Corrosion.

[Tom-D]

just a few pictures of what I found over the last week while changing seat tracks on Cessna 182

 

[Checkout_my_Six]

so...what.

 

[texasclouds]

So is that enough to make it unairworthy until repaired? What is the repair procedure?

 

[Tom-D]

So is that enough to make it unairworthy until repaired? What is the repair procedure?

It is structure, you allow it to progress, it can become unairworthy.

the track got replaced, the floor was cleaned treated and primed.

FYI. replacing the forward floor in a Cessna 182 is a huge job. involving the door post structure, and the gear box structure. (major repair)

 

[Tom-D]

Anyone notice? the floor was painted prior to me pulling the track?

seeing the corrosion under the track, makes ya wonder why they did that.

 

[Checkout_my_Six]

so....maybe they were fixing other corrosion? No biggie Tom. See this all the time.....

 

[Tom-D]

so....maybe they were fixing other corrosion? No biggie Tom. See this all the time.....

yep.. the Cessna's have a problem in this area. almost every seat track I pull has some corrosion.

 

[Clip4]

yep.. the Cessna's have a problem in this area. almost every seat track I pull has some corrosion.

I have pulled these several times in a 182, never had corrosion under them. Makes me wonder if a water trapped between the rail and a wet floor is the causation.

 

[EppyGA]

Moral of the story, don't live on the coast

 

[mondtster]

Moral of the story, don't live on the coast

Even dry country planes seem to have trouble under the seat rails.

 

[Dan Thomas]

The worst corrosion I found was in a 210. Someone had spilled Coke (pop) in it and didn't clean it up.

People track water and mud into airplanes, too.

Cessna considers those rails to be part of the airplane's structure. They carry tensile loads in the belly and act as stiffeners.

 

[wilkersk]

Tom, do you fay-seal new new seat rails? This seems like a common problem.

 

[JAWS]

Epoxy zinc chromate primer is your friend!

 

[Tom-D]

I have pulled these several times in a 182, never had corrosion under them. Makes me wonder if a water trapped between the rail and a wet floor is the causation.

what years were he 182s.

 

[Tom-D]

A 1964 - 182

 

[Clip4]

what years were he 182s.

1979

 

[Tom-D]

1979

undoubtedly better cared for than many.

 

[Tom-D]

Tom, do you fay-seal new new seat rails? This seems like a common problem.

I do not.

 

[tom28z]

Sent from my iPhone using Tapatalk

 

[Tom-D]

Time for a major repair ?

 

[Clip4]

Now that one is common.

 

[Tom-D]

Now that one is common.

It's common where ever they used that glue.
170s have a problem the same cause on the rear cabin former where Cessna glued the head liner
I've seen a couple with the corrosion where you showed it. referred both to repair facilities.

 

[DutchRoller]

so...what.

Don’t you know?


Everyday mundane stuff is newsworthy in this day and age. Get with the program.

 

[Clip4]

It's common where ever they used that glue.
170s have a problem the same cause on the rear cabin former where Cessna glued the head liner
I've seen a couple with the corrosion where you showed it. referred both to repair facilities.

I meant the location. If I am interpreting the photo correctly it is showing the skin foward of the door where the heat discharge is located. For some reason that seems to be an area that is favorable to corrosion due to condensation.

 

[bluerooster]

just a few pictures of what I found over the last week while changing seat tracks on Cessna 182

That ain't nuttin', here's what I found in my Cherokee:

 

[PaulS]

Those didn't look bad to me, certainly worth cleaning up since you were checking but hardly serious.

 

[Dan Thomas]

That ain't nuttin', here's what I found in my Cherokee:

That's about the worst I've seen. Exfoliation. What did the underlying structure look like?

 

[Dan Thomas]

Those didn't look bad to me, certainly worth cleaning up since you were checking but hardly serious.

You'd be surprised how little it takes to compromise the strength.

 

[Lndwarrior]

Don’t you know?


Everyday mundane stuff is newsworthy in this day and age. Get with the program.

Some of us who are less knowledgeable than some of you actually find this interesting. I will never understand why some feel the need to throw darts at those who actually teach some of us.

It's like some people are so unhappy with their lives that they have to lash out at others for absolutely no reason other than to sound superior.

When it's done for such a "mundane" topic it just comes across as churlish.

Why not just move onto the next post if you have no interest rather, than bringing such negativity?

 

[Dan Thomas]

Some of us who are less knowledgeable than some of you actually find this interesting. I will never understand why some feel the need to throw darts at those who actually teach some of us.

It's like some people are so unhappy with their lives that they have to lash out at others for absolutely no reason other than to sound superior.

When it's done for such a "mundane" topic it just comes across as churlish.

Why not just move onto the next post if you have no interest rather, than bringing such negativity?

Exactly. It's mundane to a lot of owners until the corrosion is found in their airplanes. Then it's not mundane anymore. It's expensive. Topics like this should help educate potential buyers of what to watch out for when looking at ancient airplanes, and most of the fleet is getting pretty ancient. And too many think that because aluminum doesn't rust it should last forever. They've never been mechanics dealing with this stuff. Aluminum, especially copper-alloyed aluminum like the 2024 commonly used in light airplanes and the 7000 series zinc-alloyed stuff used more in heavy aircraft, can corrode at an amazing rate under the right conditions. Adding copper or zinc makes the aluminum much stronger, but like everything in aviation there are compromises, and corrodability is the tradeoff here.

 

[PaulS]

You'd be surprised how little it takes to compromise the strength.

I don't see it there Dan, I just see surface stuff, like someone spilled their coke or fruit juice. No penetration. I do agree that once you start seeing holes or even craters you should become concerned as these can act as stress concentrators.

 

[Tom-D]

Exactly. It's mundane to a lot of owners until the corrosion is found in their airplanes. Then it's not mundane anymore. It's expensive. Topics like this should help educate potential buyers of what to watch out for when looking at ancient airplanes, and most of the fleet is getting pretty ancient. And too many think that because aluminum doesn't rust it should last forever. They've never been mechanics dealing with this stuff. Aluminum, especially copper-alloyed aluminum like the 2024 commonly used in light airplanes and the 7000 series zinc-alloyed stuff used more in heavy aircraft, can corrode at an amazing rate under the right conditions. Adding copper or zinc makes the aluminum much stronger, but like everything in aviation there are compromises, and corrodability is the tradeoff here.

Exactly,, this area is covered in an AD in Cessna singles. This is why it almost mandatory to do the AD check on any aircraft prior to buying.

 

[mondtster]

I don't see it there Dan, I just see surface stuff, like someone spilled their coke or fruit juice. No penetration. I do agree that once you start seeing holes or even craters you should become concerned as these can act as stress concentrators.

You may want to look again. Those Cherokee rails that were posted are the worst I’ve ever seen. That is far beyond surface corrosion, they’re dust.

Even the ones posted by Tom that are the subject of this thread are beyond just surface corrosion and Tom was doing the right thing by treating it.

 

[PaulS]

You may want to look again. Those Cherokee rails that were posted are the worst I’ve ever seen. That is far beyond surface corrosion, they’re dust.

Even the ones posted by Tom that are the subject of this thread are beyond just surface corrosion and Tom was doing the right thing by treating it.

I was responding to the original post.

 

[Dan Thomas]

I was responding to the original post.

The floor skin is thin. Corrosion creates millions of tiny pits that act as stress concentrators. It's not just a nice smooth, level reduction in thickness. And those pits harbor further moisture that accelerates the electrolytic processes involved in corrosion.

Castings like the massive spar carrythroughs found in the Cessna 177 and 210 are subject to corrosion caused by water getting into the roof or condensing in the ceiling as a result of the breathing of the occupants. Cessna gets pretty excited about that corrosion, since it has been found to create voids within the casting that have only a tiny entrance.

 

[Dan Thomas]

See this: https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=2ahUKEwi3qde-yqDgAhVL2IMKHflxB7gQFjABegQICRAC&url=https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_43-4a_.pdf&usg=AOvVaw1ajbHGE1lop_Qch4uBVqhO

Scroll down for pictures.

Even better: https://www.google.com/url?sa=t&rct...itiative.pdf&usg=AOvVaw0zWgTsAGdmB2KmdE1w33-6

 

[bluerooster]

That's about the worst I've seen. Exfoliation. What did the underlying structure look like?

Cleaned right up, and looked good. A nice surprize.

 

[PaulS]

The floor skin is thin. Corrosion creates millions of tiny pits that act as stress concentrators. It's not just a nice smooth, level reduction in thickness. And those pits harbor further moisture that accelerates the electrolytic processes involved in corrosion.

Castings like the massive spar carrythroughs found in the Cessna 177 and 210 are subject to corrosion caused by water getting into the roof or condensing in the ceiling as a result of the breathing of the occupants. Cessna gets pretty excited about that corrosion, since it has been found to create voids within the casting that have only a tiny entrance.

Fortunately I didn't see any of those issues in the original post, in fact it looked as good as new after he cleaned it up. We are talking floor skin and seat rail here with superficial oxidation, not carry through spars with corrosion you depict above.

 

[Dan Thomas]

Fortunately I didn't see any of those issues in the original post, in fact it looked as good as new after he cleaned it up. We are talking floor skin and seat rail here with superficial oxidation, not carry through spars with corrosion you depict above.

We're talking about structural parts, and that floor skin is a structural part. It carries flight loads like almost every other skin in the airplane and is part of the landing gear box's rigidity. The pitting and surface corrosion, if not cleaned up and treated, would continue at an accelerated rate until some other mechanic discovered that the whole floor needed tearing out and replacing. Or something cracked due to flight and landing loads on a badly weakened part.

I know you don't like to believe some of the stuff posted here by experienced people. What is your experience in aircraft maintenance?

 

[Tom-D]

and is part of the landing gear box's rigidity.

Not true..Landing gear boxes are the skin forward of the floor skin.

The floor skin is how ever structure, because it is a part of the fuselage forward box assembly.
each seat rail is attached to a stringer that connects the floor skin to the lower fuselage outer skin, making it a box assembly all the way back to aft of the baggage compartment