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Rear oil cooler

krines

MEMBER
Billings
Where does one find the long bolts and sleeves for this install. Checked with Niagra and they dont't have them. Airforms who is making the baffle does not as well.
 
Try Genuine Aircraft Hardware for the bolts (you'll need to measure for your installation). The sleeves I usually make myself, out of hard aluminum tubing or soft steel tubing.

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Speaking of that, does anyone recall the STC # and holder for that mod? There are probably more than one.
 
OK. I'll be the one.

Just why would you need an STC to move the oil cooler? The basic design has not been changed. Still two hoses connected to an air cooled, oil filled, radiator. No valves or other similar components added into the system. What makes this project rise to the level of a major modification? Read FAR 43, appendix A.

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OK. I'll be the one.

Just why would you need an STC to move the oil cooler? The basic design has not been changed. Still two hoses connected to an air cooled, oil filled, radiator. No valves or other similar components added into the system. What makes this project rise to the level of a major modification? Read FAR 43, appendix A.

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It's likely that they classify this as a cowling/cooling system change. This is on the flow chart as something that is a major change.
 
I guess I'm in all sorts of trouble now, lol, cause I'm not seeing it and I'm not changing my ways.

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I guess I'm in all sorts of trouble now, lol, cause I'm not seeing it and I'm not changing my ways.

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My IA told me the same thing AFTER i had purchased the STC.. he looked at me like I was stupid and said why?? In his opinion, it is not required either.
 
I am not a big fan of a rear oil cooler. Makes it a pain in the ass to work on that mag and robs air from #4 cylinder. My plane came with it so I kept it, but would not change unless I had a good reason. DENNY
 
I am not a big fan of a rear oil cooler. Makes it a pain in the ass to work on that mag and robs air from #4 cylinder. My plane came with it so I kept it, but would not change unless I had a good reason. DENNY

I moved mine back during my engine overhaul. If I hadn’t have sold the old cooler hoses and brackets I’d move it back to the front. I had nice and even CHT spreads. Not anymore.


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I have been running the rear mounted one for years. Maybe it's just the way I have it mounted on a homemade sort of plenum, but my cyls all run very close temps.
 
I moved mine back during my engine overhaul. If I hadn’t have sold the old cooler hoses and brackets I’d move it back to the front. I had nice and even CHT spreads. Not anymore.
Install a flat baffle tight against the back of the cylinder extending high with a bent forward lip. This will funnel cool air into the cylinder and also allow cool air to pass over the top into the oil cooler. I also tilted the top of the oil cooler back for an even flow through the cooler.
 
Same style of cooler, just new location.

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All true, but how do you sign off that the cooling in the new location will be as good as the original location? How do you document that part of the "minor" alteration?
I've participated in oil cooling testing where a small scoop was needed in order to keep the temperatures below limits.
 
Same style of cooler, just new location.

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The type certificate is very specific as it gives the Harrison part number and installed in accordance with Piper drawings. To sign the aircraft off as airworthy means that it meets the Type Design. (Required equipment installed) STC is the only thing that allows deviation.
Or field approval.
 
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What do you say about this DGA?

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Read Part 43 Appendix A Paragraph (a)(1)(xii). One could make a point that moving the cooler is a change to the basic design of the oil and/or cooling system. Using the flow chart in AC 43-210A, one could make an argument that it "Could" have an impact on powerplant operation or other factors affecting airworthiness which is also directly from the definition of Major Repair in Part 1. Always remember, it is the INSTALLER that makes the major/minor determination. If one is unsure, document the decision process in the log book if you call it a minor. If called into question by an ASI, you have your defense already made up. If the ASI is insistent, your defense its that you used guidance provided by FAA. Just be honest when answering the questions presented in the flow chart in AC43-210A.
 
Well your Honor

When I move the cooler to the rear baffle, I consider it a minor mod as the oil cooler still works by ram air moving through an oil filled radiator. And with this installation no new/different parts were introduced into the oil cooling circuit, so the oil cooling circuit of the engine has not been altered. Also, as the baffling is not a structural item, fitting the oil cooler to it still does not rise to the level of a major structural modification.

If I'm to be executed for this, I request a firing squad, at dawn, and I want a good Dominican cigar.

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Well your Honor

When I move the cooler to the rear baffle, I consider it a minor mod as the oil cooler still works by ram air moving through an oil filled radiator. And with this installation no new/different parts were introduced into the oil cooling circuit, so the oil cooling circuit of the engine has not been altered. Also, as the baffling is not a structural item, fitting the oil cooler to it still does not rise to the level of a major structural modification.

If I'm to be executed for this, I request a firing squad, at dawn, and I want a good Dominican cigar.

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I didn't say you were wrong. Just provided the data necessary to make a decision. I think way to many alterations are considered Major and with the proper thought process and decision making would actually be Minor. I recall a time when FAA said ALL radio installations needed to be Field Approvals with no justification as to why and everyone just went along. We now have the tools to help make decisions and support those decisions. I really hate it when A&Ps always run to the FSDO and ask if a given alteration is a major or minor. That is one of the primary functions an A&P should be doing without any need to go to FAA.
 
If I'm to be executed for this, I request a firing squad, at dawn, and I want a good Dominican cigar.

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FYI……The Feds are 60 yrs behind and only approve hangings as of now. If you would like to seek firing squad approval, testing will cost approximately 500k and 3yrs. There has been some FAs for the electric chair but word on the street is that they aren’t being issued. Lethal injection is a hot button issue according to the latest circular and a no go.
 
As to KevinJ’s point - there is likely to be a diminished test ‘pilot’ pool. Could halt the process all together!
 
I didn't say you were wrong. Just provided the data necessary to make a decision. I think way to many alterations are considered Major and with the proper thought process and decision making would actually be Minor. I recall a time when FAA said ALL radio installations needed to be Field Approvals with no justification as to why and everyone just went along. We now have the tools to help make decisions and support those decisions. I really hate it when A&Ps always run to the FSDO and ask if a given alteration is a major or minor. That is one of the primary functions an A&P should be doing without any need to go to FAA.

I agree totally with using the discretion given to determine the repair status of an alteration and readily apply it.

In the example discussed thou, please guide us with the proper language to use in the records, giving us the authority to remove or change a “required equipment item” (item 109, TCDS 1A2) having such an explicit description; part number and installation drawings.

Not trying to argue but seeking knowledge. I am not confident that I can make a good case in front of the FAA.
If it wasn’t on the TCDS it would be a different ball game.
 
I agree totally with using the discretion given to determine the repair status of an alteration and readily apply it.

In the example discussed thou, please guide us with the proper language to use in the records, giving us the authority to remove or change a “required equipment item” (item 109, TCDS 1A2) having such an explicit description; part number and installation drawings.

Not trying to argue but seeking knowledge. I am not confident that I can make a good case in front of the FAA.
If it wasn’t on the TCDS it would be a different ball game.

So given the TCDS has the cooler and installation drawing, and it is listed as “Required Equipment”, the removal and substitution of a different cooler at a different location would be a major alteration and require approved data.


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But when was the last time anyone used a 337 to install an aluminum cooler in place of the original brass one? If you take the above logic, then just using a different part number cooler would require a FA or similar documentation.

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