Chafing can kill you

[mikelupo]

Dear Builders,
Please take chafing serious. During condition inspection, we are finding things that are darn scary. Scat tube, left unfettered can cut deep into softer metals.

The links below are to photos in my google drive. All photos are from my recently purchased RV-10.

The Fuel line chafing is inside the cabin "tunnel". Meaning, in the cabin with the pilot and passengers. The scat tube is what supplies cabin heat to the rear seats and it's unsupported and chafing into the fuel line. This is an in-flight hazard as you could end up with fuel leaking into the cabin area and possibly igniting. This would likely not be survivable in the air.

Fuel Line Chafing


These two photos are fore of the firewall in the engine compartment. The scat tube was chafing into the oil cooler. It goes without saying the bad things that could happen from a catastrophic oil leak.
Oil Cooler Chafing 1

Oil Cooler Chafing 2

[Ron B.]

Just changed out one of my heater SCAT hoses on my 14. A hose clamp had poked a hole. Rotated the clamp so the tail would not make contact and dabbed
silicone between both parts to make sure.
You have to look for some of these problems, move the SCAT and look under.

[Toobuilder]

Thanks for the reminder. Many of us have been in aerospace for decades and learned long ago these seemingly "obvious" lessons. Its apparent that with the success of Van's kits and the constant influx of new builders, these lessons need to be relearned over and over again. Every aiplane I've inspected in the last 20 years has at least one either "obvious" safety fail or a "contrary to normal practice" installation. The most egregious being the main battery cable zip tied directly to the RH fuel line of my RV-8. This fuel line was UPSTREAM of the fuel selector, and located UNDER MY LEGS at the spar center section. The battery cable, zip tie, and fuel line ALL showed signs of chafing on each other. A leak, arc, and resulting uncontrolled fuel flow feeding a fire under my legs is too horrible to even consider - yet the previous owner BUILT THE AIRPLANE LIKE THIS!

THINK, People!

[wcalvert]

Steel Scat tube wire vs. Aluminum with grit and vibration thrown in... tonight at Ten

[rv8ch]

Originally Posted by Toobuilder

Thanks for the reminder. Many of us have been in aerospace for decades and learned long ago these seemingly "obvious" lessons. Its apparent that with the success of Van's kits and the constant influx of new builders, these lessons need to be relearned over and over again. ...

I think you are right. I spend a lot of time on this site, reading whatever books I can find, webinars, other youtube videos, NTSB, etc. I really enjoy it, and I feel like I'm learning a lot. However, this is a massive investment in time that I realize most people don't have. Even still, I'm learning "do it wrong and you die" stuff all the time.

From what I have seen, the RV-14 kit is doing a great job of making it easier and easier for inexperienced builders to do it the right way. The the instructions are excellent, and from what I hear, the kit itself is also excellent.

I think that Van's is on the right track - make it easier to do it the right way rather than the wrong way. Teaching every builder 20+ years of aerospace "tribal knowledge" is much harder.

[agent4573]

Sorry these are so small, but here's what happens if a braided oil line chafes your engine mount.

>>From the Moderator: Just tap or click the image thumbnail and it’ll open in larger living color in a separate tab.<<

[Roadjunkie1]

"I built this airplane; NO ONE knows it better than I do...." Yes, well, that may be true. But did you do everything correctly? Your DAR may have picked up a few things but there may be other things lurking unnoticed. Sometimes it's a good thing to have someone accompany you (an A&P or IA or other builder you trust) on your Conditional Inspection. They might see things you have seen for so long they look OK to you. You're not the builder? All the more reason to have someone look at the airplane. Not all IA's are familiar with experimental aircraft and someone who has built an RV already may be a better choice.

I have inspected other aircraft, some flying and some ready to fly and found things that make my eyes get big! I have seen things in airplanes in various stages of being built (one by an A&P from an airline) that were not quite right.

LOOK at things with a critical eye. If it doesn't look exactly right, it probably isn't. This is something that is suspending your butt in the AIR, for crying out loud........!!!

[Foghorn]

Just so we're all on the same sheet of music it's Condition Inspection not conditional Inspection.

I'm about to have the fuselage complete, engine to tail feathers. Once done I'll invite my EAA chapter to have a hangar visit and look at everything for an extra set of eyes. I'm sure they'll find something.

[bruceh]

We found this bit of SCAT tubing rubbing up against a heat shield on Josh's RV-9A during an inspection last week.



The tubing was up tight against the heat shield and the only real visible indication was the black coloration where it had rubbed.

[Paul K]

I’m a little shocked that anyone would have anything unsupported and allowed to come into contact with anything else FWF or anyplace else on the entire airplane! I’m serious!!!!! This is a pet peeve of mine and when other builders or owners have their cowls open, I’m right in there showing them potential problems. I’m not bashful about it and most appreciate it. Sorry, this stuff scares the heck out of me!

Conversely, I invite anyone who is around when my cowl is open to look around for anything I may have missed. I tell them not to hold anything back.