Safetying RH Balance Turnbuckle

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matthewhinmann120cm
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Safetying RH Balance Turnbuckle

Post by matthewhinmann120cm »

Hello everyone, I have a rather stupid question…

How does one go about safetying the RH Aileron balance control cable end? I’m in the process of adjusting the ailerons, and when I started saftetying the turnbuckles, I realized the RH balance cable end as the AN165-32L “eye” or “pin eye” rod end… My cables and turnbuckles are old enough that they don’t have the groove for the clip, so I have to use safety wire. There is no hole or anything for me to fabricate a proper saftey. The Cessna 120 IPC tells me that the AN165-32L pin eye end is correct.

The way it was done before was wrapped around the eye end and back, but thats not acceptable in what I can find, as it would case interference and binding the aileron horn. I’ll provide a picture so you know what I’m talking about.. I’ve look at the AC43.13 and it only gives me methods with fork ends or cable eyes…

Any info would be much appreciated.

Matt
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Re: Safetying RH Balance Turnbuckle

Post by V529 »

Matt,

Not a stupid question at all. This is one of "those areas" on the airplane that require special handling. Years ago I had a tech article in the Newsletter (complete with pictures......which I can't find) concerning just this subject.

The issue as you have correctly identified is that when you pull the safety wire tight, it will slide off the eye and wedges between the eye and the bellcrank. Thus, every time you move the aileron the safety wire pushes against the aileron bellcrank stamped metal ear. Does this identify your situation?

The only real solution is to carefully wind the .041 (all major flight controls should have .041 wire on the turnbuckles) around the eye but not pull it tight. Let the wrap around the rod shank provide the tension needed to keep the turnbuckle from turning. It won't be a perfect loop, (just keep the loop more or less centered on the outside of the eye), but it does work out. Give that a try. If you have further questions, either post them here or send me a PM.

All this being said, there is a "fork" you can buy for that application, I don't have the MS or AN number for it. I did purchase one and after looking at it, decided to keep my eye and just like with the safety wire situation. Once you have it in place, there's probably seldom any need to change it.
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Re: Safetying RH Balance Turnbuckle

Post by 8342 »

Matt,

If you don't already have one you need to get a copy of AC 43.13-1B. If has a wealth of information about aircraft repairs and specifcally about how to do the saftey wiring you are asking about.
It is located in Chapter 7 Section 10. Figure 7-26 (page 7-44) has a picture of how turnbuckles are to be saftied.

The AC is downloadable from the FAA website, although I prefer a paper copy which you can get from most aircraft supply stores.

Rick
matthewhinmann120cm
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Re: Safetying RH Balance Turnbuckle

Post by matthewhinmann120cm »

Thanks for the reply. Yes, that correctly identify my situation. I will probably just keep the safety loose around the head then. I thought about the idea of buying a new turnbuckle and new AN165 that have the grooves, and just use a safety clip on one end, and safety wire on the other side. I’ll post a picture when I complete the safety.

Thanks for the input guys.
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Re: Safetying RH Balance Turnbuckle

Post by V529 »

Hi, I certainly understand the difficulty of the safety wire job at this location. I've done it numerous times. I don't know as a single clip turnbuckle is either legal or physically possible? How would you just wire one side? What would be the standard (when the AC clearly denotes how to safety wire, it doesn't have a diagram for one side). Also, how would you get a wire through the center of the turnbuckle with a clip end in there? I believe you'll just have to stick with the afore mentioned "loose loop" method.
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Re: Safetying RH Balance Turnbuckle

Post by 8342 »

Matt,

Where is your A&P? He should be able to help you with what you are trying to do.
You cannot legally do this work without the oversight of an A&P.
You say that you adjusting the cables. Do you have a cable tensiometer?
What data are you using for the adjustments?
Please ask you A&P for help. That is what we are here for.

Rick
matthewhinmann120cm
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Re: Safetying RH Balance Turnbuckle

Post by matthewhinmann120cm »

8342 wrote: Sun Feb 19, 2023 7:37 am Matt,

Where is your A&P? He should be able to help you with what you are trying to do.
You cannot legally do this work without the oversight of an A&P.
You say that you adjusting the cables. Do you have a cable tensiometer?
What data are you using for the adjustments?
Please ask you A&P for help. That is what we are here for.

Rick
I am an A&P, and I have consulted with a couple of IAs that I work with. Non of which had ever seen or experienced this safety issue before. They told me to look at the AC43.13 like I had already done… but like I already mentioned, the AC doesn’t specifically address this type of turnbuckle/rod-end setup. All the examples in the AC (including figure 7-26) show the AN170, AN161 rod ends.

It really makes me uncomfortable how the safety wire can, and will make contact with the aileron control horn. But I mean, if this is the method of safetying these for the past 76+ years, then who am I to argue :lol:
matthewhinmann120cm
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Re: Safetying RH Balance Turnbuckle

Post by matthewhinmann120cm »

Here’s a few pictures. In the 2nd picture, you can see where the old safety wire was actually chaffing on the aileron control horn… The safety wire in the pictures is only to show the path. I have yet to finish the safety.
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Re: Safetying RH Balance Turnbuckle

Post by V529 »

You're on the right road.......
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