M20C Spar Corrosion - options?

[Piloto]

As per the pictures I would not worry about. Just sand it off, clean it very well with MEK and apply sealant. Do not apply zinchromate or other coating as this will impair sealant adhesion. Look for other parts in the wing and turbular structure.

 

José

[westbrookgolfer]

Jerry would be a source if you need to sell...

you refer to "jerry" can you tell me more about how to reach jerry, thanks

[Alan Fox]

you refer to "jerry" can you tell me more about how to reach jerry, thanks

Jerry Pressley , or Brent Pressley , Brents cell was 423 273 3557......  Its a few years since I've called for something , give him a shout..... He probably will have a wing too if you want to go that route....

[DaV8or]

I'd have to go with Jose on this one. Treat it, seal it and keep flying. This airplane isn't going to fall out of the sky because of this.

[richardheitzman]

Spar cap can be replaced. You can replace the wing. You can part out the plane. You wont know what you need untill you get that aircraft to a MSC that has an understanding of wing / spar corrosion.

 

wings can be replaced and that is a viable option depending on the value of the aircraft. You might be better off selling / scrapping the aircraft and taking that money and investing in a new(er) Mooney. This is not the first time I have heard of tank leaks turning into a condemmed wing. With the slow down in parts from Mooney, you might make a good bit of money from your aircraft as a parts bird.

[carusoam]

To add some numbers to the conversation...

An M20C sold into that market a couple of years ago for just under $20k, near fully run out, worn paint, leaky tanks (water in) and old, needing an annual.

It went to an MSC fully knowing what it had, but not knowing how much it would cost to get what it needed...

Getting it annualed "properly " would take another $20k, engine rebuild and paint and prop and nav and on and on...

It made a nice down payment on a nicer version of the same thing...

Good luck. Hope this helped give you some ideas.

Best regards,

-a-

[Piloto]

just out of curiosity, was the corrosion discovered when they were sealing the tanks?  Is it something that would have been seen when they installed my bladders?

Bladder installation do not require sealant removal. It is very rare to have corrosion on a sealed area exposed to fuel all the time. However it is not uncommon to find corrosion in the bladder compartment. Bladders can trap moisture and promote corrosion on bare metal. It is recommended that the bladder compartment be zinchromated or coated before bladder installation.

 

José 

[westbrookgolfer]

While I wait on word from Mooney on what their determination is on this spar corrosion issue and what to do next:  I have a nice plane with about 450 hr on it (2000TBO) new engine hoses installed in Jan 13' (done during annual) a panel that includes G430 and about 3600 hrTT on this plane..it is a 1963 M20C (converted to a D) serial number 104....anyone know of anyone interested in this for a really good price?  I'm guessing this engine value at about $8K and the G430 about $3500 or so....not to mention the remainder of the plane (other than the spar issue) that is in good shape.  I'll put together a list of exactly what this plane has it in and post.  Anyone with any interest can contact me via email: lfisher@espec.com - thanks again to everyone who commented over the last few days, your help was invaluable.

[westbrookgolfer]

Hello Mooneyspace members, as a new registered member, I'm looking for a little help from more knowledgeable mooney owners about my options in relation to my newly found issue relating to excessive corrosion around the spar.  I've owned my "C" model for about 4-5 years and have relied on a local AP to provide service and keep me out of trouble when it came to catastrophic issues regarding this plane.  After I bought out the FBO owner (and co-owner) of this plane, an inspection was done indicating no non-repairable issues relating to corrosion.  After a slight weep in one of the tanks (which was repaired by my AP about 1 year ago) it was weeping again and had another AP perform the annual AND fix this weep.  When the corrosion was discovered on the spar.  I simply don't have the funds to repair what will amount to nearly full value of the plane in spar/wing repairs.  I guess I can sell parts off the plane but this would amount to basically giving up on flying and I love it too much to do this.  I have a wonderful engine with about 450 hr (2000 TBO) and re-configured the panel and added a G430.  Is it better to just purchase different wings? repair the spar? or just part out and call it a learning experience....anyone know of a place who buys plane for parts?  I appreciate any assistance from this knowledgeable group - thanks.

While I wait on word from Mooney on what their determination is on this spar corrosion issue and what to do next:  I have a nice plane with about 450 hr on it (2000TBO) new engine hoses installed in Jan 13' (done during annual) a panel that includes G430 and about 3600 hrTT on this plane..it is a 1963 M20C (converted to a D) serial number 104....anyone know of anyone interested in this for a really good price?  I'm guessing this engine value at about $8K and the G430 about $3500 or so....not to mention the remainder of the plane (other than the spar issue) that is in good shape.  I'll put together a list of exactly what this plane has it in and post.  Anyone with any interest can contact me via email: lfisher@espec.com - thanks again to everyone who commented over the last few days, your help was invaluable.

[KSMooniac]

Don't give up on it yet!  Also, your GNS-430 will be worth more than $3500, or you could sell it in less than an hour for that price.      If you have a non-AD prop that will be worth a good bit of cash too.  You could likely make more money parting it out vs. selling it whole now, but it will take a lot of patience and effort to do so.  (I'm currently parting a J that I bought for that purpose from salvage)

[M20F-1968]

The wing is 5 hours drive from me.  Let me know if you want to go this route and I will work on it.

 

John Breda

[DaV8or]

it is a 1963 M20C (converted to a D) serial number 104....

 

I'm guessing you mean a D converted to a C. I've never heard of anyone converting a C to a D, but I guess it's possible. Don't give up on your plane yet. That wing isn't going to fold up and break on you.

[sreid]

Sorry to hear about your plane. Hope you can find a way to get it flying again or at least make some use of it and your investment. Steve

[pirate]

Hopefully you will be able to work things out.

If you do part and want to sell your engine let me know.

Good luck

[westbrookgolfer]

thought I would post some pics of my C taken this morning.  Other than the corrosion around the spar and spar cap.  The plane is just coming out of annual where all new hoses were installed and some exhaust clamps.  The engine has only approx 450 hr on it (2000 TBO) and the plane itself is around 3600TT.  Since I'm moving about 1300 miles away in 36 hours, I'm afraid I'm not going to be able to fuss with parting this out..it will be too far away and I travel too much.  I'll listen to what members have to say.

[Mooneycpf]

From one in New Zealand who has replaced both lower spar caps, doublers and centre splice in my 1965 M20C with lower spar cap corrosion.

 

From my obseravations of the two photos posted, there is exfoliation between the skin and the lower face of the spar cap (an angle section of approximately 2 1/2" x 2" and in the main fuel tank the section is about 5/16" thick) . Problem here is there is also corrosion on the upper surface of the horizontal leg riveted to the lower skin that has tracked under the sealant, so there is corrosion on both sides of the leg. Unfortuantely, the cap is a 7075T extrusion which is very strong and hard, but prone to intergranular corrosion which is what we are looking at on the exposed surfaces. This form of corrosion is like cancer - it tracks out of sight under the surface along the grain of the extrusion and grinding it out could involve removal of a lot of metal. Some of will be some considerable distance from what is seen on the surface, but will generally be along the grain (the direction of extrusion). The redeeming feature here is that there is a large cross section of metal in the spar cap, which gives an opportunity to grind deep into the section before reaching the 10% reduction in cross-section limit. It is also fortunate that it is easy to access with the fuel tank covers removed. Anywhere else in the wing would be nightmare due to lack of accessability and having to do the job with mirrors

 

BUT with the exfoliation corrosion on the underside of the cap too, it will be necessary to remove that corrosion entirely and clean up the mating surfaces otherwise the problem will recur. This will require deriveting the tank skin along the length of the skin - cap joint plus a few rivets back along the ribs to allow the skin to be peeled back to provide access to the mating surfaces. The surfaces can then be whiz wheeled with a 3M abrasive disk back to clean metal. It is fortunate that the tank has had the sealant already removed, so that major drama is over. I would suggest when re-riveting this skin back, wet rivet it with PRC 1442 B-2 and this will prevent water ever tracking from the wheel well back into the joint and kicking off the corrosion process all over again. Also this has the advantage that if a leak ever occurs in that joint it can't track to some other point between the skins and that makes finding the leak source easy as there is no route for the leak to track along the joint and make its appearance some distance away form the source. Further advantage is that PRC has anticorrosive properties too.

 

The job described above is relatively easy to carry out, particularly when the tank sealant has already been removed. Rivet line would require repainting, but that is not a big deal. Deriveting and cleaning out the joint would take about a day and another half day to re-rivet.

 

If the corrosion is deep enough to cause more than 10% of the section to be removed, then we are talking a totally different ball game and is the route I had to follow due to intergranular (dissimilar metals) corrosion between both (left and right) 4130 steel reinforcing plates where the lower fuselage longerons bolt to the lower spar caps. Cause was attributed to the situation related in one of the earlier contributions where the carpet had been wet some time back in history, combined with a high atmospheric salt content we have in NZ due to the proximity to coastlines and big seas producing a lot of salt air. If the a/c has been operated in coastal loctions, it would also pay to have look directly behind the stall switch too as air is forced through the gap in the switch and salt tends to accumulate on the spar face and if condensation occurs it tracks downward to sit between the lower wing skin and the 1" x 1" x 1/8" angle outer spar cap and produces the same exfoliation seen in the photos.

 

For the record, it has taken me five years of working virtually every weekend to replace the caps along with the making from scratch two outer skins on the left wing that had been damaged and repaired early in the aircraft's life. Material costs haven't been great - guessing at around 15k$, but labour doesn't bear thinking about and if doing it again I would seriosly look at finding a second hand wing that is in good condition. If one is available at around 8 k$ I wouldn't even think about replacing the spar cap. Replacement route is full of traps for the unwary as the wing was never designed to have the caps replaced. Drilling of some holes and driving some rivets and Huck bolts can be nigh on impossible as when the wing was originally built the cap was the first item to be attached to the spar web and there was'nt things like skins and ribs installed to get in the way of rivet and Huck guns. Removal of the wing is reasonably easy and couple of guys should be able to do it in about 3 days or less. Mine has root fairlings and removing them took longer than any other job as the rivets had been faired over with filler and there was a mission involved finding them to drill out without damaging the GRP fairing. I also removed the engine to reduce the weight to be lifted when removing the fuselage.

[carusoam]

Interesting and informative first post!

Welcome aboard CPF!

Best regards,

-a-

[Alan Fox]

I believe that I have the last word on this one............Study pic.....

[Sabremech]

Sad end to a Mooney! Hopefully, none of it ends up as beer cans!

[Alan Fox]

Agreed , Chalk that one up to the F.A.A. as they refused a ferry permit....

Sad end to a Mooney! Hopefully, none of it ends up as beer cans!

[sreid]

Agreed , Chalk that one up to the F.A.A. as they refused a ferry permit....

Unbelievable that there was no way to ferry that airplane. Was the corrosion really that bad that it couldn't fly one ferry flight? Hard to believe there was no alternative.

[Awful_Charlie]

I believe that I have the last word on this one............Study pic.....

 

Oh westbrookgolfer - that must be horrible to see :( :(

 

Hope wherever it is you are going brings some sunshine back into your life

[Alan Fox]

Feds actually came out and inspected it , wanted x rays etc.....  Did'nt fit my time restraints ....... Honestly I was probably going to part it anyway , but it would have been a lot less expensive to fly it back in one piece.... 

[westbrookgolfer]

I believe that I have the last word on this one............Study pic.....

Goodbye my baby, thanks for the memories over the last 6 years, I'll never forget!

[KSMooniac]

That is quite a shame!  Are you going to replace her?