Anyone on the forum with a NDT/Inspection background?

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joea
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Anyone on the forum with a NDT/Inspection background?

Post by joea » Wed Apr 06, 2011 22:01

Is there anyone on the forum with a NDT/Inspection background?

We need to find someone who is very experienced in inspection, hopefully in the aircraft industry.

If so please chime in or PM or Email me.

Thanks,

Joe A

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Re: Anyone on the forum with a NDT/Inspection background?

Post by Jerry Jackson » Thu Apr 07, 2011 04:19

I did a lot of work designing and manufacturing ultrasonic instruments and transducers. I know the principles of eddy current but not much practical experience.

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Re: Anyone on the forum with a NDT/Inspection background?

Post by joea » Fri Apr 08, 2011 07:07

Jerry,

Thanks and we are looking for people with experience in inspection and corrosion. The ANC FAA are saying that anything over ONE THOUSANDS of an inch on any piece of metal is not acceptable and must be corrected. After that its not difficult to see that they have not worked on aluminum much. Take a piece of new aluminum, sit it out on the ramp next to your plane and within a week the oxidation (aka corrosion) will show up on the metal. Is this grounding or dangerous? We know its not but now have to prove it to the feds...

Thx,

Joe

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Re: Anyone on the forum with a NDT/Inspection background?

Post by Zero6echo » Fri Apr 08, 2011 17:43

For what it's worth, I work in an Inspection Department for a 121 carrier (name witheld to protect the innocent) and any amount of corrosion is unacceptable. When corrosion meeting your example is found the area is repaired IAW maufacturer's recommendations and a deferral is issued to accomplish repetitive inspections until the area is permanently repaired. Aging Aircraft is a significant program these days and specific work cards are built to address it. Of course that's easy to say since the manufacturer's of our fleet types have the program already written, we just have to implement it. So I guess what I'm saying is corrosion is corrosion, regardless of the level.

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Re: Anyone on the forum with a NDT/Inspection background?

Post by Jerry Jackson » Sat Apr 09, 2011 06:22

Joe

This seems to be more of a metalurgical issue than a NDI matter. Maybe their position is based on a judgement that once started, corrosion never stops on its own accord. It just keeps getting worse until remedial action is taken.

I will say that UT is capable of resolving one thousandths but it requires equipment that operates at high frequency in order to get good resolution. Equipment operating at 10 Mhz or less are not suitable for that purpose. Also, even high frequency equipment can give poor results if either surface of the metal rough from extensive, uneven corrosion. The problem in those cases is that the broad beam encounters many different thicknesss and the resulting echo is smeared to a degree that it lacks precision. In fact, if the metal is rough then it does not have a well-defined thickness.

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Re: Anyone on the forum with a NDT/Inspection background?

Post by seaheli » Sat Apr 09, 2011 15:29

Zero6echo wrote:For what it's worth, I work in an Inspection Department for a 121 carrier (name witheld to protect the innocent) and any amount of corrosion is unacceptable. When corrosion meeting your example is found the area is repaired IAW maufacturer's recommendations and a deferral is issued to accomplish repetitive inspections until the area is permanently repaired. Aging Aircraft is a significant program these days and specific work cards are built to address it. Of course that's easy to say since the manufacturer's of our fleet types have the program already written, we just have to implement it. So I guess what I'm saying is corrosion is corrosion, regardless of the level.
Every aircraft manufacturer and/or "carrier (that writes their own service manuals)" has different limits of acceptance!

Corrosion can be stopped and treated!

Let these gentleman review every avenue possible without statements that corrosion is unacceptable.

Charles

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Re: Anyone on the forum with a NDT/Inspection background?

Post by joea » Sun Apr 10, 2011 17:00

The problem is, (I feel) that the people putting up these standards have never worked out in the field. .001 of anything is just plain silly IMHO as aluminum oxidises this much naturally so every airplane in the world would be illegal.

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Re: Anyone on the forum with a NDT/Inspection background?

Post by kyleb » Sun Apr 10, 2011 17:46

joea wrote:The problem is, (I feel) that the people putting up these standards have never worked out in the field. .001 of anything is just plain silly IMHO as aluminum oxidises this much naturally so every airplane in the world would be illegal.
Isn't the standard in 43.13 that you can remove up to 10% of the thickness before scrapping an item? If so, why would .001 even matter?
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Re: Anyone on the forum with a NDT/Inspection background?

Post by joea » Tue Apr 12, 2011 07:49

kyleb wrote:
joea wrote:The problem is, (I feel) that the people putting up these standards have never worked out in the field. .001 of anything is just plain silly IMHO as aluminum oxidises this much naturally so every airplane in the world would be illegal.
Isn't the standard in 43.13 that you can remove up to 10% of the thickness before scrapping an item? If so, why would .001 even matter?
This is what we do not understand is that the requirements in the proposed legislation do not follow (that we can see) the "accepted means of repair" that we have been working with for years.

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Re: Anyone on the forum with a NDT/Inspection background?

Post by Aryana » Thu Apr 14, 2011 17:33

The average human hair is .004 inches.

.001 is absolutely ridiculous.
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Re: Anyone on the forum with a NDT/Inspection background?

Post by joea » Thu Apr 14, 2011 18:13

Aryana wrote:The average human hair is .004 inches.

.001 is absolutely ridiculous.
Agreed and please make sure that you comment on this legislation.

Also please save a copy of what you posted and the time and date. The people pushing this through are now saying that they never received ANY comments back in 2008 and a lot of us remember doing so.

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Re: Anyone on the forum with a NDT/Inspection background?

Post by Paul Agaliotis » Thu Apr 14, 2011 19:33

The FEDs don't engineer this stuff, they act on the information provided. They either accept or reject the proposal as written.
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Re: Anyone on the forum with a NDT/Inspection background?

Post by Classicaero » Fri Apr 29, 2011 06:34

I have done a fair amount of research in this area due to my background working the Luscombe Type certificate (all metal stressed skins with lots of corrosion potential). There is a standard for the 10% of nominal thickness, unfortunately its in a manufacturer's guideline for either Lockheed or Boeing, and relates to generally heavier (and higher stressed) skins. I am unaware of such a standard in 43.13.

FWIW, the manufacturing tolerance of aluminum is about .05%, so it may already be under nominal dims out of the box during a repair, add to that the alclad layer on structural aluminum which is .05% to .10% of the thickness, and that would seem to leave us with a useful tolerance of about 10% less than nominal thickness, but I have no engineering calcs to back that claim.

The use of a DER with some calculations of any lap joint strength showing that a 10% skin thickness degradation exceeds the strength of the riveted joint or other attachments would be the proof calculations needed for this issue. Since riveted joints rarely exceed skin shear strength of 70-75%, that proof would be pretty easy. That load information for riveted joints IS in 43.13.
Doug Combs, for Classic Aero LLC.
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Re: Anyone on the forum with a NDT/Inspection background?

Post by planemech » Thu Sep 08, 2011 23:23

I was surfing the Aeronca web sites and came upon this post. I am a Level II NDI Certified in Dye Penetrant, Eddy Current and Level I in Mag. Particle. I/A/W NAS 410. I'm an A/P and IA living in the "panhandle" of Florida. I'm also restoring a 7AC Champ. If I can be of service to the Aeronca family please contact me.

planemech747@att.net
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Re: Anyone on the forum with a NDT/Inspection background?

Post by deCreeft » Fri Apr 12, 2013 12:18

Hi Joe!
Looks like you guys are progressing towards gathering forces...
I am stuck with replacement of Angles, because Previous Owner (just as destructive as "jag previous owners") cut and spliced angles at will; a mess.
Attempting (still) to sell floats and complete Sedan Rigging *and* big prop so as to pay at least most of wing repair...
New heart valve pumping good...still dont know about flying eventually but not abandoning Sedan !! (gonna be 81 next month)should sell everything but stating with floats then certified airplane...
Bill de Creeft
Homer, Alaska
Bill de Creeft

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