Fuel Sight Gauges Turning Dark

[RanRan]

I have not had any planes in the shop to change the sight gages. The company aircraft here in YKM live outside pretty much year round and while the sight gages are not as clear as new, they are definitely very usable. S/Ns 71-96, and 4-800+ hours.

Pete D.

Way back when, I developed a product with Ford Motor Company...a pvc product that had to be resistant to UV rays - the plastic turned yellow until we solved it...the problem expressed in this thread has nothing to do with UV 'aging' but, rather, the assimilation of lead from the fuel passing through the 'clear' plastic tubing. It's grey, not yellow.\

If your data is inconsistent, then I would ask, are you sure you are getting the same tubing from the same manufacturer through your distributor? Probably not, he's going to buy the cheapest 'clear' plastic tubing he can find. There are UV ratings for pvc, but is there a lead rating? Probably not.

[couleeone]

[QUOTE=**Caveat** I am not a mechanic nor aircraft owner. In fact I'm even worse...I'm the son of an IA who's never bothered to finish his A&P and still flies his dad's airplanes instead of buying one of his own. Take everything I say with with a healthy dose of "he might be full of shit".[/QUOTE]

Clay that statement made my day today! left me with a big grin!

[Pete D]

The tubing is formed, its not quite as simple as pulling it off a roll and cutting it to fit. I'm not sure how its done, but when I see them ready to go in the airplane the bends are pre-formed in them. I'm guessing its probably some kind of heat process, but I really don't know.

Pete D.

[turbopilot]

Before



After



We do need a fix for this.

[Pokette]

Clay, Clay, Clay - I for one take everything you saw as wisdom earned over all your years, (are you about 90?) Keep the insights coming.

Now that I looked mine are beginning to darken as well but still usable. The hardest thing is to see them when in direct sun - like when fueling. I have someone watch the gage while I fuel up, or vice versa...

So possible stuped a@@ question - does the fuel need to be drained to replace the sight gauge?

I have noticed that when my tanks are about 1/4 for just a little bit over the fuel is gone from the sight tube. A related question how are the markings calibrated? And if you have different tires on will that change the markings?

Thanks.

[couleeone]

Thats a good question about tundra tires and changing the site picture on the tubes? what about the 3x3 landing gear, especially when you have both? Im sure you would figure it out anyway. Come to think of it, in flight you are level so that wouldnt change just when you are on the ground....boy am I ramblin!

[Table Rock Aviation]

The sight tube guages on N743CC are starting to turn slightly dark but are definitely still useable. I have noticed that there is a slight hazy film that develops on the exterior of the sight tubes over a couple of months. I take a soft dry cloth and wipe over the tubes and it makes the tubes appear to be really clear again for a couple more months. Thats with 800+ hrs on our airplane as well.

[RanRan]

...a slight hazy film that develops on the exterior of the sight tubes...

Oxidation. I wonder if a product like Amor All would help prevent that from happening.

Didn't they use glass tubing, you know, in the old days?

[Pete D]

Yes, the old cubs (Super Cubs and J3s with wing tanks) had glass tubes. Something like 10 parts, per side. This assembly has about 4 parts per side.

Pete D.