Pre-buy missed that one...

[weirdjim]

I don't know how we got here, but that crack shown is not caused by corrosion.

No, no, no. The OP was talking about corrosion on a carry-through spar on the overhead of an aircraft. It has nothing to do with the tailwheel crack shown here.

Although I do have a question. Never having SEEN a crack like this on a tailwheel casting, can this crack be (a) reliably and/or (b) legally welded?

Jim

 

[455 Bravo Uniform]

Want a prebuy that missed something? Door was always hard to close and would pop open when not latched down, unless slammed hard. But is it unairworthy? In annual now.

 

[timwinters]

Door was always hard to close and would pop open when not latched down, unless slammed hard.

That's not uncommon. The pop open part.

 

[455 Bravo Uniform]

I may be going down a rabbit hole trying to get it fixed. Door skin has 2 dents, pin on doorframe side of limit arm was bent (don’t know actual name), and lower hinge was twisted and pin would not come out.

Wondering how many hours to get everything “normal” (normal for a 40+ year old plane).

I’m worried I should have left well enough alone. Each end of the hinge is $300, for a total of $600. Found both ends for $200 total.

This shyte is spensive.

 

[timwinters]

Each end of the hinge is $300, for a total of $600. Found both ends for $200 total.

This shyte is spensive.

Yeah, I ran into that also. Had a cracked hinge half on the passenger door. But i have a friend who has a grass strip with an old abandoned straight tail 182 jump plane sitting out back. I have permission to scavenge any parts off of it that I please.

And...

No, I'm not telling anyone where it is!!

 

[Tom-D]

No, no, no. The OP was talking about corrosion on a carry-through spar on the overhead of an aircraft. It has nothing to do with the tailwheel crack shown here.

Although I do have a question. Never having SEEN a crack like this on a tailwheel casting, can this crack be (a) reliably and/or (b) legally welded?

Jim

NO.

 

[Fearless Tower]

NO.

Not disagreeing with you at all, but what is the reference that says what can be welded/approval process?

I recall running into a similar issue trying to document a weld repair (on a aileron hinge) that had been done years before I bought my 170 and while the weld was solid and never going to fail, we couldn’t get the FSDO to sign off a 337. Only legal option was to rip out the repaired section and replace with a salvage part.

I do t remember the reference though that said what could and couldn’t be welded.

 

[455 Bravo Uniform]

Yeah, I ran into that also. Had a cracked hinge half on the passenger door. But i have a friend who has a grass strip with an old abandoned straight tail 182 jump plane sitting out back. I have permission to scavenge any parts off of it that I please.

And...

No, I'm not telling anyone where it is!!

I’ve got that plane narrowed down to the Springfield Missouri area.

 

[Tom-D]

Not disagreeing with you at all, but what is the reference that says what can be welded/approval process?

I recall running into a similar issue trying to document a weld repair (on a aileron hinge) that had been done years before I bought my 170 and while the weld was solid and never going to fail, we couldn’t get the FSDO to sign off a 337. Only legal option was to rip out the repaired section and replace with a salvage part.

I do t remember the reference though that said what could and couldn’t be welded.

There are several rules in welding that prevents this from being welded. You first must know the alloy, and Scott is no longer around to tell us.
Then you must know if it was heat treated, and Scott is no longer around to tell us.
There are ways to figure all this out, but the FAA would never approve with out OEM data.
Getting that would be near impossible. just like your hinge.

 

[denverpilot]

That's not uncommon. The pop open part.

Yup. Most Cessna doors if you grab a wingtip and shake up and down vigorously the door will pop open unless the inside arm is thrown and the big pin engaged.

I may be going down a rabbit hole trying to get it fixed. Door skin has 2 dents, pin on doorframe side of limit arm was bent (don’t know actual name), and lower hinge was twisted and pin would not come out.

Wondering how many hours to get everything “normal” (normal for a 40+ year old plane).

I’m worried I should have left well enough alone. Each end of the hinge is $300, for a total of $600. Found both ends for $200 total.

This shyte is spensive.

You’ll spend a bunch of money and then when you get out and lock it up, I can come along and do the above and open it again in seconds. Hahahaha.

(There are special setups where you can latch that latch from the outside through the window and then lock it that are STCed, but there’s no security to Cessna doors if they’re closed and locked the usual way. The airframe has enough leverage and the cabin flexes too much.)

 

[Fearless Tower]

There are several rules in welding that prevents this from being welded. You first must know the alloy, and Scott is no longer around to tell us.
Then you must know if it was heat treated, and Scott is no longer around to tell us.
There are ways to figure all this out, but the FAA would never approve with out OEM data.
Getting that would be near impossible. just like your hinge.

Its likely more trouble than its worth, but in theory, couldn’t you get the production data from ABI who now owns the Type Certificate and produces the new ones?

 

[Tom-D]

Its likely more trouble than its worth, but in theory, couldn’t you get the production data from ABI who now owns the Type Certificate and produces the new ones?

Do you believe it would be in their best interest to give it to you, placing them back into the liability loop.

 

[Dan Thomas]

Don't talk to A&Ps about welding, talk to a GOOD welding shop.

I think I've relayed this here before...

The carb box on my 182 was badly cracked when I bought it in 2004. In 2 or 3 places. I don't recall how much a new one was...but a LOT.

So, I brought it up on a couple of pilots sites, one was CPA, I was active there back in those days. The "experts" went crazy "you can't weld that!!! It'll just crack again in the immediate future because you'll set up stress points. Etc. etc. etc. Yada. Yada. Yada."

I went to the local commercial welding shop. "Sure, we can weld that!"

"What about stresses?"

"We know how to relieve those." (It's been 14 years, I don't remember exactly what he said they do.)

"And you have someone who is good on aluminum?"

"Yep, He practices on beer cans!"

14 years and about 1600 hours later, it's still just fine. IIRC it cost me $50.

There are weldable and non-weldable aluminum alloys. An airplane is made up of an assortment of those alloys, and welding the wrong one can bring grief.

 

[Dan Thomas]

No problem with understanding that, but "great craters" without any exfoliation on the surface ... GREAT craters?

Jim

The Cessna engineers warned us about it. They have more education than I do. But it would look something like this:

That's from https://www.totalmateria.com/page.aspx?ID=CheckArticle&site=ktn&NM=188

The little peak of stuff wipes away and the surface looks OK except for that little hole. That's why the need for eddy current testing.

 

[Fearless Tower]

There are weldable and non-weldable aluminum alloys. An airplane is made up of an assortment of those alloys, and welding the wrong one can bring grief.

Exactly, and that is why it is so hard to get the FSDO to sign off on a 337.

Let’s just say you could find a good welder who could weld the thing to where it might outlast the rest of the airplane, you’d be hard pressed flying under the radar as a ‘minor’ repair. It’s a structural load bearing component. I don’t see how you could classify it as anything other than a Major Repair, which means you have to have a FSDO sign off on the 337. That’s a non-starter.

Owner would be better off money and time wise to buy either a new one from Spruce or GeorgeC’s used one if he wanted to save some money.

 

[Tom-D]

There are weldable and non-weldable aluminum alloys. An airplane is made up of an assortment of those alloys, and welding the wrong one can bring grief.

The OEM won't even tell you if it is aluminum or Mag?

 

[Dan Thomas]

The OEM won't even tell you if it is aluminum or Mag?

Doesn't have to be magnesium to be unweldable. 2024 and 7075 are not weldable. See https://www.thefabricator.com/article/aluminumwelding/weldable-and-unweldable-aluminum-alloys

 

[Sundancer]

Fabricate a new one, or pay someone to? It's legal, but maybe not as cost effective as buying a new one?

 

[Tom-D]

Doesn't have to be magnesium to be unweldable. 2024 and 7075 are not weldable. See https://www.thefabricator.com/article/aluminumwelding/weldable-and-unweldable-aluminum-alloys

My point was, they won't tell you anything.
AC43,13 says the same thing.

The reason, Zinc is the primary alloying ingredient 7075, It will fume out when you try to weld it, leaving a different alloy in the weld area. Then when it is heated and cooled, the two different alloys will expand and contract at different rates, so it will crack, plus different alloy, different strenght.

 

[Tom-D]

Fabricate a new one, or pay someone to? It's legal, but maybe not as cost effective as buying a new one?

The legality of building owner produce parts will be iffy. When new replacement parts are available the FAA will not approve non-certified parts.
Plus, when you have no manufacturer data, how are you going to produce an exact duplicate.

 

[PaulMillner]

The legality of building owner produce parts will be iffy. When new replacement parts are available the FAA will not approve non-certified parts.
Plus, when you have no manufacturer data, how are you going to produce an exact duplicate.

Tom,

You’ve asserted that before, but it’s simply not true... maybe your FSDO? But the AC says nothing about availability... nor is an owner produced part necessarily 337 worthy.

And as you just alluded, it’s not hard anymore to determine metallurgy, etc.

Paul

 

[Tom-D]

Tom,

You’ve asserted that before, but it’s simply not true... maybe your FSDO? But the AC says nothing about availability... nor is an owner produced part necessarily 337 worthy.

And as you just alluded, it’s not hard anymore to determine metallurgy, etc.

Paul

Still, how are you going to prove it is a exact duplicate without OEM data?
Who is dumb enough to take the liability for the part being used. Would you stick your house in that liability loop, for the price of a new part?
When the FAA scrutinize that for any reason, the person who returned that part for service will be in serious trouble for use of a unapproved part.
Simply because you could not prove to their satisfaction it was a duplicate.

 

[Tom-D]

And as you just alluded, it’s not hard anymore to determine metallurgy, etc.
Paul

you'll never do that to the satisfaction of the FAA, the only way I know of is thru the use of a DAR

 

[Fearless Tower]

you'll never do that to the satisfaction of the FAA, the only way I know of is thru the use of a DAR

So, interesting aside: apparently, the seller had an FAA Authorized Repair Station weld it. Owner was fine with that.

That brings up another question: if the weld is done by an FAA approved facility, does it still require a 337 submission to the FAA?

 

[Tom-D]

So, interesting aside: apparently, the seller had an FAA Authorized Repair Station weld it. Owner was fine with that.

That brings up another question: if the weld is done by an FAA approved facility, does it still require a 337 submission to the FAA?

No, when it was approved under a CRS instruction approved by The FAA, it is good to go.
Example, engine cases are welded every day by Devco. I can't weld one because of FAR 43-A

 

[JAWS]

So, interesting aside: apparently, the seller had an FAA Authorized Repair Station weld it. Owner was fine with that.

That brings up another question: if the weld is done by an FAA approved facility, does it still require a 337 submission to the FAA?

More like an 8130 or Form1 to document the repair.

 

[Tom-D]

More like an 8130 or Form1 to document the repair.

TRUE, all repairs completed by a CRS will be issued a 8130-3 form. Just like Divco does to cases. It will not say it was welded, it will say words to the effect it was repaired IAW instruction Number _______.

 

[Sundancer]

Guys, I know someone who had a third party fabricate a battery box, using the junk one as a template - I'm not versed in this, but as he explained it to me, if it is substantially identical to the OEM part, and it's for your airplane (you can't run a cottage industry, selling to others), it's not an issue with the FAA - they'll rely on the A&P's judgement, and it's "legal" - I seem to recall AOPA magazine had an article confirming it, and not just for orphan airplanes.

 

[Tom-D]

Guys, I know someone who had a third party fabricate a battery box, using the junk one as a template - I'm not versed in this, but as he explained it to me, if it is substantially identical to the OEM part, and it's for your airplane (you can't run a cottage industry, selling to others), it's not an issue with the FAA - they'll rely on the A&P's judgement, and it's "legal" - I seem to recall AOPA magazine had an article confirming it, and not just for orphan airplanes.

What's legal isn't always safe, what's safe isn't always legal.
It's just a matter of which noose your A&P wants to stick his head.
Remember we A&Ps are held to a standard, FAR 43.13

43.13 Performance rules (general).
(a) Each person performing maintenance, alteration, or preventive maintenance on an aircraft, engine, propeller, or appliance shall use the methods, techniques, and practices prescribed in the current manufacturer's maintenance manual or Instructions for Continued Airworthiness prepared by its manufacturer, or other methods, techniques, and practices acceptable to the Administrator, except as noted in §43.16. He shall use the tools, equipment, and test apparatus necessary to assure completion of the work in accordance with accepted industry practices. If special equipment or test apparatus is recommended by the manufacturer involved, he must use that equipment or apparatus or its equivalent acceptable to the Administrator.

(b) Each person maintaining or altering, or performing preventive maintenance, shall do that work in such a manner and use materials of such a quality, that the condition of the aircraft, airframe, aircraft engine, propeller, or appliance worked on will be at least equal to its original or properly altered condition (with regard to aerodynamic function, structural strength, resistance to vibration and deterioration, and other qualities affecting airworthiness).

So how are going to show that your method of construction is acceptable to the Administrator

 

[Sundancer]

Clearly, in this case, it was both legal and safe, in the judgement of the folks doing the work, as well as the Administrator, else it would be proscribed, which it obviously isn't in the sections you quoted. Back to the main point, it is acceptable to the FAA for an owner to fabricate parts, or have someone do so based on the owner's direction. The FAA won't accept an owner fabricating and selling parts, which makes sense.

There is an element of common sense - if the battery box is the same size, shape, material, fabricated in essentially the same way (welded, bent, riveted, whatever) and uses the same attachment method, and the A&P agrees, then it's "acceptable".

 

[hindsight2020]

----ng gatekeeper types. They're why we can't have nice things.

 

[kyleb]

Clearly, in this case, it was both legal and safe, in the judgement of the folks doing the work, as well as the Administrator, else it would be proscribed, which it obviously isn't in the sections you quoted. Back to the main point, it is acceptable to the FAA for an owner to fabricate parts, or have someone do so based on the owner's direction. The FAA won't accept an owner fabricating and selling parts, which makes sense.

There is an element of common sense - if the battery box is the same size, shape, material, fabricated in essentially the same way (welded, bent, riveted, whatever) and uses the same attachment method, and the A&P agrees, then it's "acceptable".

I'm waiting in anticipation of the pedantic response to this accurate summation...

 

[JAWS]

Clearly, in this case, it was both legal and safe, in the judgement of the folks doing the work, as well as the Administrator, else it would be proscribed, which it obviously isn't in the sections you quoted. Back to the main point, it is acceptable to the FAA for an owner to fabricate parts, or have someone do so based on the owner's direction. The FAA won't accept an owner fabricating and selling parts, which makes sense.

There is an element of common sense - if the battery box is the same size, shape, material, fabricated in essentially the same way (welded, bent, riveted, whatever) and uses the same attachment method, and the A&P agrees, then it's "acceptable".

Repairing tends to be easier to document, but as long as standards are met, shop made is fine too.

 

[Tom-D]

and the A&P agrees, then it's "acceptable".

There is the key.
Which noose are they willing to put their head in, If your hard earned ratings are at stake, or your house would you get into that liability loop?

Like I've said certification of owner produced parts if "IFFY" if you can get some one take the responsibility for them.

Remember it's not simply what the FAA will except, we must consider what the liability responsibility is.

 

[Tom-D]

Repairing tends to be easier to document, but as long as standards are met, shop made is fine too.

Repairs, different set of rules. certification of parts = FAR 21, repairs = FAR 43

 

[denverpilot]

So how are going to show that your method of construction is acceptable to the Administrator

If the Administrator stops by, hit him over the head with it and call it a “materials hardness test”?

 

[Fearless Tower]

There is the key.
Which noose are they willing to put their head in, If your hard earned ratings are at stake, or your house would you get into that liability loop?

Like I've said certification of owner produced parts if "IFFY" if you can get some one take the responsibility for them.

Remember it's not simply what the FAA will except, we must consider what the liability responsibility is.

That's really the crux of it.

There is risk involved in operating airplanes and when it comes down to a repair or replacement, someone has to ultimately assume the risk if the repair or replacement fails.

That's easier to do with something like a battery box than a structural component. The issue with a Major Repair involving welding is finding someone who is willing to accept the risk. In this case, the seller found a Repair Station that was willing to accept that risk.

 

[hindsight2020]

That's really the crux of it.

In this case, the seller found a Repair Station that was willing to accept that risk.

And thank God they weren't Tom, otherwise nothing would ever get done.

 

[Sundancer]

That's really the crux of it.

There is risk involved in operating airplanes and when it comes down to a repair or replacement, someone has to ultimately assume the risk if the repair or replacement fails.

That's easier to do with something like a battery box than a structural component. The issue with a Major Repair involving welding is finding someone who is willing to accept the risk. In this case, the seller found a Repair Station that was willing to accept that risk.

roger, concur - I might look for someone to fabricate a door hinge, armrest support (saw an A&P do that, actually); probably not a nose strut. In the case of the battery box, the guy took it to a non-aviation metal shop, asked them to duplicate it for him.

 

[PaulMillner]

The resulting corrosion exceeded Cessna's spec limits and was not repairable. Since the plane was sold with a fresh annual, I didn't learn of this until the following year when my local mechanic did a very thorough first annual on the plane.

Hmmm. Given that, how do you know the mouse didn't move in between your prebuy and your 12-month-later annual?

Paul