Warbird Information Exchange

Just out of curiosity, with the advent of the recent wing attachment Airworthiness Directive, what are the costs of the new parts required under this AD? How many hours of labor would a reputable shop need to complete it?

Currently there is an AMOC for the upper attach angles allowing for inspection every 1000 hours after the initial 200 hour inspection. The lower angles still have the 200 hour inspection interval.

We have replaced close to two dozen attach angles on T-6s in the past year. All of these have been from intragranular corrosion and not from cracking. In fact, I do not believe that additional cracks have been found in the fleet that underwent the initial AD.

There is a long standing AD on the attach angles for corrosion. In my opinion this has been long ignored, based on amount of bad ones we have found. In my opinion, and this is based only on the ancedotal data that I have from watching my crew tear down a number of T-6s this last year, NAA had a heat treating problem. This has led to a lot of their extrusions having intragranular corrosion problems. We are finding this in the wings and center section as well.

I think there will eventually be a change in the interval for the attach angle inspection. I am not sure how I really feel about that given the amount of corrosion that has been found on the angles. Would everyone be taking such a close look at the angles if we weren't forced to do this 200 hour inspection? Before I bought Midwest Texans I was one of those who was convinced that the wing attach AD was completely overblown. After what I have seen in the last year, I am a true believer that they need to be examined carefully corrosion...as do a number of other extrusions in the airplane.

Yes, I realize there is an AD already covering the corrosion issue, but as I mentioned above in my opinion it has been largely ignored over the years. I have personally seen a number of T-6s over the years where it was obvious the wing attach angle covers hadn't been off the airplane since it was painted. The recent AD, of course, changed all that. But we have found corrosion on angles that passed the recent AD, but the corrosion issue was still not addressed.

There are no 'new' attach angles at this time. The only ones available are sixty year old NOS parts. It is a time consuming process to replace the angles.

Excellent post Tim!!!
It heartens me to see this being taken seriously.
I know a lot a T-6s in this area that had the AD pencil
whipped. I saw one that had been signed off and the
wing bands clearly hadn't been off the airplane.

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Don't touch my junk!!

Speaking from tragic experience, I too am glad to see this being taken seriously.

Tim, I hope you are coming to NWOC and will relate your experiences and opinion with this to the group. Sometimes the FAA cries wolf or is so concerned with minutia that folks don't always regard them with respect. In the old days there might be someone at FSDO that had actual experience with our type planes. No one wants to spend more money than necessary, but you've got to err on the safe side when it is a life critical matter like a wing attach.

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Bill Greenwood
Spitfire N308WK

I know someone who did a gound up on thier airworthy T-6 some years ago. The only significant corrosion found was on the center section lower spar cap. Unless the fuel tank stress doors had been removed it NEVER would have been seen until the screws fell out. I second Tim's suggestion of poor heat treating being a major issue, not fatigue cracks. I guess the unintended consequences of this inspection may have turned out for the best.

When this AD first came out, I talked to the FAA rep that was over seeing it. He did not care what those in the field had to say over what they have found, he knew what was best and there was no changing his mind. I have been maintaining and restoring T-6s for the last 15+ yrs and never have found a cracked attach angle, but I have found corroded ones, and there is all ready a AD that covers that.
On the alternate means of compliance the letter that came out changed the compliance time, but did not authorize any other means beside the flouesent dye penatrant, yet when you call him, he says eddy current inspection is ok. go figure.

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Matt Gunsch, A&P, IA, Warbird maint and restorations
Jack, You have Debauched my sloth !!!!!!
We tried voting with the Ballot box, When do we start voting from the Ammo box, and am I allowed only one vote ?
Check out the Ercoupe Discussion Group on facebook

Matt, I'm glad that you've never found one. However, they do exist, as my best friend's death proves.........

Sorry, I'm still a little bitter over that........

Great Articles on T-6's in

WARBIRD DIGEST Goes Racing!

Steve

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"Any excuse is good enough if you're willing to use it!"

Matt
Yes they wrote the AD with only flouesent dye penatrant but the day after i recieved the AD i filed for an AMOC using eddy current and had it approved in about two weeks. i still have that AMOC and can do that inspection here on the west coast. That is why if you call him he will tell you that eddy current is OK. I know that a couple other NDI firms applied for the eddy current AMOC and it was approved for them also

So why are there no new angles out there, only NOS? Surely in this day of high tech and materials, there should be someone making better pieces for this purpose.

Thanks,

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"There are old pilots and bold pilots but few old, bold pilots."

There has not been a demand for them. The only time they needed to be replaced was because of corrosion or a belly landing.

So then, with the AD none are needed to be replaced or is there adequate stock available? If you find one bad do you repalce all or just as needed?

What is the highest demand part with the least availability for T-6's?

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"There are old pilots and bold pilots but few old, bold pilots."

Replace as needed. As far as other parts, Prop blades, Cams, and crankshafts,

You can buy newly manufactured blades now so they are not rare, only expensive!