The Cessna 120-140 Association Forum

I would like to put the Aero Classic 8.50-6 Tundra Tires on my 140. They are tso'd. Do I need anything else to be "legal"? Yes I read through the last thread and I guess I don't understand how you get a 337 or who would do it.
Any help would be great. Thanks

The 337 is just the form you record the (major) modification on. One of the things you list on the 337 is the means of approval. A major modification requires "approved data" in support of it. The following, and only the following, constitute approved data:
1. Type Certificate Data Sheets
2. Aircraft Specifications
3. Supplemental Type Certificates (STC's) (Note: Persons interested in using an STC must have approval in accordance with 49 U.S.C., section 44704, from the holder of the STC prior to it's use.)
4. Airworthiness Directives (AD's)
5. Manufacturer's FAA Approved Data (DOA)
6. Designated Engineering Representative (DER) Approved Data With FAA Form 8110-3, Statement of Compliance (Note: This type of data usually requires additional approval.)
7. Designated Alteration Station (DAS) Approved Data
8. Appliance Manufacturer's Manuals (Excluding Installation Instructions)

AC 43.13-1, Acceptable Methods, Techniques, and Practices (Aircraft Inspection and Repair), may be used directly as approved data (for repairs only) without further approval only when there is no manufacturer repair or maintenance instructions that address the repair and the user has determined that it is:
• appropriate to the product being repaired;
• directly applicable to the repair being made; and
• not contrary to manufacturer's data.

AC 43.13-2, Acceptable Methods, Techniques, and Practices – Aircraft Alterations may be used as approved data for major alterations when the AC chapter, page, and paragraph are listed in block 8 of FAA Form 337 when the user has determined that it is:
• appropriate to the product being repaired;
• directly applicable to the repair being made; and
• not contrary to manufacturer's data.

FAA FIELD APPROVAL (FAA FORM 337) issued for duplication of identical aircraft may be used as approved data only when the identical alteration is performed on an aircraft of identical make, model, and series by the original modifier. (I recall the form 337 used to have a block you could check if you were applying for multiple approvals, sort of like a personal STC.)

FAA Form 337s approved in 1955 or earlier may be used as approved data.


So, what you need to get is a field approval, unless you can find an approved 337 from 1955 or earlier. Previously approved 337s from 1956 and later can be used as acceptable data in support of a field approval.

The process goes something like this: Your IA writes up the proposed modification and gathers up the acceptable data. Present this packet to to his (or her) local PMI for approval. The PMI fills in block 3 of the 337 and Bob's your uncle.

WOW!
Thanks John. Looks like 600-6 tires it is.

Don't give up so easily! If you can find a previously approved 337 and your IA has a good relationship with his PMI it shouldn't be difficult.

Where would I search for a previously approved 337? Is there a database somewhere?
Thanks

Does anybody have a copy of a previously approved 8.50-6 tire 337 that I could get a copy of?
Thanks

Working on it...

There were a number of 337s on the old site. Maybe we can dig some of them up.

Thank You!

I'd be interested in getting a copy of the 337 as well!

Any chance someone could point me to it?

Thanks
Marshall

I have a copy of one, but I don't know how to show it on this forum. I also don't remember where I got it.

It's a PDF file. If someone can tell me how to put it on here, I'll be glad to do it.

Steve