[pierre smith]

Guys,
This story was related to me by another RV6A builder (deceased last year) and it really needs passing along, especially to you guys close to flying your newly built airplane.

He was asked to check out a new RV 4 and to roll it around a bit. Off he went and rolled and looped and had a good old time with the owner watching on the ground. Upon looking down at the rear stick, the flyer (my buddy), noticed that the end that was inserted into the elevator pushrod (the end that the heim ball screws into) was NOT rivetted at all!! Only friction was holding it in!

This is not at all an uncommon occurence, unfortunately. You guys need to very, very carefully inspect each pushrod and control cable from one end to the other, being painfully observant. Inspect the rudder cables from the cotter key in the front to the cotter key at the rudder horn and so on. Don't count on the DAR because he could miss it too and apparently did.

If any of you guys know of other stories that we all could benefit from, kindly post them for us,
Regards,
Pierre

 

[N162RV]

Recently there was a new 7A flying at my home airport and I was looking it over just before he was about to go flying. He had around 20hrs on it by now and I noticed the cotter pin holding the elevator trim tab was there but not bent at all. Luckily it hadn't come out YET. I would hate to think what could have happened with the trim tab fluttering in the breeze.

Point is don't be bashful in TACTFULLY pointing things out that may or may not cause a problem.

 

[Kyle Boatright]

When I do the Tech Counselor thing, the three primary things I look for (at least with planes nearing completion) are:

1) Is there anything about the engine installation that will cause a reliablity issue.

2) Is the airplane properly rigged?

3) Is there control continuity?

In my mind, these are the three things that *really* matter, and are probably the items which are most likely to get someone hurt if they are not properly addressed.

On the control continuity thing, I have the owner sit in the airplane and "box" the controls - move them to the full extent of their travel. While the owner is doing this, I'm applying resistance to one control surface at a time to make sure nothing is gonna come loose. I think it was Ken Scott at Van's who wrote about a sobering instance where he had forgotten to rivet the aileron push tube fittings and one came loose when he and a helper were resistance checking the controls on his airplane.

 

[gmcjetpilot]

Who da thunk

A Gent in my EAA group before I knew him bought a flying RV-4. He just bought it and only flew it once or twice, but was now going to try some aerobatics for the first time since he bought it. Long story short: hand prop, got a way, hit a tree, one wing tank damaged, plane stopped, aircraft not damaged except for totaled tank.

Now the story: During the rebuild replacement of the tank, they found the REAR SPAR BOLT WAS MISSING. GONE, NO BOLT?

Since I have known him he's no rookie and has owned many planes before and since he bought this complete RV-4. Obviously the hand prop deal was a dumb mistake, but this guy had no reason to believe the RV was unsafe\, which appeared well built. He's a super careful guy and assumed the RV fine.

I have jumped in many "strange" RV's without inspecting the rear spar bolt or carry through first. You just assume its fine since it just flew. It's not an easy area to see. However if buying any RV, check the edge margin, rear spar connection and related structures. If flying an unknown plane you might try to at least see if the bolt's there.

The rear spar was also a source of problems in very early RV-3's. The few early failures where mostly due to builders not understanding the importance of edge margin. Van did respond by making the structure even more robust. You have to screw up badly to make the rear spar unsafe, but NO BOLT!

The good news, RV's built reasonably well, even with poor details, are still basically sound due to a good design. There of course are limits to how poor a detail can be, while still maintaining residual strength, BUT NO BOLT!

My friend was very lucky. The hand prop accident, which prompted his dis-assembly of the wing, may have saved his life.

 

[jonbakerok]

Elevator Pushrod

I met a guy at the Wharton flyin last year who was telling me about all the things he found wrong with his kit after he bought it second hand. The scariest was when he was installing the elevator pushrod, he noticed some movement in one of the rod end bearing plugs. So he drilled out the pop rivets to take a look. He found that all the pop-rivets were barely into the meat on the bearing end plug because the guy had drilled them too far from the edge of the tubing. So he drilled out the rest of the pushrods and found the same problem everywhere else. Apparently the previous builder didn't own a tape measure and didn't believe in deburring.

Can you imagine pulling back and having the stick go limp in your hand? Sends a shiver up my back just thinking about it.

 

[BrickPilot]

Can you imagine pulling back and having the stick go limp in your hand? Sends a shiver up my back just thinking about it.

I was at a recent EAA chapter meeting where an FAA inspector was giving a talk about bad engineering / assembly. Reading the above comment made me recall one of the stories he told about a Yak that crashed not to far from here. Apparently, the particular Yak had no closed bulkhead between the cockpit and the tail cone. In the crash wreckage (which showed that the Yak augered in straight down at a very high velocity), the inspector found a screwdriver wedged in the elevator bell crank. Apparently, it had fallen out of the guy's pocket during some aerobatics, made its way south and lodged in a very critical area - freezing the elevator in place in whatever attitude it was in at the moment. So, having the elevator freeze up in your hand would be just as terrifying as having it go limp. Scary stuff!