The Cessna 120-140 Association Forum

I have a 140 in my shop with damage to aft spar tip assy. (auxilary spar) P/N 0423300-4. I would like to make repair but I am having trouble finding approved data for repair. Will I be better off replacing with a serviceable part? What is availability on part like this? Or are there any 337's out there that have a previous approved repair that I could possibly use to make a repair?
Any help or guidance on this situation would be greatly appreciated.
Thanks

If you can find something in AC43.13-1b that:
"a.the user has determined that it is appropriate to the product being repaired;
b.it is directly applicable to the repair being made; and
c.it is not contrary to manufacturer’s data."
"The repair data may also be used as approved data, and the AC chapter, page, and paragraph listed in block 8 of FAA form 337".

Thank You!
I have also found, what I have determined an applicable repair in Ch. 19 of the Cessna 100 series service manual. Which per the Foreword paragraph in the manual states that this may may be used as a guide for maintenance on a 140.
If I perform repair to these specs. will I still be required to obtain a field approval from the FAA?
Thanks!

To the best of my knowledge, the 100 series service manual is not FAA approved data. So, you still need to reconcile the information in the manual with the information in the AC. If you can do that, you can cite the AC as the approved data and the manual as manufacturer's supporting acceptable data. No field approval required. If the information in the manual conflicts with the AC then you'd need further approval.

Ok Thank You! Now I'm going back and forth the the definition of this member P/N 0423300-4. The IPC calls it a spar tip assy. So would it be considered a spar? I believe it is more of a "lateral rib". Any thoughts?
Thanks!

You might have good advice from either Taildragger Aviation in Illinois or David Lowe Aviation Kentucky.

Can you just replace it?

Replacing would be and option, I have yet found a replacement part. The repair I feel would be straight forward and have supplies for repair in my shop.

Brad:

Suggest you read again John C reference to Ac43-13-1B and determine the data outlined therein if it can be correlated to the repair needed as you see it. It doesn't need to be "chapter and verse" per se, only the application of the engineering principles ( material thicknesses, rivet numbers and spacing involved), but still quoting the applicable associated paragraphs from AC.

I'm and old timer and a student of the "system" from the old Manual 18 days to the present - and have "preached" on the situation time-to-time before.
The FAA has progressed over the years and now gives more authority to the A&P/IAs. The reference that John C made in the AC was a Big Step for the FAA. Years past we had to send a 337 for their review, but that was stopped as long as "approved data" was cited, not requiring a field approval, Even there, field approvals, they told their guys to admonish the A&P/IA for seeking field approval for items that are "minor" - as John C points out frequently.

In writing your "approved 337", in the opening paragraph in block 8, (as I have done), suggest you immediately declare that your repair is considered approved based on the appropriate answer to each of he three paragraphs, and cite each paragraph. As an ASI once told me, "make it look good".
Obviously, use drawing, sketches, etc. and on field approvals I have used photos if appropriate.

Obviously, I can't say this "sermon" is directly applicable to your situation, since no photos, etc but I sense that you would be comfortable and experienced in doing the repair. Bottom line, don't hesitate to use the "tools and authority" given. Of course, send directly to OKC - I haven't heard of any getting returned (or critiqued there) . They may be looking for the words 'approved data" or IAW STC, etc.

Will the ushers come forward with the collections plates.

Edd!! Thank You! That helps me refocus! I appreciate the time and effort you (and the others as well) put into that reply... I will be getting to work now !