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[bigrenna]

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[bigrenna]

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[Bruce Fenstermacher]

Greg, it would be no big deal if you were located in a place (Alaska for example) that installed these all the time and was familier with them. The area you are in and the FAA people there makes a big difference what and how things get done. It shouldn't but it does.

A completed 337 for an installation on another airplane doesn't hold the same weight it use to. In fact probably none is some areas.

It is not that field approvals can't get done just that, in my experience, most mechanics can't make any money doing them because of the time consuming process and so they won't attempt it. They won't even ask. And while a DER may be required by the local FSDO guy, they may not. You will never know because your shop, like many, won't even ask.

[minton]

Plan a trip to Alaska!

[blakelewis]

I bought my plane with a v-brace installed but with no paperwork. My first annual was done by someone that wasn't familiar with the model and it was over looked. The second annual was done by a DER that caught it and was going to charge me $300 to remove it. I gave him the 337 from the archives and he had it field approved. I am in the Kansas City Missouri district. He also installed UMA instrument lighting and had it field approved. I guess DERs are special. Bob was, RIP.

[mit]

Just got off the phone with Steve Kracke from Atlee (super nice guys BTW...) anyway, he said that they should have their C180 STC amended to cover the C170 in about 5-6 months, so this might be a mute point.

But any other insight would be helpful.

Greg-

Thats what he has been saying about 8:50's for months and months. I hope they geterdone!

[GAHorn]

Hello, Greg! I got your PM just as I was headed into work and just now have an opportunity to answer.

In a "nutshell"... prior to "Change 15" it was a fairly simple thing to walk into a FSDO with a copy of someone else's Field Approved Form 337 and get another mod of the same type approved on a similar model aircraft. About 5 years ago that changed as the result of FAA coming to their senses (at risk of irritating some people who consider FAA totally whacko) as they recognized that many aircraft supposedly modified identically....actually were not .... because their inspectors were completely unqualified and/or without sufficient documentation (you should see some of the scant descriptions of modifications in some Form 337s) to determine that the subject airplane was actually modified to a previously-approved condition ...because 1) the previously approved modification was insufficiently described (Installed V-brace) ...and no description whatsoever if it was bolted, welded, how-welded, glued or duct-taped....or the source of mfr of the V-brace, etc etc.... and/or 2) the subject airplane had additonal mods which the original airplane did not...etc etc. Some airplanes were modified on supposedly-identical field-approvals...yet the actual work barely resembled each other due to insufficient documentation. (Some alternator mods are particularly suspect.)
In other words...the Field Approval process was completely out-of-control and it was impossible to continue to approve new mods based on old improperly-documented mods. So the process was re-developed. FAA will still issue Field Approvals ....BUT... one must now submit sufficient engineering data to support the modification and/or the mod must be based upon a non-STC'd approval basis that is otherwise properly documented.....AND...there must be included "Instructions for continued airworthiness" (ICA) ...i.e. a description of how to maintain/inspect the modified airplane to keep it airworthy with that mod. (You can't simply copy someone's STCd mod and ask for a field approval. Nor can you install a piece of equipment that some other airplane has approved, without enough documentation to duplicate the mod and determine it will not adversely affect your airplane.)
This means that in the OLD DAYS: You could walk into a shop, hand them an approved 337 and some parts, and they could do the mod to YOUR aircraft, hand the paperwork to an FAA inspector who could look it all over, take a peek at the airplane, and approve it. In effect, his signature became a one-time STC for your airplane, and the inspector is liable for what he signed. If you really wanted to irritate the inspector....buy the parts, do the work first and THEN ask him to put his career on the signature line.
With the new changes: Your shop must spend time (which owners don't want to pay for) to visit the FSDO, explain the mod and how it has been done to others and either provide supporting paperwork...or supply engineering data to support the mod EXACTLY as it will be done...and get the inspector's OK to proceed. THEN the shop does the work. THEN the shop must complete all paperwork to FSDO satisfaction (more time $pent which owners don't want to pay for) and convince the inspector that the change was EXACTLY as the inspector previously thought had been agreed to....and then the FSDO inspector approves it.
The problem isn't that it can't be done. The problem is mechanics know they can waste a day or two dealing with FAA they'll not be paid for, and the work doing the modification isn't worth their time.
If YOU, the OWNER wants to do this mod, then FIRST you should ask your mechanic if he'll do the physical labor if YOU get PRIOR APPROVAL from FSDO and if YOU do the legwork/paperwork so the mechanic can predict how much of his time he'll actually get paid for. It will help if you can show Form 337s and pictures of other 170s so-modified. Having 337s with modification/installation/ICA that are complete, easily understood to the point being capable of exact duplication...will go a long way to making the process easier.
Otherwise, it will take engineering support (DAR/DER) or an STC (which requires no further approval.)
I'll bet that if you personally go talk to your FAA-FSDO inspector and show him the parts, and pics of other modified airplanes, pics of your airplane, and supply the name of your shop.... that you will receive guidance on how to proceed,..and if you are willing to relieve your shop of the problems of gaining approval, they will be much happier about performing the work for you.
Hopefully some of our Members can offer you pics of their mods and paperwork to assist you with your FSDO.

By the way: The Field Approval process is easier in AK because that entire area receives different treatment from FAA. That policy is WRONG in my opinion. All regions should be governed by the same rules. (And taking your plane to AK for the mod and then coming back to the lower-48 doesn't actually work out too well in most cases, because the travel expense, and because FSDOs generally only get involved in airplanes/shops based/operated in their own region.)
Hope this generalization helps. You can do this. But it sounds as if your shop doesn't think it's profitable for them to do this for you AND do the legwork.

[bigrenna]

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[mit]

Hog wash George The FAA is the same here.

[GAHorn]

Hog wash George The FAA is the same here.

There are too many documented cases otherwise for your comment to be considered helpful.

[blakelewis]

I will take pictures of my v-brace this weekend. I will also email you a copy of my 337 which used the 337 that you have as supporting documentation.

Here is a good resource for how to put together a proposal for a field approval: "http://home.comcast.net/~dyenfd/". Look at the examples but read "http://home.comcast.net/~dyenfd/handbook.html" I talks about all the elements that are needed in the proposal, what is considered acceptable data and such and such.

I have two proposals I am working on. The Odyssey battery and a fishing rod tube. I could use pictures an Odyssey in the existing battery box. Pop the top on the box and shoot a picture.....

Blake

[mit]

Hog wash George The FAA is the same here.

There are too many documented cases otherwise for your comment to be considered helpful.

Here is their phone # to call take it up with them 907-474-0276. I haven't done a field apporval since the 90's. Maybe Alaska doesn't put up with the BS that Texas does I don't know? but when I go to FSDO or ATC they are all looking at the same regs as they do in TEXAS.

[blueldr]

My early experiences with our "Regulators", the old CAA, when I was in Fairbanks, Alaska, back in '47 to '51, was that they were very generous with their favors when it came to practicallity. I made a lot of modifications on my Stinson L-5G for cold weather operation, some of which they even copied for their own CAA airplanes. The CAA maintenance inspector at that time was a guy named Joe Miraldi and he seemed to approve of just about anything that was safe and practical. Seems as though flying life was a lot simpler and more fun in those days. Of course, I was a helluva lot younger in those days too.
I remember buying a set of Federal Skis from a doctor down in Wisconsin and they really didn't have a big enough footprint for the snow conditions around Fairbanks. I bought a set of "Kit" water skis, less bindings, from Sears Roebuck and bolted them to the bottom of the Federals and the Feds thought that was a very clever solution and readily approved it. They worked fine.
I actually got the idea from Sam White, and old Alaska bush pilot, who had an L-5 and parked right next to me at Weeks Field.
He used his airplane to run a trap line and he had a couple of small tobaggons on his skis.

[hilltop170]

Hey blueldr-
Things have changed just a little since then but you were definitely ahead of your time!

The feds in Alaska will now approve up to 10% oversized bottoms on skiis that need a little extra floatation. They won't approve Sears and Roebuck stuff though, most folks use low-friction plastic/Teflon sheets for the added area.

In my 29 years experience dealing with the FAA in Alaska, the ease at which the GA community can work with the feds ebbs and flows with the quality and attitude of the individuals in the FAA maintenance inspector ranks, even though they are looking at the same regs. When a good one comes along who has enough experience, knowledge of small planes/aviation in general, and common sense to put it all together and make good decisions, it does make it much easier to get things done and you better get everything approved and done before that person leaves the job. It may be awhile before another good one comes along. We just lost a good one in the Anchorage FSDO who retired.

Of the Field Approvals I've had done in the past 6 or 8 years in the lower 48, I can't remember any one of them that had any difficulty getting approved. I don't personally get involved and I use IAs who have good working relationships with their FAA inspectors.

There are some Alaska-specific exceptions to some FAA rules that don't apply in other states, probably fewer all the time though.

[blueldr]

When I was in Alaska, '47 to '51, the only wheel skis that I ever saw were on the Air Force C-47s. All of the GA airplanes had straight skis. Almost always wood and covered with "black iron" sheet metal with a triangular cross sectioned hardened steel runner about a foot long on the bottom to preclude side slipping on hard snow or ice. This was long before the development of Teflon. We tested a number of different covering metals, such as Aluminum, Brass, Stainless steel, etc., and found black iron to be the least "sticky" of the bunch. I was a M/Sgt. at that time and was stationed at Ladd AFB in Fairbanks with the Cold Weather Test Detachment, We ran the ski covering tests on the skis of our Noorduyn Norseman C-64 airplane. God how I loved flying that old sweetheart. It was the last one in the Air Force, and when I went down to Downsview in Toronto, Canada, in Feb. '51, to pick up the first De Haviland Beaver that the Air Force bought, they sold the Norseman to Wein. I cried.