Missing washers in control system

[mburch]

A non-builder friend, who has been flying his secondhand RV-8 for several years, texted me a video and a question: "Is this bolt on the bottom of the stick supposed to be loose?" With his permission, I've uploaded the video here for general awareness. Probably most people reading this can tell what's wrong just from a blurry still image:



All the washers are missing from inside the fork on the bottom of the control stick, allowing the rod end bearing on the elevator pushrod to wobble back and forth. That probably matters less than the fact that the pivot bolt has been "torqued" on essentially nothing at all, so the only thing keeping the nut from backing off is a little patch of nylon.

Needless to say, I advised the owner to study the plans and undertake a meticulous end-to-end inspection of the entire control system before further flight. No, I don't know how this was missed during the several previous condition inspections.

A good reminder to be extra fastidious about control system hardware!

 

[D-Dubya]

Washers? I don't need no stinkin' washers. Those are hard to put in that tight space.

But seriously, posts like this are a benefit to the RV community in general. As the expression goes, we often don't know what we don't know. Especially for the non-builders who may not be aware of what it's supposed to look like when it's installed correctly. Vic Syracuse is really good about sharing these real-life examples of anomalies he's found on RVs. While some of these issues won't necessarily make the plane fall out of the sky, they're certainly not "right" and can cause undue maintenance issues.

Thanks for sharing.

 

[Roadjunkie1]

Condition inspections and IA.....

We often don't know what we don't know. Especially for the non-builders who may not be aware of what it's supposed to look like when it's installed correctly.

Which begs the question about A&P/IA's not familiar with RVs doing condition inspections. Yes, common things are common but if someone doesn't know what it's supposed to look like, things can be overlooked. This is an example.

I would think someone with a Repairman's Certificate for his/her own RV could do or at least help with a condition inspection done by an A&P/IA. Of course, there might be a liability issue but also might result in safer airplanes..... Hmmmmmm....

Correction: A&P added to comment....

 

[rmarshall234]

That’s a curious comment about IAs doing CIs. I can’t imagine an IA that doesn’t understand the importance of control system connections that eliminate unwanted movement and have proper hardware stack up. But then again ( as the photo demonstrates ) not much surprises me anymore. I would think the bigger takeaway is that not everyone should be building - or flying - and that more eyes are better than less eyes.

 

[MacCool]

There are no A&P/IA's that are "familiar with RV's" within 120 miles of here. Access to RV expertise is not as ubiquitous as many people think.

I have been pleased with the A&P/IA that does my condition inspections, but I certainly don't know enough to provide him with any realistic oversight. I have given him copies of both of Vic Syracuse's books and the RV-9A construction documents, which he tells me he has found useful.

 

[Mel]

There are no IA's that are "familiar with RV's" within 120 miles of here. Access to RV expertise is not as ubiquitous as many people think.

IA not required. Only A&P required to perform condition inspection.

 

[MacCool]

IA not required. Only A&P required to perform condition inspection.

Yes, I'm aware. The previous poster mentioned IA's. My A&P also happens to be an IA.

 

[Toobuilder]

There are no A&P/IA's that are "familiar with RV's" within 120 miles of here. Access to RV expertise is not as ubiquitous as many people think...

But what "should" be ubiquitous among the certified mechanic community is how rod end bearings are to be assembled. Does not matter if its a Cessna, F-15, RV, or John Deere tractor... The same engineering principles are applicable. It is the responsibility of anyone charged with the inspection of this airplane to know that.

 

[Mike S]

But what "should" be ubiquitous among the certified mechanic community is how rod end bearings are to be assembled. Does not matter if its a Cessna, F-15, RV, or John Deere tractor... The same engineering principles are applicable. It is the responsibility of anyone charged with the inspection of this airplane to know that.

Right on Michael.

 

[MacCool]

But what "should" be ubiquitous among the certified mechanic community is how rod end bearings are to be assembled. Does not matter if its a Cessna, F-15, RV, or John Deere tractor... The same engineering principles are applicable. It is the responsibility of anyone charged with the inspection of this airplane to know that.

Agree completely, and it's the reason I that I'm OK with engaging a local A&P/IA, after appropriate vetting, despite his lack of intimate familiarity with RV's specifically. Like any profession, there are good ones, and some maybe not so good. Caveat emptor. In my case, I was encouraged by my A&P's enthusiastic willingness to review Vic Syracuse's books. We've become friends and I trust him. A good thing since RV mechanics are few and far between around here.

 

[Roadjunkie1]

A&P/AI

A good thing since RV mechanics are few and far between around here.

Just wait. Most of the graduates of A&P schools are going to the airlines. The population of GA mechanics is getting ever smaller. And, like everything, there are good ones and not so good ones. I have a friend who recently went through a notable A&P school. Started with two classes of 35 and was whittled down to one class of 22. She went to GA; most others went to The Big Boys. Would you expect someone who mostly works on King Airs/turbos be familiar with those lowly home-built airplanes..? Yes, there are standard methods of how things should be put together but how many times have we all seen something that was.....interesting.....in an RV. Not the way I would have done it but it looks ok....

The point of my post was thinking either a builder helping an A&P/AI inspect an AB/E aircraft or have the authority to be the inspector and sign off a conditional inspection. Something that may have to be considered in the future as the population of A&P/IA dwindles....

 

[gasman]

Just wait. Most of the graduates of A&P schools are going to the airlines. The population of GA mechanics is getting ever smaller. And, like everything, there are good ones and not so good ones. I have a friend who recently went through a notable A&P school. Started with two classes of 35 and was whittled down to one class of 22. She went to GA; most others went to The Big Boys. Would you expect someone who mostly works on King Airs/turbos be familiar with those lowly home-built airplanes..? Yes, there are standard methods of how things should be put together but how many times have we all seen something that was.....interesting.....in an RV. Not the way I would have done it but it looks ok....

The point of my post was thinking either a builder helping an A&P/AI inspect an AB/E aircraft or have the authority to be the inspector and sign off a conditional inspection. Something that may have to be considered in the future as the population of A&P/IA dwindles....

And that statement brings us back to part of MOSAIC in question.....
https://www.youtube.com/watch?v=GYvqGyp1sEM

 

[jrs14855]

Bolts

The OP is incorrect regarding the torque on the bolt. In that example the integrity of the bolt/nut is not compromised.
The elastic nut is not compromised.
Of course the correct spacers/washers should be used but failure to use them has no effect on bolt/nut integrity unless the bolt is tightened to the point of bending the fitting.

 

[mburch]

The OP is incorrect regarding the torque on the bolt. In that example the integrity of the bolt/nut is not compromised.
The elastic nut is not compromised.

Sorry, but I don't agree... given the obviously incorrect installation of this hardware, I assume that this very likely happened as well:

...unless the bolt is tightened to the point of bending the fitting.

Anyway, the point here is not to argue about how scary this scary control system installation is.

 

[Webb]

Sorry, but I don't agree... given the obviously incorrect installation of this hardware, I assume that this very likely happened as well:



Anyway, the point here is not to argue about how scary this scary control system installation is.

I agree with you. The rod end bearing ball should be tight and in torque with the bolt so there is no movement of the ball.

 

[PaulvS]

I agree with you. The rod end bearing ball should be tight and in torque with the bolt so there is no movement of the ball.

That is my understanding also and washers of the correct thickness would be used to fill the gap.

 

[BobTurner]

That is my understanding also and washers of the correct thickness would be used to fill the gap.

Another common failure is when washers are omitted and the nut is torqued ‘to spec’, but in fact the nut has bottomed out (run out of thread) and the bolt has no pre-load at all.

 

[JDeanda]

Worse Than Ya’ll Know

I’m an A&P, used to do a lot of work on Pitts and assorted other aerobatic airplanes. I don’t think a Pitts ever went thru our shop with the right combination of washers, bolts and nuts in the whole control system unless I’d already worked on it. And that was equally true of both factory and homebuilt Pitts, and other types. I got pretty good at putting those things right and then working with owner/pilots to rig the whole airplane to fly straight. Have only worked on a few RVs, including our own RV-6, but yeah, I see the same things going on. Vic Syracuse is right, if you look around long enough you can just about always find a loose or missing jam nut. I see engine controls mis-rigged fairly often, too. Whenever I can, I remove clevises and wire-thru-bolt connections and replace them with rod ends. Clevises seem to woggle holes out pretty fast and then the control gets a bit vague.

 

[Radioflyer]

From my point of view, the owner mentioned by the OP is an excellent example of the the way things should work. A non-builder owner carefully examining his machine sought advice from someone he knew had knowledge of that machine, A&P or not. Imagine that…a lowly non-builder finding things that others have missed over years of CIs.

 

[Phyrcooler]

And that statement brings us back to part of MOSAIC in question.....
https://www.youtube.com/watch?v=GYvqGyp1sEM

Just wait. Most of the graduates of A&P schools are going to the airlines. The population of GA mechanics is getting ever smaller. And, like everything, there are good ones and not so good ones. I have a friend who recently went through a notable A&P school. Started with two classes of 35 and was whittled down to one class of 22. She went to GA; most others went to The Big Boys. Would you expect someone who mostly works on King Airs/turbos be familiar with those lowly home-built airplanes..? Yes, there are standard methods of how things should be put together but how many times have we all seen something that was.....interesting.....in an RV. Not the way I would have done it but it looks ok....

The point of my post was thinking either a builder helping an A&P/AI inspect an AB/E aircraft or have the authority to be the inspector and sign off a conditional inspection. Something that may have to be considered in the future as the population of A&P/IA dwindles....

This thread and others support why I strongly believe we need to push to ensure that the Light Sport Repairman - Maintenance (LSR-M) and Light Sport Repairman - inspection (LSR-I) are included and expanded as a part of MOSAIC. Unlike currently wherein only the builder can get a repairman certificate for an EAB, we need the ability for any future owners to attend a class to be properly trained, and obtain this ability for any aircraft that meets the amended “Light Sport” classification. Please support this by commenting on MOSAIC during this open comment period.

 

[RV7A Flyer]

From my point of view, the owner mentioned by the OP is an excellent example of the the way things should work. A non-builder owner carefully examining his machine sought advice from someone he knew had knowledge of that machine, A&P or not. Imagine that…a lowly non-builder finding things that others have missed over years of CIs.

Except he'd been flying it "for several years", so presumably at least one other "knowledgeable" person missed this.