Strut Testing - where, who and what cost? (merged)

[VictorBravo]

Re: Strut Testing - where, who and what cost? (merged)

The following is my opinion as a fairly qualified airplane owner but as a non-engineer.

The wall thickness of an undamaged strut is alrerady known. X-ray will be an excellent "screening" method as you say, which will give the owner/mechanic a usable visual indication of the general presence or non-presence of corrosion.

If there is no visible corrosion on the X-ray, then it stands to reason that the wall thickness is still just about where it started, and $500 worth of wall thickness measurements are not necessary.

If an X-ray does show the existence of significant corrosion visually, then the amount of remaining wall thickness is almost a moot point... because it will likely be necessary for the strut to be repaired or replaced. That $500 worth of ultrasound inspection would IMHO be better used towards having the lower 12 inches of the strut replaced, or put toward the purchase of new struts.

You don't throw out an entire airplane because the longerons are rusted... you replace the longerons correctly and fly off into the sunset. Should the struts be any different? Patched struts are common and do not fall apart if done right.

Five of us had X-rays done for $249.00 each. Having seen the inside of my struts visually, I have no qualms about flying the airplane. That is #1 and TEN orders of magnitude more important than an AD, a factory get rich quick scheme, or a federal bureaucracy's ass covering... because the federal rule book says that I am personally responsible for the safety of the aircraft.

[dmorlo]

Re: Strut Testing - where, who and what cost? (merged)

Bill, you are correct! Safety is more important than the AD or any service bulletin. X-ray will provide a warm fuzzy on the condition of the strut and the FAA may approve its use as a tool for evaluating struts for this AD. Can you tell me if the x-ray company you used took 2 exposures (1 at a 0 degree mark and 1 90 degrees to it) for 100% coverage? I believe cost wise the ultrasonics can be competitive now that we have reduced the amount of thickness readings to be recorded. Originally I interpreted the service bulletin to require 720 readings using the 1/4" grid but I have since talked to TC Engineer and we only need to scan the 1/4" circumference 48 times over the 12" length for a total of 48 readings. Each circumference will be scanned and the lowest reading recorded.

David Orlosky
Level III, iTi

[VictorBravo]

Re: Strut Testing - where, who and what cost? (merged)

Our local NDT specialist is also a Level 3.

He said clearly that when X-ray'ing a streamlined strut tube, the vertical axis picture is the only one that needs to be done. A picture taken from the front of the streamline tube strut will not work, because there is no part of the "wall" that is nearly perpendicular to the film or the camera.

Also, since the struts are 3 or 4 inches in the fore-aft dimension, shooting through that much metal is difficult and does not show any useful visualization. If it were a round tube or a square tube, then 0 and 90 degree shots are appropriate.

We'll be writing up the procedure and dimensions today and tomorrow, and submitting it to the FAA.

Bill

[VictorBravo]

Re: Strut Testing - where, who and what cost? (merged)

CORRECTION our local inspector is a level 2 X-ray NDT and an FAA approved repair station. Apologies for the error.

[AKbrew]

Re: Strut Testing - where, who and what cost? (merged)

I had my struts x-rayed yesterday by Alaska Industrial X-Ray. After evaluating the x-ray they issued me the following log book entry: "X-ray inspection of the Taylorcraft Wing Struts for corrosion in compliance with A.D. 2007-16-14 and approval letter dated 9/12/07 was accomplished. No significant corrosion was found and the following struts are considered airworthy. Corrosion Inhibitor Procedure found in S.B. No. 2007-001 shall be accomplished prior to the return of service." The entry is signed by the inspector, includes the repair station ID and the inspector's certification #. This company has been doing Piper strut X-rays since the Piper AD came out. (Mid 70's?). They said they have x-rayed 12 T-Crafts here in Alaska so far, and found one strut with some corrosion. The cost was $180.

[Guest]

Re: Strut Testing - where, who and what cost? (merged)

I had my struts x-rayed yesterday by Alaska Industrial X-Ray. After evaluating the x-ray they issued me the following log book entry: "X-ray inspection of the Taylorcraft Wing Struts for corrosion in compliance with A.D. 2007-16-14 and approval letter dated 9/12/07 was accomplished. No significant corrosion was found and the following struts are considered airworthy. Corrosion Inhibitor Procedure found in S.B. No. 2007-001 shall be accomplished prior to the return of service." The entry is signed by the inspector, includes the repair station ID and the inspector's certification #. This company has been doing Piper strut X-rays since the Piper AD came out. (Mid 70's?). They said they have x-rayed 12 T-Crafts here in Alaska so far, and found one strut with some corrosion. The cost was $180.

I understood that X-ray was NOT approved.

Can you post this 9/12/07 letter? or tell us more about it?

Dave.

[AKbrew]

Re: Strut Testing - where, who and what cost? (merged)

Hello Drude,

I'll call Alaska Industrial X-Ray tomorrow and see if they will fax me a copy of the approval letter. If they send me a fax I will post it. I spoke with them today and they have been doing AD compliance x-rays on Pipers and Maules for many years, and as stated in other threads, the AD for Taylorcrafts closely mirrors the Piper AD. I asked them for confirmation they had an approval letter in hand from the FAA and he read it to me verbatim over the phone. Again, I'll see if I can get a fax copy for all to view.

[Guest]

Re: Strut Testing - where, who and what cost? (merged)

Hello Drude,

I'll call Alaska Industrial X-Ray tomorrow and see if they will fax me a copy of the approval letter. If they send me a fax I will post it. I spoke with them today and they have been doing AD compliance x-rays on Pipers and Maules for many years, and as stated in other threads, the AD for Taylorcrafts closely mirrors the Piper AD. I asked them for confirmation they had an approval letter in hand from the FAA and he read it to me verbatim over the phone. Again, I'll see if I can get a fax copy for all to view.

Thanks, did they do it with struts on or off?

[AKbrew]

Re: Strut Testing - where, who and what cost? (merged)

Struts were on. I called them up and three hours later I had the AD compliance sticker for my log book. Attached is the letter from the FAA approving their AMOC.

[AKbrew]

Re: Strut Testing - where, who and what cost? (merged)

I forgot to mention...Alaska X-Ray also told me today they have rejected ONE out of forty struts tested so far.

[Guest]

Re: Strut Testing - where, who and what cost? (merged)

Thanks AKbrew, another question if you don't mind.

I can't read rhe print on the letter.

Can you tell me if the letter says that leaving the struts on is ok?

Thanks, Dave

[Mike]

Re: Strut Testing - where, who and what cost? (merged)

Struts were on. I called them up and three hours later I had the AD compliance sticker for my log book. Attached is the letter from the FAA approving their AMOC.

How do they treat the struts with corrosion inhibitor with the struts in place?

[VictorBravo]

Re: Strut Testing - where, who and what cost? (merged)

Struts were on. Attached is the letter from the FAA approving their AMOC.

Fan-Tastic !! Good job AKBrew !!!

My local X-ray place will be supplying me today with the procedure used on our five ships here in Los Angeles... I'll be sending that along to Andy McAnaul as soon as I get it.

Thanks for posting the letter. Perhaps you can also post the actual procedure that they accepted, so that others can use it as a basis for getting an AMOC of their own.

Bill Berle

[AKbrew]

Re: Strut Testing - where, who and what cost? (merged)

OK Gang,

I spent some time on the phone with my IA today deciphering AD 2007-16-14, SB 2007-001, and the AMOC for X-Ray. We came away with a plot that has more twists and turns than a Harlequin Romance Novel that was left out in the rain on a windy day.

First "The Strange": AD 2007-16-14 DOES NOT require treatment of struts "which pass inspection using corrosion inhibitor procedure in Taylorcraft Service Bulletin No. 2007-001 or an equivalent procedure prior to returning them to service." If you follow the AD, take the struts of your airplane, and have them tested using Eddy Current or Ultrasound and they pass...you are good to go.

Now the "Bad News": The AMOC approving x-ray as a method of inspection DOES REQUIRE "treatment of struts which pass inspection using corrosion inhibitor procedure in Taylorcraft Service Bulletin No. 2007-001 or an equivalent procedure prior to returning them to service." SB 2007-001 reads as follows: CORROSION INHIBITOR PROCEDURE:
Before installing reusable struts, treat each strut for internal corrosion protection per the following procedure:
a. Inject one quart of warm raw Linseed Oil, Paralketone or CRC3 (LPS Heavy Duty Rust Inhibitor Type 3) into the strut.
b. Plug open holes in the strut and slosh oil until interior of strut is thoroughly coated.
c. Drain oil from strut through an open hole.
d. Reinstall strut on aircraft and check rigging per LIFT STRUT WING LEVELING PROCEDURE below.
That's right folks...to comply with SB 2007-001 you must REMOVE the struts from the aircraft. To comply with the AMOC for X-ray you must comply with SB 2007-001. (At this point the IA is saying "well...that doesn't make much sense.")

And now "The Good News": The IA said the corrosion inhibitor procedure really isn't that big of a deal because you can do it by removing ONE STRUT AT A TIME. You take one off, slosh some of the treating oil around the inside of it, put it back on, then take the next one off. According to the IA, doing them one at a time eliminates the need to re-rig everything (that's him talking...I don't have a clue).

So...bottom line is the way the AMOC is currently written you don't have to remove the struts for the X-ray (very convenient since they can come right out to your hangar or tie-down spot and do the x-ray), BUT you have to remove one strut at a time to slosh the oil around inside them. (Actually, your A&P)

That's all I know so far (probably even more than I know!). No luck getting a copy of the actual AMOC procedure from Alaska X-ray...hey, it's Friday and hunting season in Alaska, what did you expect? I'll try to get in touch with them on Monday.

Tomorrow I drive to Kenai to pick up my new (to me) Edo 1400 floats. Yeehaw! Maybe by next summer I can post a cool picture like Dano T and Dick Smith. The Dalmatians will have to stay home this time though...not enough room in the back of the truck for dogs AND the Landes skis!

[jmvolpp]

Re: Strut Testing - where, who and what cost? (merged)

I picked up N44305 struts from successful eddy current testing at IDM (in former UAL facility at IND) 4 days ago. Nice people, cool facility, cost $250. Now to complete inspection of fittings and reassemble. Opinion forthcoming when done, FWIW.

Mike V.