Fuel Tank Gaskets

[Brad Brady]

(It's not an exotic material. It is the owner's inspection that qualifies it.) A simple logbook entry attesting "Replaced left fuel tank adaptor gasket PN: 0523532 with gasket fabricated by reverse engineering using 1/8" rubberized cork sheet." is sufficient on a Part 91 airplane.

Ok, I suppose this will work....It's just that with out an 8130, yellow tag, or work order number I have an issue...Maybe I'm just to anal....Brad

[c170b53]

Of course I agree with your agree and notice I'll do anything to increase my post count so I can say I play with the big boys.

[blueldr]

Requiring a paper trail for a rubberized cork gasket on a sixty year old Cessna 170 fuel filler neck is about as ridiclous a thing as I've ever heard about in aviation maintenance. What the hell are we comparing this stuff to? It's not like it is a repaired accessory on a Boeing 747 for UAL. Common sense has to come in here someplace.

[wingnut]

FAR 21.303(b)(2) empowers the aircraft owner to produce their own parts to maintain their own aircraft. There are conditions.
The big one is that the owner must participate. The definition of participation is clearly defined in the FAA Memorandum dated August 5, 1993 entitled "Definition of Owner Produced Parts".
An owner is given a lot of room here to maintain his aircraft (since he/she is primarily responsible for the maintenance and record keeping of that aircraft) with parts that do not have an 8130-3 nor "yellow tag", which really means nothing other than that the parts have been routed through a "certified vendor".
As for a mechanic installing the part, he must insure (and be of the mindset) that the part has the same fit, form, funtion, quality, etc, and willing (intelligent enough to know the difference) to install said part and sign of the logs per FAR 21.303(b)(2) and other pertinent data if applicable.
Now before people throw rocks at me, let me say this; I'm all about tracibility and conformity, but I determine that before I install a part.
I'll elaborate further tomorrow. I have a date with my wife. RIGHT NOW!! SHE SAYS!!!!!!!

Okay, she let me write one more line. If you have time, look up the FAA memorandum above. It's great.

[Brad Brady]

Requiring a paper trail for a rubberized cork gasket on a sixty year old Cessna 170 fuel filler neck is about as ridiclous a thing as I've ever heard about in aviation maintenance. What the hell are we comparing this stuff to? It's not like it is a repaired accessory on a Boeing 747 for UAL. Common sense has to come in here someplace.

BL,
It's not just ridiculous...It's freaking ridiculous But I keep pounding the fact, because right now I have found myself in the middle of a pissing match,(I hope I can say that) between a new owner and an APIA that, lets just say did marginal work.....if any at all.....On an aircraft I started to annual, and told the owner I wouldn't do any more work because it was a death trap. Now I get a call from Oke City every other day....I'm no longer working with my principal maintenance examiner.....I now am working with the lawyer arm of the FAA.....I have no problems myself....It's just a place I don't like Being....Brad

[GAHorn]

I don't blame you, Brad. Once burned by shoddy mx...will make you cautious.

A mechanic...or a pilot... each gets to make his own decisions as to what he's comfortable with. No criticism is intended by me towards anyone whose personal standards exceed the minimums. After all.... they are: Only minimum standards!

(Keep those personal standards high. You'll live long enough to miss those that didn't.)

[mschwab]

Hey Guys;

I'm an old member but have never taken advantage of using this site. I' am astounded at the thorough discussion and the wealth of brains here, and thank you sincerely for such a talented and intellligent discussion. I learned to fly in N5567C and decided to make her good-five years ago. I have a totally fresh engine from Poplar Grove, IL with new jugs etc. The wings are ready to have the tanks in. They have been stripped. I am putting new wiring and cables in also. I installed new anchor nuts at the wing roots. This summer I will strip the fusalage, put new tailwheel spring on. I will also inspect the gear box. The battery box is also in need of attention. I hope in the next year she will be a different bird. It is a lot of careful work that takes me about 4 times longer than I ever figure, but I really enjoy doing it. I am so pleased I found this group of aviators. Sincerely; Mike Schwab

[GAHorn]

In response to the msg by "wingnut", here's an excerpt from the FAA Memorandum dated August 5, 1993, "in which the assistant Chief Counsel for Regulation makes the following interpretation:

• A part does not have to be solely produced by the owner to be considered an Owner Produced Part.
• The aircraft owner must participate in the manufacture of the part in at least one of five ways for it to be considered an Owner Produced Part.
1. The owner provides the manufacturer of the part with the design or performance data.
2. The owner provides the manufacturer of the part with the materials.
3. The owner provides the manufacturer with fabrication processes or assembly methods.
4. The owner provides the manufacturer of the part with quality control procedures.
5. The owner personally supervises the manufacture of the new part.
As anyone can see, the discriminators for determining owner participation in a new part’s manufacture are very specific in the interpretation. Attachment (A) to the 1993 Memorandum clearly stipulates that the FAA would not construe the ordering of a part as participating in controlling the design, manufacture, or quality of a part. The key point is that the aircraft owner must participate in the part’s manufacture."

The foregoing was taken directly from an article by Don Dodge, Airworthiness Safety Program Manager at the South Carolina FSDO.

[c170b53]

Just going back to the original question, I know the tanks that I have (175 tanks) have 3 gaskets, an internal rubber gasket that seals the fuel from leaking out of the tank and two cork gaskets, one that is under the fuel adapter and the top of the tank and the third on top acting as a spacer between the adapter and top wing skin. What is the arrangement for the standard tanks?

[jlwild]

Jim (c170b53),

I don't know about the early 170's but my 1955 "B" model and the early 172 "A" series all have 3 gaskets. Reason I know is the left tank is original 170B and right tank and wing are early 172A parts. When I replaced both tank gaskets +/- 5 years ago I obtained them from Cessna parts and all three were the cork material. Perhaps someone can chime in on the 170 and 170A models. jlwild

[voorheesh]

To try and answer the question, I did the fuel tanks on my 1950 170 A last summer and used 3 cork/rubber gaskets just as you described for the 175 tanks. The IPC shows a gasket and a spacer and does not show the 3rd one that goes between the adapter and the upper wing skin. When I took the tanks out, they had 3 worn out gaskets/seals just as you described. I got these gaskets from Harry Dellicker in Porterville. My tanks don't leak now. BTW, Harry and Chris repair 170 tanks.