Strut Airworthiness Directive (AD) (merged VI)

[alwaysoar]

Re: Strut Airworthiness Directive (AD) (merged I)

Hi B-52 Norm,
I assume I'm the Ed who's making you cry. I do my own work. I'm an A&P and very conscientious about maintenance on my airplane. But I am getting fed up with old-plane problems. I've owned at least a dozen of them, and it goes on and on.

One of my biggest frustrations now is the lack of definitive direction from the powers that be here in the Foundation. To wit:

1. Owner manufactured--knowledgable people debate this here. Will the real "owner manufactured" please stand up.

2. My questions--usually unanswered (e.g. is a strut "repaired" if the tubing is replaced and the original fittings welded into new tubing? I think it is, but I'm not sure.)

3. How best to inspect the strut fuselage fitting that failed on the seaplane in Oregon. I asked, but as often occurs, the message comes down from gurus to do something ("inspect it") after having seen pictures of the failure himself, without saying how best to accomplish this. I can figure something out for myself pretty well, but I want to be certain I'm doing it the best possible way.

There is a lot of really good information and there are a lot of really good people here, but it seems there is always something lacking that gives me a sense of direction in certain areas, such as the strut issue.

Ed@BTV VT
TF 527

[Guest]

Re: Strut Airworthiness Directive (AD) (merged I)

Hi B-52 Norm,
I assume I'm the Ed who's making you cry. I do my own work. I'm an A&P and very conscientious about maintenance on my airplane. But I am getting fed up with old-plane problems. I've owned at least a dozen of them, and it goes on and on.

One of my biggest frustrations now is the lack of definitive direction from the powers that be here in the Foundation. To wit:

1. Owner manufactured--knowledgable people debate this here. Will the real "owner manufactured" please stand up.

2. My questions--usually unanswered (e.g. is a strut "repaired" if the tubing is replaced and the original fittings welded into new tubing? I think it is, but I'm not sure.)

3. How best to inspect the strut fuselage fitting that failed on the seaplane in Oregon. I asked, but as often occurs, the message comes down from gurus to do something ("inspect it") after having seen pictures of the failure himself, without saying how best to accomplish this. I can figure something out for myself pretty well, but I want to be certain I'm doing it the best possible way.

There is a lot of really good information and there are a lot of really good people here, but it seems there is always something lacking that gives me a sense of direction in certain areas, such as the strut issue.

Ed@BTV VT
TF 527

Hi Ed, hope this helps you. I am answering to help you out if I can I have nothing to do with the Foundation other than I joined this year.

1. Here is the FAA position on owner produced parts whatever anybody else thinks doesn't count its been the same since 1989. Also you will need drawings and process info about the original part.

This is the link to the AC=> http://rgl.faa.gov/Regulatory_and_Gu...ighlight=43-18

Here is the reg

§ 21.303 Replacement and modification parts.
(a) Except as provided in paragraph (b) of this section, no person may produce a modification or replacement part for sale for installation on a type certificated product unless it is produced pursuant to a Parts Manufacturer Approval issued under this subpart.

(b) This section does not apply to the following:

(1) Parts produced under a type or production certificate.

(2) Parts produced by an owner or operator for maintaining or altering his own product.

(3) Parts produced under an FAA Technical Standard Order.

(4) Standard parts (such as bolts and nuts) conforming to established industry or U.S. specifications.

(c) An application for a Parts Manufacturer Approval is made to the Manager of the Aircraft Certification Office for the geographic area in which the manufacturing facility is located and must include the following:

(1) The identity of the product on which the part is to be installed.

(2) The name and address of the manufacturing facilities at which these parts are to be manufactured.

(3) The design of the part, which consists of—

(i) Drawings and specifications necessary to show the configuration of the part; and

(ii) Information on dimensions, materials, and processes necessary to define the structural strength of the part.

(4) Test reports and computations necessary to show that the design of the part meets the airworthiness requirements of the Federal Aviation Regulations applicable to the product on which the part is to be installed, unless the applicant shows that the design of the part is identical to the design of a part that is covered under a type certificate. If the design of the part was obtained by a licensing agreement, evidence of that agreement must be furnished.

(d) An applicant is entitled to a Parts Manufacturer Approval for a replacement or modification part if—

(1) The Administrator finds, upon examination of the design and after completing all tests and inspections, that the design meets the airworthiness requirements of the Federal Aviation Regulations applicable to the product on which the part is to be installed; and

(2) He submits a statement certifying that he has established the fabrication inspection system required by paragraph (h) of this section.

(e) Each applicant for a Parts Manufacturer Approval must allow the Administrator to make any inspection or test necessary to determine compliance with the applicable Federal Aviation Regulations. However, unless otherwise authorized by the Administrator—

(1) No part may be presented to the Administrator for an inspection or test unless compliance with paragraphs (f)(2) through (4) of this section has been shown for that part; and

(2) No change may be made to a part between the time that compliance with paragraphs (f)(2) through (4) of this section is shown for that part and the time that the part is presented to the Administrator for the inspection or test.

(f) Each applicant for a Parts Manufacturer Approval must make all inspections and tests necessary to determine—

(1) Compliance with the applicable airworthiness requirements;

(2) That materials conform to the specifications in the design;

(3) That the part conforms to the drawings in the design; and

(4) That the fabrication processes, construction, and assembly conform to those specified in the design.

(g) The Administrator does not issue a Parts Manufacturer Approval if the manufacturing facilities for the part are located outside of the United States, unless the Administrator finds that the location of the manufacturing facilities places no burden on the FAA in administering applicable airworthiness requirements.

(h) Each holder of a Parts Manufacturer Approval shall establish and maintain a fabrication inspection system that ensures that each completed part conforms to its design data and is safe for installation on applicable type certificated products. The system shall include the following:

(1) Incoming materials used in the finished part must be as specified in the design data.

(2) Incoming materials must be properly identified if their physical and chemical properties cannot otherwise be readily and accurately determined.

(3) Materials subject to damage and deterioration must be suitably stored and adequately protected.

(4) Processes affecting the quality and safety of the finished product must be accomplished in accordance with acceptable specifications.

(5) Parts in process must be inspected for conformity with the design data at points in production where accurate determination can be made. Statistical quality control procedures may be employed where it is shown that a satisfactory level of quality will be maintained for the particular part involved.

(6) Current design drawings must be readily available to manufacturing and inspection personnel, and used when necessary.

(7) Major changes to the basic design must be adequately controlled and approved before being incorporated in the finished part.

(8) Rejected materials and components must be segregated and identified in such a manner as to preclude their use in the finished part.

(9) Inspection records must be maintained, identified with the completed part, where practicable, and retained in the manufacturer's file for a period of at least 2 years after the part has been completed.

(i) A Parts Manufacturer Approval issued under this section is not transferable and is effective until surrendered or withdrawn or otherwise terminated by the Administrator.

(j) The holder of a Parts Manufacturer Approval shall notify the FAA in writing within 10 days from the date the manufacturing facility at which the parts are manufactured is relocated or expanded to include additional facilities at other locations.

(k) Each holder of a Parts Manufacturer Approval shall determine that each completed part conforms to the design data and is safe for installation on type certificated products.

[Amdt. 21–38, 37 FR 10659, May 26, 1972, as amended by Amdt. 21–41, 39 FR 41965, Dec. 4, 1974; Amdt. 21–67, 54 FR 39291, Sept. 25, 1989]


2. Yes in my opinion it is a repair and as you described it. I am an a&p IA I can tell you that when signing the 337 thats how I would view and sign for it. Your IA should answer that for you. Foundation thoughts don't count regarding that but you may need drawings from them depending on repair complexity. Get a feild approval if you are nervous. I don't recall any service manual entries about that repair for that matter I don't recall a real service manual at all. I understand that I my opinion about the repair may incorrect so leave some room for that. The acid test is do a feild approval and see what they say before you do teh repair. I am gonna search AC43.13-1B later today to double check but wanted to send this before I left for work.

3. I have not seen the pictures but the engineer described it as the fitting cavities had fabric stuffed in them during recover and that combined with debris accumulated during use held moisture. You have to use you imagination but there are very few cavities so there are not that many possibilities.

Hope this helps, Dave

[Ron Greene]

Re: Strut Airworthiness Directive (AD) (merged I)

Ed,

This link will take you to a good article.

http://www.iflyamerica.org/ownerproducedparts.asp

Ron Greene

[Ragwing nut]

Re: Strut Airworthiness Directive (AD) (merged I)

Fellow Taylorcraft owners,

MODERATORS, FEEL FREE TO MOVE THIS THREAD TO THE LOCATION BEST SUITED.

For starters let me introduce myself. I am a Sr. Manufacturing Engineer for the premier high end domestic bicycle manufacturer. The scope of my work involves manipulating a host of tubing materials…. aluminum, 4130 steel, titanium, and of course carbon. We have a very complete and extensive testing department. In questioning some of my fellow engineers, test engineers and QC employees who regularly use ultrasonic and eddy current testing in their job descriptions, they unanimously thought that NEITHER would be an effective method of determining if varying degrees of corrosion existed inside a closed tube structure. Always the skeptic, I set out to prove or disprove the use of Ultrasonic testing as a capable way of testing for strut corrosion. I borrowed our very portable PANAMETRICS MODEL 22 ULTRASONIC THICKNESS GAGE for the weekend. I taught myself the use and calibration of the unit and proceeded to test the LH front strut on my 1938 Taylorcraft Model BF. I set out to neither advocate nor condemn the use of Ultrasonic equipment, only to educate myself in the use and applicability in our strut dilemma. I intentionally set up a series of test parameters that are easily duplicated for STRUTS ON THE AIRCRAFT should results prove useable.

Here are the FACTS relevant to my testing.

-Testing done over the timeframe of 08/18/07 to 08/19/07 at 70degrees and 70% relative humidity.
-Tests completed on what I believe to be an ORIGINAL pre-war Taylorcraft strut. Ellipse dimensions as indicated….major axis 3.000”, minor axis 1.310” (over painted surfaces).
-Panametrics Model 22 unit calibrated per pg. 4.3 of Manual # 910-019B.
Calibration sample .181”/.338”. mild steel.
-Unit set to read in .xxx” (three decimal place…. thousandths)
-Paint thickness sample removed from strut as measured with micrometer…approx .003” as mic’d (3) times in (3) different locations.
-Couplant fluid used was provided by manufacturer.
-Transducer calibration was rechecked and recorded at each row end (54 times total during test)
-(8) individual readings were also taken along the approx neutral axis of the remaining full length of strut at 12” intervals up to the extreme outboard end(wing attach).


I set out by removing the paint from the bottom surface of the lower portion of the LH front strut. I then layed out a grid pattern of approx ½” squares on both the upper (painted) and lower (unpainted) surfaces. Grids were labeled A1 thru G-27. Some areas were not conducive to measurements with the probe such as welds and extreme trailing edges. In total I took 291 readings on this strut using the grid layout as a template.

Preliminary findings indicate extremely consistent metal thickness the entire length of the strut, with the lower 12” averaging .038” +.003/-.002 over 137 readings. I have not run the statistical analysis on my findings yet but have satisfied myself that the Ultrasonic unit is an excellent tool for determining metal thickness on what I believe to be a very intact and un-corroded strut. Findings over the painted surface yield a thickness of .041” +.003/-.001 over 154 readings. These latter reading are consistent with the sample paint thickness of .003”. Another observation that I made during the testing included the following: “ratting derbis” as removed thru the upper wing attach hole amounted to nearly a half teaspoon and consisted almost entirely of weld scale and chips as a result of ( I believe) drilling the upper attach fitting at the point of manufacture.

I would like to duplicate this test on a KNOWN CORRODED strut end. Can someone (Kevin M,, Mike R.?) PLEASE hacksaw off and send me the lower 24” or so of some known defective, corroded struts as soon as possible! Should results of this further testing prove conclusive in identifying internal corrosion, I would advocate same to the FAA . Please reply to forum, e-mail (rockriverrifle “at” hotmail.com) or call me evenings at 920-648-three four six nine to discuss or make suggestions to continue testing.

THIS COULD RESULT IN A VERY USER FRIENDLY, FAIRLY QUICK, ON PLANE TEST METHOD FOR OUR TAYLORCRAFT FLEET.

Call or email me. I have several junk struts of varying degrees of corrosion.

Mike

[Guest]

Re: Strut Airworthiness Directive (AD) (merged I)

Ed,

This link will take you to a good article.

http://www.iflyamerica.org/ownerproducedparts.asp

Ron Greene

Very nice article Ron, thanks.

[stormman]

Re: Strut Airworthiness Directive (AD) (merged I)

Ed Said
"
Our fathers and grandfathers were tormented and died in the valiant service of making aviation a safe and proud vocation. In these machines they made history and that history is of the greatest consequence to modern life. For those of us that preserve and "
Thats what makes me cry Ed not your Great question and non whining approach
I have to go on the

" I fix it and it was that way from the factory " thing as there is too much Cover Your Ass stuff out there now. I feel a lot better making a jig and welding up new struts than flying with a part im not sure of as airworthy because of Red tape involved with changing it .
"If it ant broke don't fix it" never worked well for me in the past and im sure a lot of the Guys of the Tribe feel this way too. As i said its CYA and your getting a lot of responces for your post . Robert Lees from across the pond has great pics of almost everything and he's far far away from the USA
so to answer you questions
# 1 I will stand up but " I do not recollect having sex with that woman"
#2 I think one of the tribe guys answered that for you ,I say ya but see
#1 above for the correct answer
#3 Your way is probably the best possible way . I remember a guy ( not me of course ) who once safety cabled the struts together for a ferry flight.
But like you I like to see all available options and make the selection.

[waltermrich]

Re: Strut Airworthiness Directive (AD) (merged I)

Could someone tell me in plain English what Alternative Methods of Compliance (AMOCs) means as written on the strut AD, Thanks

[flyguy]

Re: Strut Airworthiness Directive (AD) (merged I)

I believe it means "I wish to use another method of complying with the AD, here it is, will you approve it?" (I wouldn't hold my breath on that possibility.)
DC

[Guest]

Re: Strut Airworthiness Directive (AD) (merged I)

I believe it means "I wish to use another method of complying with the AD, here it is, will you approve it?" (I wouldn't hold my breath on that possibility.)
DC

That's it exactly

[flyguy]

Re: Strut Airworthiness Directive (AD) (merged I)

There are Ultrasonic thickness testers in use by the guys who do head porting on heads for race cars and street machines. They are not uncommon and very accurate as discribed above. The last shop I had run a flow test on my ported chevy heads had one. It was a very small operation.

I had not seen this AD biz until today, believe it or not, and was rather shocked when I did read the thread.

Someone is going to make a fortune off of this and the lucky ones of us with open struts that test ok are going to have a pain to deal with forever.

On the other hand, if the struts are open at the top (I hadn't even thought much about that,) then they will in fact "breath" as the temperature changes and any condensate produced will run down to the bottom to do it's damage.

Guess we OUGHT to do a serious check on them. What a pain though.

Think that makes me GROUNDED.
DC

[Robert Lees]

How to post your comment on the FAA website

As of today, their are only FOUR comments posted (although some folk might have mailed their comments).

To view the comments, go to http://dms.dot.gov and click the "Simple Search" button. Type in 28478 and hit "search".

To enter a comment, go to the same website, click on "Comment/Submissions", then click the "Continue" button (no registration is required). In the Docket ID box, type in 28478, and then fill in the rest of the form.

[Dano"T"]

Re: Strut Airworthiness Directive (AD) (merged I)

Guys and gals....even if you mailed your concerns...take the time to do the on-line comments.....Rob gave excellent instructions.....there's power in numbers.

[VictorBravo]

Re: Strut Airworthiness Directive (AD) (merged I)

Below is the comment I posted on the docket, after following Rob's instructions. Anyone who wishes to use any part of what I wrote for the purpose of leaving their own comment is free to do so. I strongly agree that it is quite important for all of us to leave a comment.

----------------------

I am an owner/operator of the type of aircraft affected by this AD. I believe that several important and potentially mitigating factors have not been adequately considered during the preparation of this AD.

On the TECHNICAL side, I do not believe there is any greater history of Taylorcraft aircraft being lost due to failure of the wing struts than on any other similar type. The recent tragic loss of a Taylorcraft has been reliably reported as NOT being a failure of the strut. It appears that the AD was based on a Service Bulletin from the TC holder, and this SB was positioned and written with the specific intent to create sales of replacement struts.

The SB bypassed more than one FAA approved method of compliance (such as the Piper strut style punch test, X-ray inspection, Borescope inspection). When the FAA upgraded this SB to an AD, it appears (to those of us "on the street") that these other methods of inspection had been overlooked without cause.

For example, the punch test inspection allowed by the Piper strut AD appears to provide a safe and easy method, and to my knowledge there has been no need for the FAA to amend the Piper AD due to ineffectiveness of this inspection. SEVERAL qualified engineers or inspectors (both in and not in our owner's club) have voiced their opinion that X-ray will give a superior visual depiction of any corrosion inside the strut, yet X-ray is not permitted in this AD.

There is also a simple and valuable option of drilling an inspection hole near the lower end of the strut and performing a visual inspection with a small diameter fiber optic viewing device. This would yield a direct, clear verification of the type and amount of corrosion or moisture inside the strut. Yet this was not permitted as part of the AD.

The AD also does not address the fact that three or four separate sizes, wall thicknesses, and steel alloys were and are approved for struts on this aircraft. Struts are approved with as little as ( I believe) .035 and as much as .049 wall, from 1020 mild steel to 4130, and varying major and minor outside dimensions. As such, an .049 wall 4130 strut of a larger size can obviously tolerate a deeper or worse level of corrosion than a thin wall mild steel strut... but none of this has been addressed in the AD.

I believe I can speak for the vast majority of owners when I say nobody wants to fly with corroded or dangerous struts, but I also believe that a majority of owners believe that 1) this AD was created too hastily and with not enough consideration for acceptable methods of inspection, and 2)the AD was far too hasty because the recent crash was reportedly not a wing strut failure.

On the BUSINESS side, there are also non-technical factors which the FAA should have considered because there is a POSSIBILITY that the FAA has been used as an unwitting tool in what may ultimately be a marketing gimmick.

First, The current Type Certificate holder has a public history of questionable business practices involving his ability to manufacture and sell aircraft or parts for this aircraft. It was made public that (during bankruptcy proceedings that were just a few months before this AD was created) he claimed something to the effect that he was positioned for a large increase in business related to an upcoming Service Bulletin requiring the replacement of hundreds of wing struts. When asked publicly by myself and others in our type club what the statistics were on inflight strut failures on Taylorcrafts, there was no answer from the TC holder.

It was no surprise that the SB issued by "the factory" was little more than an order form for thousands of dollars in new struts. Although not _technically_ germane to this AD issue, the current TC holder is known to have removed airworthy used parts from one customer's aircraft and sold them as new replacement parts to another customer without the knowledge of the aircraft owner... to make a quick profit selling replacement parts. What IS germane to the AD issue is that when the TC holder lobbied the FAA to issue an AD, the FAA may not have taken all the mitigating technical and "business practices" factors into account, and may have not realized that (in the opinion of many Taylorcraft owners)the TC holder was hoping to use the FAA and the AD process as the marketing division for his parts department.

In short, for many of us it appears that "General Motors has convinced the DOT to recall thousands of trucks and force the owners to buy new $1000 transmissions, because the brakes failed on a truck recently and caused an accident"

If I do not have my facts correct on any or all of this please feel free to let me know which facts I have mistaken.

However I do wish to point out that the FAA/NTSB should have taken the time to communicate with the Taylorcraft community at the beginning and during the creation of this AD. The internet would have facilitated a very efficient and instant dialog between all concerned parties in this matter. There is a very active exchange of information and many highly qualified people that participate, as well as a large sampling of Taylorcraft owners and operators that SHOULD have been part of the discussion.

It appears that there are several valid factors that would mitigate this AD to one degree or another. The FAA should reconsider how this AD is written, and allow additional methods of inspection, and re-focus the AD so that it deals with the part of the airframe that DID fail and cause a crash.

William M. Berle
N29544 s/n 2387
Canoga Park, CA

[Richard Boyer]

Re: Strut Airworthiness Directive (AD) (merged I)

How long does it take for a comment to show up?

[VictorBravo]

Re: Strut Airworthiness Directive (AD) (merged I)

I don't know but mine has not shown up and I did not get an e-mail verification.