337 Challenges

I recently talked to my AI about submitting a 337 to install 8.50 tires on my Cessna 140. I provided a copy of a previously approved 337 (found in the 120/140 association archives) under the impression it would make my application "almost" automatic. My AI replied that a few years ago the FAA told FSDO's anyone approving a 337 would be personally responsible/liable for the approval and, as a result, (at least the Scottsdale, AZ) the FSDO was not approving any 337 applications. Has anyone else heard this? Are 337's being processed by other FSDOs? If other FSDOs are approving 337s, am I allowed to submit an application to a FSDO in another state?

Thanks,
Dave

That does not sound right. But there is a paperwork package that must go with applications now. Just referencing an older 337 approval is not enough. Off the top of my head you will need to write up the weight and balance change, write up a regulatory checklist that identifies all of the applicable aircraft certification paragraphs and how you address them to maintain the certification of your ship, and Instructions For Continuing Airworthiness. If your mechanic does this he or she has to charge for the time and most owners don't want to pay for the surprising number of hours it takes so they find a way to decline.

The info for you to learn to do all this is out there if you want to take the time. Start with FAA 8300 Major Repair Alteration Job Aid for the FAA inspectors, and 8300-16 Major Repair and Alteration Data Approval. Then FAA 43-210 Standardized Procedures for Obtaining Approval of Data Used in the Performance of Major Repairs and Alterations. Appendix A and B of this last doc will be relevant.

If your mechanic has a sense of humor you can learn to do the paperwork. It is not hard, you just have to know how to do the inspector's job and provide all of the info needed to answer the FAA questions. I've done it. You can too. Be patient and persistent.

Oh, you can relocate your airplane into another FSDO's district but you pretty much have to use the FSDO that covers the location where your airplane or you are based.

Best of luck,

Wes

If you have approved data you can avoid the FSDO approval. It used to be that any prior 337 could be used as approved data but there is now a cutoff date. I don't recall the date. You can also go to a DER (Designated Engineering Representative) with the appropriate authority to provide the approval. Of course that will cost some money. If you can reference approved data on the 337, your IA can sign off the install and just send the 337 direct to OKC. A DER I know of via my Taylorcraft is Terry Bowden, Consultant DER (faa-der.blogspot.com)

My reading of the FAA guidance is that old 337's are now accepted data but not approved data. Yes? No? Makes a difference in the world of the FAA. I have done Field Approvals with the local FSDO and then STC's with the regional Aircraft Certification Office.

As noted above, you either pay by putting in your own time, or pay the labor rate for an experienced/accredited individual. An approval, with a little back and forth with the FAA or a designee, is easily 20 hours of labor at the shop rate. This typically involves some drawings as well as the other paperwork referenced in post #2.

Best of luck,

Wes

It also very much depends on what the 337 is for. Powerplant alterations/changes, for example, are very sticky to get regardless of what you have for approved data.

337's are also subject to what training the FSDO ASI has. To approve a Field Approval my understanding is that the ASI must have completed training at Oklahoma City. With retirements you might find that your local FSDO does not have a trained ASI for that. I think that I ran into that once where a relatively simple application took 10 months when it should have taken two. And some FSDO's put very low priority on Field Approvals. And I understand that covid has frozen FAA training for the time being.

I have started going direct to the Aircraft Certification Office. Their engineers are much more knowledgeable, are helpful, and seem to find GA projects entertaining vs the complex transport category work. Different paperwork, and you wind up with a one airplane STC (or a multiple if you do more paperwork). For me it takes the same amount of time to workj with the ACO as with the FSDO if you can justify that your project qualifies. According to the FAA 8300.16 job aid you likely can argue that putting the larger wheels, tires, and brakes qualifies for processing by the ACO. Just remember to bring all of the paperwork that they need. Treat it as a challenge and a learning experience.

Best of luck,

Wes