount of damage at YY location.  It is a tremendously large task to do so, and I bet it hasn't been done for every possible scenario in a Mooney airframe.  It is theoretically possible to get an approval to operate with some corrosion, but it would require a lot of inspection and structural analysis to get it approved... which would likely cost more than fixing the problem unfortunately.

 

The bigger problem is assessing the condition of the parts of the spar that aren't readily visible...

[Alan Fox]

OK, whichever, those pits won't cause the wing to fail either. I'll bet there's a Mooney somewhere in the African bush flying around happily with holes rotted right through the plane.

 

The issue is this, the Feds set the limits on how much structural metal can be corroded in a general sense. No consideration is given to the actual location of the damage, or the way the structure is built. Have you seen the Mooney spar? It's like a Dagwood sandwich of aluminum. A little pitting on the spar cap isn't going to do anything to the strength of the overall spar. I wish we could operate our airframes on condition like we can do our engines.

 

However, I can recognize that it's all a matter of CYA academics and potential liability. The Feds have to draw a line somewhere I guess. Maybe we could take on responsibility and register our "damaged" planes as Experimental?

Under normal use maybe not , but load up the wing and EVERY component of the wing is stressed , and corrosion on a spar cap will cause a failure , its just a matter of how much and when....