Welding

[JAWS]

Is an A&P within his legal authority to weld a engine cylinder.

To answer the original question. No.

Why?

Quote from AC 33-6
1. PURPOSE.This advisory circular (AC) provides guidance to demonstrate compliance with the requirements of Title 14, Code of Federal Regulations (14 CFR) part 33, Airworthiness Standards: Aircraft Engines.

a. It addresses development of weld repairs which are not contained in the engine manufacturer's "Instructions for Continued Airworthiness" (Maintenance Manual). It provides guidance to clarify the areas which should be addressed by an applicant's repair procedure, and/or substantiating data when seeking an approval for weld repair of aluminum crankcases or cylinders of piston engines.

b. This advisory circular also includes information on critical areas of welding, qualifications of welder's, inspection techniques, the thermal processes, and technical data required. This advisory circular references industry and military specifications which are acceptable for use by repair stations as approved data.

This would be enough for me.

 

[Tom-D]

To answer the original question. No.

Why?

I disagree, this AC deals with how to comply with FAR 33, Not with IF a cylinder is or is not a structural part.
This AC is directed at gaining authority and to write methods for compliance with FAR 33
Plus read FAR 43-A it does not add cylinders to the major repair list.

 

[Tom-D]

This would be enough for me.

Oh Well, It is easy to say no, It's not so easy to tell a customer to throw away a cylinder they can never replace.
Specially when you can't prove the repair is not allowed.
I am awaiting the answer from my PMI. I believe they will include this repair in the minor maintenance catagory. After all you can replace a valve guid as a minor thing, why not a small portion of a fin.

 

[Tarheelpilot]

Oh Well, It is easy to say no, It's not so easy to tell a customer to throw away a cylinder they can never replace.
Specially when you can't prove the repair is not allowed.
I am awaiting the answer from my PMI. I believe they will include this repair in the minor maintenance catagory. After all you can replace a valve guid as a minor thing, why not a small portion of a fin.

Let us know what the inspector says.

 

[Tom-D]

Let us know what the inspector says.

Yep, but keep in mind I'm not their top priority.

 

[Tarheelpilot]

Yep, but keep in mind I'm not their top priority.

As long as you haven’t hurt their feelings you’ll get an answer one day. Perhaps

 

[Checkout_my_Six]

then there are times when you want to know "what" is acceptable to the administrator....and have to ask.

 

[JAWS]

After all you can replace a valve guid as a minor thing, why not a small portion of a fin.

Very different processes.

 

[Bell206]

I believe they will include this repair in the minor maintenance catagory.

I must have missed the part this post was not a test question but an actual show and tell.

Was reading article on SIK R-4 (Warner powered) which led to here: http://www.russellw.com/manuals/warner/default.htm . Looking in Section X, 15(2)(c) it states: Repair fins on head by profiling. If fins are broken to root of fin the cylinder and head assembly should be replaced.

Even though this is a Super, they do allow reworking the fins. But looking back to defining what is structural on the cylinder, I seriously doubt any OEM (to include PW) would allow missing pieces or mechanical grinding on any cylinder structure. So maybe the structure is just the barrel and head and not the fins?

Even the AC stated in the “Background” portion that repairs were being performed but now that the FAA was aware of several accidents caused by weld repairs and they had to do something. But as you noted they didn’t add cylinder to 43 App A or even issue an AD. Just left that determination to the A&P with the AC as optional guidance?

Now what if repair of cylinder cooling fins were a practical test skill required for a P cert? The document doesn’t define repair but combined with the above would make a credible point the fins are not structural. Section P(2)(P5): http://www.faa.gov/training_testing/testing/test_standards/media/amp_pts_28a.pdf

 

[Tom-D]

Was reading article on SIK R-4 (Warner powered) which led to here: http://www.russellw.com/manuals/warner/default.htm . Looking in Section X, 15(2)(c) it states: Repair fins on head by profiling. If fins are broken to root of fin the cylinder and head assembly should be replaced.

Even though this is a Super, they do allow reworking the fins. But looking back to defining what is structural on the cylinder, I seriously doubt any OEM (to include PW) would allow missing pieces or mechanical grinding on any cylinder structure. So maybe the structure is just the barrel and head and not the fins?

That's a good find. Thanks pretty much gives me the reference I needed. Wish I had kept my Warner overhaul manuals.

 

[Tom-D]

Very different processes.

And a much more intrusive one.

 

[brien23]

Here is the AC part that defines the cylinder weld is a major repair. It references the old 8300.10 in the beginning but I believe the text from 8900 above is the same.

3. RELATED READING MATERIAL.

a. Directive. FAA Order 8300.10, Airworthiness Inspector's Handbook (11/88).

(1) Volume 2, Chapter 1 describes requirements for approved data; and

(2) Volume 4, Chapter 7 specifically addresses repairs on reciprocating engines and lists welding of crankcases as major repair. (This advisory circular defines as major repair, any weld repair done on a crankcase or cylinder).


From this context I would think the question would be moot. For one, if Junior showed up at your shop with a weld repaired cylinder and his 337 didn't have Block 3 stamped and signed, or if he didn't have a signed 8110-3 approving the repair data there would be nothing for you to RTS. Secondly, Junior shouldn't even have gone to your shop. Based on all the circumstantial guidance I believe Junior would have to work at a 145 shop in order to have an approved Process Specification to weld repair the cylinders as it appears only repair stations with a specialized weld rating can do it. Either way nothing for you to sign.


Add the item to your List of Discrepancies for the owner.

You seem to think advisory circular are mandatory they are not only advisory.

 

[Bell206]

You seem to think advisory circular are mandatory they are not only advisory.

Not at all. In the context of the discussion I was trying to find a guidance path to the weld repair. But absent of higher level guidance, ACs can be brought into the fold as acceptable data which can lead to approved data, not that they are mandatory.

 

[Tom-D]

Not at all. In the context of the discussion I was trying to find a guidance path to the weld repair. But absent of higher level guidance, ACs can be brought into the fold as acceptable data which can lead to approved data, not that they are mandatory.

But there is a higher level of guidance, FAR 43-A says they are not included as a major repair.

 

[Tom-D]

To end this:
I'm signing off the annual as airworthy, with this as part of the maintenance preformed. "Repaired cylinders as required".

 

[Checkout_my_Six]

So you are doing the cylinder welding?

 

[JAWS]

This what the FAR actually says.
(2) Powerplant major repairs. Repairs of the following parts of an engine and repairs of the following types, are powerplant major repairs:

(i) Separation or disassembly of a crankcase or crankshaft of a reciprocating engine equipped with an integral supercharger.

(ii) Separation or disassembly of a crankcase or crankshaft of a reciprocating engine equipped with other than spur-type propeller reduction gearing.

(iii) Special repairs to structural engine parts by welding, plating, metalizing, or other methods.

Is a cylinder a structural engine part? I would say so. But it is up to each person to decide.

If a cylinder fails, what happens to the engine as a whole? Would one cylinder failing put an aircraft at risk?

 

[JAWS]

To end this:
I'm signing off the annual as airworthy, with this as part of the maintenance preformed. "Repaired cylinders as required".

I'd love to know the registration.

 

[Tom-D]

I'd love to know the registration.

Now 6 knows why I don't do pictures

 

[JAWS]

Is an A&P within his legal authority to weld a engine cylinder.

This was the original post

To end this:
I'm signing off the annual as airworthy, with this as part of the maintenance preformed. "Repaired cylinders as required".

This is the end result.

An open ended start and open ended end. Seems oddly appropriate!

Good luck, Tom.

 

[bluerooster]

Putting a fin back on a cylinder with a TIG is about as simple as it gets.

With cast aluminum, (or just about any other cast material) it's just a tad more involved than just sewing it back on with a tig.
But not requiring millions of dollars worth of equipment either.

 

[Hank S]

This what the FAR actually says.
(2) Powerplant major repairs. Repairs of the following parts of an engine and repairs of the following types, are powerplant major repairs:

(i) Separation or disassembly of a crankcase or crankshaft of a reciprocating engine equipped with an integral supercharger.

(ii) Separation or disassembly of a crankcase or crankshaft of a reciprocating engine equipped with other than spur-type propeller reduction gearing.

(iii) Special repairs to structural engine parts by welding, plating, metalizing, or other methods.

Is a cylinder a structural engine part? I would say so. But it is up to each person to decide.

If a cylinder fails, what happens to the engine as a whole? Would one cylinder failing put an aircraft at risk?

Lots of things in an airplane can fail and put the aircraft at risk, but many of those things are not structural parts. For example, the skins on my Mooney aren't structural, but they are on Cessnas. Still would hate to have even one small skin depart in flight, especially if it was the inboard wing skin that forms the fuel tank. Or does that make these two skins structural while the rest are aerodynamic and cosmetic only? Sure gets deep in a hurry, don't it?

 

[JAWS]

Lots of things in an airplane can fail and put the aircraft at risk, but many of those things are not structural parts. For example, the skins on my Mooney aren't structural, but they are on Cessnas. Still would hate to have even one small skin depart in flight, especially if it was the inboard wing skin that forms the fuel tank. Or does that make these two skins structural while the rest are aerodynamic and cosmetic only? Sure gets deep in a hurry, don't it?

Yep, relatively simple issues can become problematic.