Exhaust

[3Dreaming]

Great, I am glad for you, when I was doing the C-90 install and an L-2M with an 0-200, my PMI was working a lot with a guy in the ACO, so she said send them to Jerry and if he buys off on it, I'll sign off also, glad I got everything done, cause she moved on and the PMI I have now is not friendly, to put it mildly

Of the 2 PMI's in the FSDO one just went to school to do field approvals, and the other is scheduled to go. The one who is scheduled to go said he wished he could sign it off, because he had no issues with it.

[LostnSpace]

I finally got the field approval for my exhaust. No real problems, but it did take a while. It had to go the ACO. The PMI I was working with is new to the field approval process, and was a little unsure of what needed to be done in this situation.

Great, I am glad for you, when I was doing the C-90 install and an L-2M with an 0-200, my PMI was working a lot with a guy in the ACO, so she said send them to Jerry and if he buys off on it, I'll sign off also, glad I got everything done, cause she moved on and the PMI I have now is not friendly, to put it mildly

[3Dreaming]

I finally got the field approval for my exhaust. No real problems, but it did take a while. It had to go the ACO. The PMI I was working with is new to the field approval process, and was a little unsure of what needed to be done in this situation.

[PA1195]

At least one section of the shroud still has a PMA sticker on from Aero Fabricators. I think the rest of the exhaust is also from there. They do also offer a stainless PMA'd stacks.

Well that's a good start. It seems locally that the FSDO folks are strongly suggesting there be some supporting data or documentation for alterations. That exhaust system is well proven with known warts. I'm actually surprised that someone hasn't done more of the same with Piper products given the age of Taylorcraft exhausts. A DER may be able to cut through the process quicker than the furloughed FAA that will have a backlog when the fog clears. Once that's done others may be able to use the product. For this plane how you avoid excessive additional expenses getting there may be a challenge.

Gary

[3Dreaming]

Maybe some of these in stainless? It'd be nice to have some FAA/PMA approved P/N's available for the process like those listed below.

https://www.aircraftspruce.com/catalog/appages/piperj3exhaust.php

https://www.univair.com/categories/piper/piper-j-3/exhaust-system.html

Gary

At least one section of the shroud still has a PMA sticker on from Aero Fabricators. I think the rest of the exhaust is also from there. They do also offer a stainless PMA'd stacks.

[PA1195]

It has a system similar to this, https://www.wagaero.com/engine-parts...stem-a-65.html
Except it has stainless pipes instead of mild steel.

Maybe some of these in stainless? It'd be nice to have some FAA/PMA approved P/N's available for the process like those listed below.

https://www.aircraftspruce.com/catalog/appages/piperj3exhaust.php

https://www.univair.com/categories/piper/piper-j-3/exhaust-system.html

Gary

[3Dreaming]

What current exhaust P/N's are on the Taylorcraft?

Gary

It has a system similar to this, https://www.wagaero.com/engine-parts...stem-a-65.html
Except it has stainless pipes instead of mild steel.

[Scott]

I want to make sure I have the paperwork in order, so I am not hanging myself out there when I sell it.

I understand. I guess what I was trying to say is that given the climate on field approvals appears to be changing, there may be a better alternative to "piggy-backing" on a prior approval for a different airplane. I believe the AC could get you to a supportable log book entry, but understanding your preference for the field approval, the AC provides a road map for filling out the 337 e.g.:

"Original exhaust replaced with Piper cub exhaust P/N??? approved for installation on A65-8 under Piper type certificate #???.
Minor alteration to lower cowling to accommodate tailpipes and patch original location.
Alteration does not require a change to type design,
Alteration not listed in Taylorcraft Specification number A-696,
however;
No appreciable affect on W&B
No appreciable affect on structural strength
No appreciable affect on performance
No appreciable affect on power plant operations
No appreciable affect on flight characteristics
No appreciable affect on other airworthiness qualities.

Does additional data need to be approved?

You answer yes to the last question and submit the 337 (however I'm not sure what additional data needs to be approved?)

All of the above is consistent with Figures 3-1 and 3-2 of the AC
I kinda wish we had an AC like that in Canada.

[PA1195]

What current exhaust P/N's are on the Taylorcraft?

Gary

[3Dreaming]

Are you changing an exhaust? Or replacing one PMA part for another?
Your not actually making changes to an exhaust which I agree would be a modification requiring some engineering and potentially testing. The exhaust you have is clearly approved for use on the engine so the only real modification is to the cowling. No appreciable change to the key criteria laid out in the AC.

anyway I'm in no position to argue one way or the other, but regardless, using the regulator's own published decision process should eliminate some of the potential push back with a 337 submission if you decide you need to go that route.

I bought a Taylorcraft that needed the engine overhaul and annual inspection to get it back flying. It has Cub exhaust that likely been running on the airplane was restored several years ago. I want to make sure I have the paperwork in order, so I am not hanging myself out there when I sell it.

deleted

[Scott]

Are you changing an exhaust? Or replacing one PMA part for another?
Your not actually making changes to an exhaust which I agree would be a modification requiring some engineering and potentially testing. The exhaust you have is clearly approved for use on the engine so the only real modification is to the cowling. No appreciable change to the key criteria laid out in the AC.

anyway I'm in no position to argue one way or the other, but regardless, using the regulator's own published decision process should eliminate some of the potential push back with a 337 submission if you decide you need to go that route.

[3Dreaming]

Scott, CFR part 43 appendix "A" list changes to the exhaust as a major alteration. That brings me back to needing an approval.

[Scott]

Based on my albeit limited reading, I get the sense that FAA is interested in getting out of the decision business in favour of the oversight (Transport Canada doing the same). From one perspective this is good because you can make decisions based on your reasonable interpretation of the available data and regulations etc. From the other perspective it's not so good as you still have the old-school inspectors that like to control, and then some owners/mechanics prefer to have the regulator make all the decisions (the perception being the regulator then accepts the responsibility).

SO, During our recent discussion on fabric attachment, I came across this relatively recent FAA AC43-210A document that provides a very useful decision tree that takes some of the subjectivity out of the major repair/modification determination process. It uses the word "appreciable" which is a great word to see in a process like this as it does allow for some common sense IMO. It also indicates to me that what was once a shoe-in for requiring a field approval, is not necessarily the same now.

Maybe this helps, maybe not, but given the Piper exhaust is a PMA part, I would be interested in your thoughts after applying the decision tree (first file) to your exhaust question Tom.

[PA1195]

Have you determined what exhaust is installed? "Piper Cub" systems may have varied by aircraft model and engine and AD's may apply.

Edit: Dave's suggestion about involving a DER would be my first choice.

Gary