You can help contribute to the Knowledge Base without writing anything!

It's been very handy to keep some examples of stamped 337 field approvals in our knowledge base for those submitting for follow-ons.

Example here for the Skywagon tires section.

So if you have any juicy ones in your logbooks, you can easily share them with BCP to post in the Knowledge Base under that aircraft's modifications section.

Here's how:

2026 UPDATE: Microsoft retired the Lens app, which sucks. A new replacement has emerged though in PDF Gear. At some point soon I will replace the detailed steps below to showcase the new app. For now, these concepts should be universal to the overall objective.

1. Install Microsoft Lens for iOS or Android (my tutorial is Android):



2. Lay your documents on a dark background like your wife's nice placemats. Hover your phone as normal as possible (camera looking straight down) above the page. Portrait mode is best. Watch the orange outline as it detects the page edges in real time. Move the phone camera slightly until the orange outline envelops the entire page.



3. Hold steady and snap the pic



4. Don't tap the orange checkmark button yet. Tap the "new page" button.



5. Flip your 337 over or to the next page.



6. After you've shot the 2nd page, now you can tap the orange checkmark "Done" button.



7. It's going to ask you what you'd like to name the file and what you want to do with it. Name it something intelligent, then select the checkbox only for PDF. Tap the Save button.



8. Now it's time to send it to old Zane by email. The exact details of this step may vary between iOS and Android, but here's how on the Android version: Click the 3-dot menu on the document thumbnail. A menu pops up below. Choose "Share."





9. It will present you with the various sharing methods. Select your mail app and send to [email protected]

Done!

Obviously there are some privacy issues with sharing a document with your N# and your A&P IA's certificate number on it. To have the document serve as follow-on data, I think we need those numbers to be valid. If you just want to give people text for reference, let me know and I will redact those details before publishing on BCP.

Did this sail over heads? Or are you all thumbing through your logbooks for useful field approvals?

Wait I hear something, disregard its just crickets

Zzz wrote:Did this sail over heads? Or are you all thumbing through your logbooks for useful field approvals?

Would LSTCs help at all Zzz? That's about all us Canafians can really offer, but I do have a few of them available. As well as a couple letters from TC that I've been using as approved data for a couple specific installs.

Maybe I can contribute to the "Canadian file", I'll have a look.

A1Skinner wrote:

Zzz wrote:Did this sail over heads? Or are you all thumbing through your logbooks for useful field approvals?

Would LSTCs help at all Zzz? That's about all us Canafians can really offer, but I do have a few of them available. As well as a couple letters from TC that I've been using as approved data for a couple specific installs.

If you guys have a similar process where example field approvals count as precedent, sure. I was under the impression TC didn't grant FAs?

Zzz wrote:

A1Skinner wrote:

Zzz wrote:Did this sail over heads? Or are you all thumbing through your logbooks for useful field approvals?

Would LSTCs help at all Zzz? That's about all us Canafians can really offer, but I do have a few of them available. As well as a couple letters from TC that I've been using as approved data for a couple specific installs.

If you guys have a similar process where example field approvals count as precedent, sure. I was under the impression TC didn't grant FAs?

Yes that's right, no field approvals. But we have limited supplemental type certificates (LSTC) that are tied to one specific airplane. It helps to provide one if you are trying to get one for another. Anither option is a letter that is from TC granting use of something proven, which makes it approved data and doesn't require a STC. Those are very rare, but they do happen from time to time. I have one specifically referencing a certain propeller installation on a C175 that makes quite a performance difference.

Bump for 2020! Oh wait, am I too early?

The app I’ve been using for stuff like this in iOS is called “Cam Scanner”, and it is slick. Take a pic in the app, and it improves lighting, etc to make a document more readable.

Slick!

MTV

The notes app on any iPhone lets you scan a document with total ease. Literally just point and click and it perfectly crops the scan and finds the edges of the document.

The really valuable 337's are the ones dated 10/1/1955 or earlier. If anyone has any good ones in their aircraft records these are the really good ones to share.

These old 337's can be used directly as approved data for current field approvals.

See FAA AC 43-210, chapter 2, 201(a)(7)

https://www.faa.gov/documentLibrary/med ... 43-210.pdf

2026 UPDATE: Microsoft retired the Lens app, which sucks. A new replacement has emerged though in PDF Gear. At some point soon I will replace the detailed steps in the original post to showcase the new app. For now, these concepts should be universal to the overall objective.

Another user suggested that the default Notes app on iOS will do the same.

Ultimately, the idea is to send your field approval 337s to be hosted in our knowledge base so others can draft follow-on 337s.

I don't understand the request here to upload your field approval 337s - what am I missing? You can look up the 337s for any aircraft by N-number on the FAA CARES website. I've done so a few times for aircraft which had field approvals of interest.

https://cares.faa.gov/home

Christina Young wrote:I don't understand the request here to upload your field approval 337s - what am I missing? You can look up the 337s for any aircraft by N-number on the FAA CARES website. I've done so a few times for aircraft which had field approvals of interest.

https://cares.faa.gov/home

That's a cool resource, I didn't know about it. For our purposes though, the idea is to tie a particular modification to an aircraft type, not knowing the N-number of an aircraft that has it. And there's no authentication wall like there is with the FAA. And FAA web properties are generally painful to use.

So...you want to add a long prop to your Pacer for which no STC exists, but surely someone must have a field approval somewhere for it? You would look up PA-22 here, then find the type of modification you want, then hope that some supporting approval docs are linked.

We're also coming at it from the backcountry/bush flying angle, and focusing on documenting those types of mods.

Canadian LSTC is the same as a field approval in the states. A US field approval helps a lot to obtain a LSTC in Canada and i would suspect the same the other way around. If its been done before its almost a rubber stamp.
We are working on 2 LSTC’s right now
Genius scan is what I use, a free app that works perfect.

I've got an SSTC for the GFC500 on the early C206 models if you'd like me to scan it and send it in Zzz. Already sent it to a fellow in Montana that is trying to use it as a basis for a 337 to get the autopilot installed in his bird. Sounds like he's having a lot more difficulty then I did, which is crazy to me as its usually the other way around.

A1Skinner wrote:I've got an SSTC for the GFC500 on the early C206 models if you'd like me to scan it and send it in Zzz. Already sent it to a fellow in Montana that is trying to use it as a basis for a 337 to get the autopilot installed in his bird. Sounds like he's having a lot more difficulty then I did, which is crazy to me as its usually the other way around.

Anything you think might be of use to other owners of the type, canuck or yank, email it over knowledge@

Bush Buggy wrote: ..... If its been done before its almost a rubber stamp. ......

That might be true in Canada, but not in the US in my experience-- not with the SEA FSDO anyways.

This may be helpful. You do not have to use your local FSDO for your field approvals, any FSDO office can handle field approvals. Its unfortunate that so many FSDO inspectors have retired in the last five years and this continues a fast rate. The new hires are not comfortable/afraid to sign their name on an approval. If you hit a wall, it may be time to find a well seasoned FSDO inspector who will sign off on the approval you are seeking. This is NOT easy and requires research and networking. Flight Standards is well represented including the Regional level inspectors at the Oshkosh airshow in the FAA hangar beside the ATCT. I suggest this a good place to ask your field approval questions.