Look what we found under the window….Corrosion

[EricJ]

When I bought my airplane an IA pointed out that you can send an endoscope down between the window and interior and get a pretty good view of the tubes.   The tubes on the pilot side are the most susceptible, and it's not hard to loosen up the side panels enough to do that.   It isn't strictly necessary to remove the panels to get a good idea of the tube condition during a PPI or other inspection.

[carusoam]

On 2/4/2023 at 11:58 AM, DCarlton said:

Skywagons seems to move a lot of M20s; he's had some nice ones.  I would like to have seen a close up of the tubes that were cut out in that airplane.  

Posts like this convince me over and over again to keep flying the same Mooney I've been flying for 20 years.  Always wondered how hard it would be to convince a seller to let you do a really thorough PPI, to include removing the interior, particularly when the market is hot.  

Skywagons… did a great job of pointing out the issues…

What I didn’t like so much… it sounded like this was a real problem for all Mooneys, all of the time…

 

It has become less of a problem over time… as people got the crummy insulation removed properly…. Via the SB208…

And cared for the planes better by putting a cover on them…. Covers have become a normal thing to do…

And properly sealing the windows that get replaced every few decades…

 

When you see a plane abandoned outside, with no cover on it…. It makes you want to get the best PPI possible…

Unfortunately…. When you are looking at ramp rats for sale… the best possible PPI is most likely out of your price range… or you are a mechanic looking for a project.

If your next Mooney costs as much as your house… you look forward to discussing the results of the PPI with the DMax… as he runs down the list of items they found, and how clean the inside of the plane is…

If your next Mooney has been abandoned… it is not a fun experience… trading the known for the unknowns is never fun…

Buy and hold…. Never made more sense…. 
 

PP thoughts only, I owned nearly the worst M20C available at the time… it was near worn out when I bought it… it was fully worn out when it sold a decade later… the non wear items were in really good condition… 

The only serious corrosion problem I encountered… was a hole that allowed rain water to fill my fuel tanks… hiding next to the fuel cap…  not a real expensive fix either… unless you have a house and kids to feed as a first priority… 

 

Oddly, once you have a really expensive plane… trading laterally for a similarly expensive plane… is a whole lot less risky…

Find Ken, who trades his plane approximately every other year… without performing a PPI… on the plane.  Where PPI of the seller is a good gauge…

 

PP thoughts only, not a plane sales guy…

Best regards,

-a-

 

 

[Bartman]

On 1/28/2023 at 10:46 AM, Mooneymite said:

 

Excellent reason the inspection portion of SB 208B should be completed periodically and certainly as part of every PPI.

You never know until you look.

My J had SB 208B completed several years prior to my purchase in 2007, but there was no corrosion so only the insulation was replaced, and no need for repairs.  In 2016 we replaced coax cables and found some light corrosion on the tubes under the pilot window.  I removed all of the interior and used plastic sheeting to cover everything.  I bought a shop vac with the HEPA filter, ran the hose through the small pilot side window, and bought a couple of grades of Emery Cloth by the roll.  Rig the shop vac so it is directed at the area where you are working and don't work the Emery Cloth too aggressively so that you contain the dust and debris to a small area near the shop vac hose.  Also wear a respirator and use the Dupont Tyvek coveralls.  Don't wear those clothes or shoes home otherwise you contaminate your car and home.  I discarded the Shop Vac when I completed the project.

The original paint is Chromium based and you want to minimize exposure to that stuff.

[carusoam]

Nice details Bartman,

thanks for sharing them…

Best regards,

-a-

[Jim Peace]

On 2/4/2023 at 8:01 AM, M20F said:

Covers and hangers don’t stop corrosion, corrosion-x stops corrosion. 

true...but it helps a lot to have a cover that prevents water from dripping down between the windows and the frame....

[Jim Peace]

Some before and after pictures of mine.  My plane lived outside at the Van Nuys airport for over 40 years....not covered that well.  It's in a hangar now in Florida and covered up very well when on trips.  

[exM20K]

Remember: it’s not just rain and dew intrusion that can get the insulation wet.  Especially for the turbos, a couple hours in the mid to high teens will cold soak the whole airframe pretty well.  If landing in a high dew point environment, stuff will get wet from condensation.  I see it on the bottom of the wing where the cold fuel is just about every time I land in Florida.

-dan