Fuselage strut fitting - FAA Airworthiness Concern Sheet (merged)

[adrozell]

Re: Fuselage strut fitting - FAA Airworthiness Concern Sheet (merged)

Now if we can just get that approved. But we do not have much time before the NDT portion of the AD must be complied with. Got to love FAA speed, knee jerk reaction then snail speed. I am contemplating new struts just to get rid of the repetitive inspection. I do not like the idea of pulling struts on and off. There is more chance of braking something if you slip up.

[N96337]

Re: Fuselage strut fitting - FAA Airworthiness Concern Sheet (merged)

It looks to me like x-ray could do both the fitting and the strut at the same time, still on the aircraft...look at Bill's pics on the other thread... now THAT would be nice!
JH

[adrozell]

Re: Fuselage strut fitting - FAA Airworthiness Concern Sheet (merged)

My next question is how long ago was the fuselage panted. And is there some way to prevent moister buildup in this area. For aircraft that have been recently rebuilt this would seem unnecessary, unless going the NDT rout. But this will be cost prohibitive for most. My ship has new fabric and new epoxy primer cote I hate to take that off. If this becomes repetitive like the strut AD the insulation of an inspection panel might be are best solution. Redoing good fabric will get old quick.

[Forrest Barber]

Re: Fuselage strut fitting - FAA Airworthiness Concern Sheet (merged)

I and many others agree that he failed strut attach point on the Wiley ship seems to be self evident, however , I have photos with the left wing off for another repair not too long ago that shows the fabric & paint seems to be very good shape, this other mess was under the fabric & paint.
I believe that a common sense inspection of that area will determine the airworthiness of the ship. If anything is suspect then we move on to plan B and X-Ray seems to be emerging as the answer...

[Ragwing nut]

Re: Fuselage strut fitting - FAA Airworthiness Concern Sheet (merged)

In that broken fitting picture it looks like it might have a coarse threaded bolt holding the strut on.

Or is that my eyes?

Dave

It is just the picture blown up so big, that is an AN bolt with an elastic stop nut

Mike

[adrozell]

Re: Fuselage strut fitting - FAA Airworthiness Concern Sheet (merged)

This looks like some one should have done some corrosion prevention. I spend most of my time on annual taking care of chipped pant and the such. If this had been done that none of this would be necessary. If people would do a GVI of there ship it would prevent things like this. While it may be cheaper in the short term to over look the little stuff look at all the trouble it has caused.

Re: Fuselage strut fitting - FAA Airworthiness Concern Sheet (merged)

In that broken fitting picture it looks like it might have a coarse threaded bolt holding the strut on.

Or is that my eyes?

Dave

Re: Fuselage strut fitting - FAA Airworthiness Concern Sheet (merged)

Something isn't right with that failure. I can't from that pic exactly, but it should not have failed in that manner.

It looks to me like there is a weld seam in the fore-aft direction right at the point where the strut engagement slots end.

As if the fitting had been welded back together or a crack was welded up.

Or is it me?

When I look at the new fitting there is no seam there.

Dave

[N95334]

Re: Fuselage strut fitting - FAA Airworthiness Concern Sheet (merged)

Oh I forgot the important part. The lower tubing was in the tail at the tail post, no where near the wing struts.

[Robert Lees]

Re: Fuselage strut fitting - FAA Airworthiness Concern Sheet (merged)

Don't forget that float operations also cause greater stress concentrations on fuselage fittings than land operations....water at 50mph is like concrete, whereas land operations have bungees & tyres to absorb shock.

That's why the original fitting crack AD (back in God-knows-when) was quite sensibly restricted to floatplane operations.

Rob

[DannyDot]

Re: Fuselage strut fitting - FAA Airworthiness Concern Sheet (merged)

I just sent this email to the FAA engineer, Andrew McAnaul, [email protected]. The more I think about it -- based mainly on how bad the corrosion in the failed fitting was -- the less I think we need to remove paint and fabric to make sure our planes are not like the failed plane.

As soon as I post this, I am headed to my plane to remove the seat, clean the dust away, scrape with a pointed object and look for corrosion. I am certain if my plane is like the failed plane, this simple inspection will find the problem. I will not find a crack this way, but it looks to me like LOTS of corrosion was the failure mechanism of the plane that went down.

Danny Deger

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
I have talked to you a couple of times on the phone, mainly about the strut AD. I live close to Houston and had no trouble finding an eddy current inspector and I have completed the AD. I just had an idea for people out "in the middle of nowhere". Take off the strut and turn it end over end and listen for loose corrosion rattling around. If no noise, the strut is good for another two years. Anything rattling around would mean the wall thickness must be measured.

I am writing today about the fuselage fitting concern. I am not going to fly at all until I do an inspection that is good enough for me. Looking at the photos of the failed fitting, it looked to be a "corroded mess". If this is the case, I don't see the need for removing paint and fabric for a close look. You told me on the phone during our first conversation, the corrosion was covered with paint. My look at the failed part makes me believe the corrosion was evident without removing paint and if covered, scrapping with something like the end of a screw driver would have revealed the corrosion underneath -- paint over rust comes off if scraped. Is this a reasonable description of the failed fitting?

Or was the failure primarily a propagated crack. If this is the case, a look at the area for massive corrosion is obviously not going to be adequate. Even if a crack was the "straw the broke the camels back", it looks to me the primary reason for failure was massive corrosion that should be simple to inspect for.

Last question is the affect of being on floats. First of all float operations is going to have a lot of moisture -- but being stored outside allows for moisture in the form of rain. Even more importantly maybe the way moisture drains when on floats. I have heard many places a Taylorcraft tends to corrode at the bottom of the very end of the tail because water drains to this point. While on floats this is not the case. Water will tend to drain to the fuselage fitting area because this is the lowest point. If this is the case, are non-float planes at risk for the extreme corrosion apparent in the failed plane.

Thank you for you consideration in this matter. I want to do what is safe for my plane. Like I said, I am going to do some type of inspection before my next flight. But I don't want to perform an expensive inspection to look for cracks if the failure was massive corrosion that might have been the direct result of float operations causing water to pool in this area.

[Ragwing nut]

Re: Fuselage strut fitting - FAA Airworthiness Concern Sheet (merged)

Something isn't right with that failure. I can't from that pic exactly, but it should not have failed in that manner.

[Ragwing nut]

Re: Fuselage strut fitting - FAA Airworthiness Concern Sheet (merged)

For what it is worth, My 1946 Taylorcraft BC12D had to have the lower tubing replaced in 1981 due to rust. That is the lowest point of the tail dragger.
Question, If I clip the wings, does that make my Taylorcraft expermintal and in doing so the AD does not apply?

Previously type certified parts even if in experimental class still need to comply to some level, because the same issue/promblem still exists. Read FAR Part 39.

Mike

Re: Fuselage strut fitting - FAA Airworthiness Concern Sheet (merged)

ya know, I just realized, this whole set of events is making me grumpy

[DannyDot]

Re: Fuselage strut fitting - FAA Airworthiness Concern Sheet (merged)

The Taylorcraft Service Letter 102 is here (200kb pdf)

Thank you for this link. What does this group think of this inspection? Is it too much for a non-float plane? At least it looks like you guys not close to a major airport can do this without any expensive (and not available everywhere) NDT equipment.

Keep in mind the FAA pretty much said "comply with the strut SB" on the strut AD. They may be inclined to put out an AD that says "comply with the fitting Service Letter".

Danny Deger