Cessna 120-140 Association

Guys:
Everyone is 337 happy. If you ask an FAA inspector, he'll probably tell you you need a 337. If you ask most IAs under the age of 60, they'll probably tell you you need a 337. Bottom line, you need a 337 if it's a major modification. Look in Part 43 Appendix A under major airframe modifications. If there's nothing there that fits, it is not a major modification and you don't need a 337. TMSAISTI!

(I didn't look, but if I were a betting man, I'd say no, it's a minor modification and you can do it with a log book entry.)

TMSAISTI! ???????

(I don't know what it means, but if I were a betting man I'd say I probably don't want to know!)

John, I'm not 337 happy. I just have learned in 40 years of airplane ownership there's very little that can be done on an airplane without some form of documentation. I guess I should have asked: "How did you document the installation of the VW latch?" I'll be sure to look at all the available manuals before asking a question in the future!

I'd still like to know how Tamer A and Martin documented their installations.

Steve

6643 wrote: ↑Sat May 04, 2019 9:17 am
(I didn't look, but if I were a betting man, I'd say no, it's a minor modification and you can do it with a log book entry.)

Thank you John.

8424 wrote: ↑Sat May 04, 2019 3:09 pm TMSAISTI! ???????

(I don't know what it means, but if I were a betting man I'd say I probably don't want to know!)

That's My Story And I'm Sticking To It.

John, I'm not 337 happy. I just have learned in 40 years of airplane ownership there's very little that can be done on an airplane without some form of documentation.

True, some sort of documentation. In this case, a log book entry. Here is the applicable section from the regs. Anything not listed in section (a)(1) below is a minor modification and can be accomplished with a log book entry.

Appendix A to Part 43 - Major Alterations, Major Repairs, and Preventive Maintenance
(a)Major alterations -

(1)Airframe major alterations. Alterations of the following parts and alterations of the following types, when not listed in the aircraft specifications issued by the FAA, are airframe major alterations:

(i) Wings.

(ii) Tail surfaces.

(iii) Fuselage.

(iv) Engine mounts.

(v) Control system.

(vi) Landing gear.

(vii) Hull or floats.

(viii) Elements of an airframe including spars, ribs, fittings, shock absorbers, bracing, cowling, fairings, and balance weights.

(ix) Hydraulic and electrical actuating system of components.

(x) Rotor blades.

(xi) Changes to the empty weight or empty balance which result in an increase in the maximum certificated weight or center of gravity limits of the aircraft.

(xii) Changes to the basic design of the fuel, oil, cooling, heating, cabin pressurization, electrical, hydraulic, de-icing, or exhaust systems.

(xiii) Changes to the wing or to fixed or movable control surfaces which affect flutter and vibration characteristics.

So, I would write something like "Removed existing side window latches and replaced with Cessna 150 style latches. All work accomplished In accordance with AC43.13-1b"

John C is entirely correct!!! I was wondering when he would jump in.
I have "preached" on this subject in years past - if the archives were available and I was capable, I could save time.
The FAA has a guidebook for their inspectors that covers field approvals and issues such as this - I just can't cite the # at the moment - it is available at faa.gov.
Unless it has changed, it states that too many A&Ps and IAs are seeking field approvals for items that do not require them and goes on to state that the inspector should return the request and IIRC admonish the requestor to do the job given to him/her with the ticket you have acquired! Granted, there is no standardization in the FAA and among the FSDO - in the old days when everything had to go thru the FSDO, as John has said, the comment was to send the paperwork to them. Maybe some job security in it! But now, with their work load, many of the 337 items are sent directly to OK City with just the IA sign off. I'm not implying that this a 337 issue - doesn't even approach that and can be easily covered with the succinct verbiage as John stated.

Many years ago, there was a FAA Washington guy ,who wrote many of the regulations, who made the "talk circuit", Bill O'Brien, who has passed away, and was so well respected, that an award is given in his name. I knew him and was a subject of some of his seminar attention. In passing in the hall, I asked him for a good explanation for the difference in "major" and "minor'. He responded with three short questions which if answered "yes", then the issue was " minor" - I went so far to ask him to write them down which he did on a torn-off piece of paper. I probably can't find it now but the essence of what he said was (and was one of the questions) "if the alteration failed, could the aircraft be landed safely"! IIRC all three questions had to do with safety and not procedural.

From a 90 year old who soloed in July 1946 and has been a student of the "system" since then and still learning and flying.

It's Sunday morning, so will the ushers pass the collection plate!

Great dialog...thanks for the good insight and information. This is what makes these forums work. I appreciate the privilege being a part of it.

Steve

Per everyone else, no 337 required. Logbook entry is all that's needed. Mine were done by the previous owner.

I think the arguments against a 337 makes all the sense in the world, but the log book entry would need to be an A&P correct? Or could this fall under "Replacing Side Windows" as pilot/owner allowed work?

Ray

You can check under Part 43 Appendix A for that.

It list what is preventive maintenance. Those are the things a pilot can do and the sign off.

Go to FAA.GOV under then look under FARS.

If this is your first time doing any sign offs, check with an A&P that will work with you and have them show you how to do them.

Good luck,

Rick

I wouldn't call it "maintenance," so it wouldn't fall under preventive maintenance. It's a minor modification. A log entry by an A&P should be sufficient.