The International Cessna^® 170 Association

I have never sent a 337 to the FSDO for the purpose of having them approve the data for repairs. I have many times for alterations, never repairs. If manufacturer data is insufficient we have AC 43.13-1B that can be stand-alone data, or supplimental to manufacturer data. The criteria follows and a direct copy/paste from the AC;

This advisory circular (AC) contains methods, techniques, and practices acceptable to the Administrator for the inspection and repair of nonpressurized areas of civil aircraft, only when there are no manufacturer repair or maintenance instructions. This data generally pertains to minor repairs. The repairs identified in this AC may only be used as a basis for FAA approval for major repairs. 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 when:

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.

Tom, I think we could agree that there are many things in the regs and advisory publications that can be interpreted differently, and that a lot of "how things are done" are predicated on "how things have always been done". Of course there is nothing wrong with your method of sending the 337 to FSDO for approval. But what if they don't approve your repair? What then? For alterations via field approval I will get the data approved first. Alterations are black and white, for the most part, and the part that ain't is minor anyway , but I'm curious how it would be possible to get a repair "pre-approved".
Again, I'm not arguing that getting FSDO blessing on the data in block 8 before signing the form is wrong. But wouldn't you, the IA, have more knowledge about the repair and the data? If an A&P can perform the repair, and an IA inspect and return to service, why would it be reasonable to assume that anyone at your local FSDO would need to be involved in that process? The ASI would have to make the same determination as you (see a.b.c. above). Without visually looking at the repair, and having access to and an understanding of the manufacturers data they could not make this determination.

Del, it is very easy to get a 337 approved after they send it back unaproved, you make the corrections the ASI wants, then resubmit. I usually have a talk to my PMI prior to submitting the 337, to see what he will accept.

and the AC 43.13-1b

http://www.faa.gov/regulations_policies ... ntid/99861

notice the 43.13 does not apply to aircraft that have their own supporting documentation, I believe Cessna will still sell you blue prints for their aircraft.

The 100 service manual.
This Cessna publication does not directly support the 170. the first page tells us the modes it applies to, Thus it can only be used as acceptable data to request the procedures in Chapter 19 be used to make major repairs to the 170.

Tom, I'm thinking we have a different method of achieving the same goal; job done right and documented right. I think you and I could sit down and discuss FAR's, AC's and etc. over a beer and have some good laughs.

I'll suggest (and please shoot me down at will as it's all good info from different perspectives) there is no maintenance manual for the 170 nor where there standard repairs, just standard practices.

The beautiful question ;

but I'm curious how it would be possible to get a repair "pre-approved".

When it becomes evident from field reports that a specific defect is repetitive in nature a manufacturer will approve a repair, publish it as a standard repair and revise their structural repair data.

Thus the questions, is it a major repair? Is there a standard practice covering the repair? Is there a standard repair published that can used as approved data?
So as I see it you have a 170 with no standard repairs; an early 100 series aircraft manual with standard repairs; specific early 172 AMM with standard repairs and now present 172 models with a specific SRM; basically with the same machine with somewhat the same info albeit with more info now, in keeping with the times.

By the way the manufacturers generally used submitted field repairs as a basis for their standard repairs; why endure the pain or pay for something when someone else will!

Jim, I don't understand your point. You quoted a part of a statement I made. I do not pay anybody money to repair aircraft. I get paid to do it. When you say "By the way the manufacturers generally used submitted field repairs as a basis for their standard repairs; why endure the pain or pay for something when someone else will!" I know you have seen their "standard repairs". They do not begin to encompass what I do.
I endure much more pain and expense when I use a manufacturer for repair data than I using a DER. I'm not talking about published repair data. Every repair is different. Time in the waiting room for manufacturer tech support is pain and expense to me. I do what I need to get the job done right, and in the most cost and time efficient manner possible. DER's are great

I should qualify my previous statements. I just re-read Jim's post, and noticed he was referring to "defects". I agree, manufacturers will usually have repair data for known defects. My job is repairing damaged aircraft; each one different. Not common defects.

I'm not in anyway making comment on who does what (correct or incorrectly) I'm just musing on the concept of applying 2014 regulatory maintenance principles to a 50's airplane which I believe is folly at best but as we know that's the way the FAA or the MOT want to play it.
As for what becomes a standard repair, I'll suggest in this highly regulated environment the data is closely scrutinized if there's money involved... That's not the case with legacy 100 series aircraft.

This is truly one of the most interesting discussions I have followed on this site. Thank you.

T. C. Downey wrote:

Ron Fenili wrote:My A&P is nearly finished with repairing the outer two ribs on the wings of my 170b. All new parts were used such as ribs and skins. The stringers had to be cut and repaired according to the Cessna 100 series service manual. After reading the CFR's I am reasonably sure that the service manual is approved data. All was done under the eyes of an IA. From my further reading of the CFRs this is a major repair and requires an inspection by the IA before sign-off. Am I correct in my appraisal of the CFR's?

The 100 service manual is not approved data for major repairs, a 337 with the repair described in block 8 and a FAA approval stamp in block 4 would be required.

From FAR 43-A
(b) Major repairs—(1) Airframe major repairs. Repairs to the following parts of an airframe and repairs of the following types, involving the strengthening, reinforcing, splicing, and manufacturing of primary structural members or their replacement, when replacement is by fabrication such as riveting or welding, are airframe major repairs.

(i) Box beams.

(ii) Monocoque or semimonocoque wings or control surfaces.

(iii) Wing stringers or chord members.

The last AI meeting I attended (2013) The Feds said the Cessna service manuals are "Approved Data" /acceptable that means it canin fact be used and includes the repair section. As I reviewed it It mimics the 43.13. Be sure if you are using it to reference the latest revision number.

Mod note: I fixed the quoted portion of this post.

After several hours of discussion with two very helpful local ASI's, what I have learned is that the pre-1962 service Manual for 172's, 180's, etc but not for the 170's can be used as acceptable data since the wing is the same as the wing on the 170b. This applies since the part numbers are the same and so long as the manual is not in conflict with 43.13-1b. In that event the IA can sign of the appropriate 337 describing the work.

Hope this helps. It sure did help me.

Ron

Yes, the pre manual can be used as long as the revisions are up to date. Their friendly PMI's can set your buddies straight on that point.