Sight Tube.

[vwglenn]

OK. So what do the regs say? Can I roll without it or does it need to be there? I can see the tank by bending over or using a mirror. Or I could put a peep hole in the panel so I could see the graduation marks on the tank in flight. I honestly think that would be more effective than the tube itself.

[NWade]

OK. So what do the regs say?

As far as whether the sight-gauge is required: Flying Magazine answered this in a 2010 article/mailbag segment. I've heard this elsewhere, too (...that FAR 91.205 only applies to standard-category aircraft, not Experimentals). If you're going to fly at night or with an IFR-equipped aircraft then most people say that you become subject to more-stringent requirements, similar to what standard-category aircraft must carry for day/night VFR instrumentation.

The FAA addresses these topics in an Order about standards and requirements for the issuance of an Airworthiness Cert. See pages 127, 150, and page 169 of FAA Order 8130.2G.

Enjoy,

--Noel

[DCASonex]

I would be OK with the site tube if it registered three or four gallons. Then it would serve some panic button type purpose. To be honest though, I just don't see the point if the lowest it will register in my plane is 6. That's closer to 1/2 a tank than empty.

Thats what I realized when I had installed the as plans sight tube and started flying. I removed it simply because it provided no benefit and increased failure modes. Down the front hanging below the panel might work better, or just ducking your head under the panel to see the tank would work as well.
I use an FT60 flow transducer and my MGL xTreme fuel totalizer with great results. (However the first one lasted only 100 hours) The Princeton probe died after I used MoGas. The Belite fuel level transducer is incompatible with the MGL. I also use a timer as a backup. And a calibrated dip stick during pre-flight.

I had sight tube routed along edge of panel and down side of fuselage. gave readings for bottom of tank. BUT I removed it after two years when found tubing had gotten so hard it was brittle. It actually snapped in half when removing it. My Princeton prob has worked well connected to the GRT Sport SX, but I use only Avgas, and the red cube flow sensor into same Sport SX has also been reliable so no longer saw need for sight tube that looked to present its own hazards.

David A.

[vwglenn]

As far as whether the sight-gauge is required: Flying Magazine answered this in a 2010 article/mailbag segment. I've heard this elsewhere, too (...that FAR 91.205 only applies to standard-category aircraft, not Experimentals). If you're going to fly at night or with an IFR-equipped aircraft then most people say that you become subject to more-stringent requirements, similar to what standard-category aircraft must carry for day/night VFR instrumentation.

Although I'm a private pilot, I have no intention of flying at night and #600 certainly can't handle any real IFR. The local guys I've talked to seem to echo the same thing the article did.

I had sight tube routed along edge of panel and down side of fuselage. gave readings for bottom of tank. BUT I removed it after two years when found tubing had gotten so hard it was brittle. It actually snapped in half when removing it.

That's part of my concern as well. The tube I pulled out wasn't exactly what I would call flexible any more. Plus there are electrons flowing behind that panel and it's considered bad practice to run fuel related equipment near hot wires.

To sum up (so I can sort it out in my pee brain)...
Not required. (no night or IFR here)
Potential failure points (Leaks, brittle tube, electronics proximity)
Not accurate (only registers above 6 gallons without mods)
Still able to make visual fuel checks. (lean over or mirror)

I'm not seeing an up-side for keeping it in place.

[kmacht]

I would love to watch a video of someone trying to lean over in flight and view the fuel tank. Even better, try it with a passenger on board as well. It is hard enough to do while on the ground never mind while strapped in and flying. I suspect you will quickly find yourself in an unusual attitude.

Keith
#54

[vwglenn]

I would love to watch a video of someone trying to lean over in flight and view the fuel tank. Even better, try it with a passenger on board as well. It is hard enough to do while on the ground never mind while strapped in and flying. I suspect you will quickly find yourself in an unusual attitude.

Keith
#54

Valid point. Thanks.

I'm still leaning towards (hehe) a marked tank and a mirror or peep hole because I don't want to be in the video where my sight gauge ruptures and the plane catches fire.

I'll think about my options and at least do some tests on the ground with the engine off.

[daleandee]

*

[mike.smith]

Why you don't think it's accurate?

Well, the way mine is set up, the sight tube is only good until there are 6 gallons left in the tank. That's the point at which the fuel gets too low to read. I was always trained to never trust a fuel gauge and I've always relied more on a timer and fuel burn.

Through measuring the fuel added when calibrating the tank, my lowest point registers about 5 gallons. I have two sets of marks. Black are for gallons while sitting on level ground (I have a tail dragger), and the red marks are for level flight. I like having a simple visual reference, though I'd like a fuel flow sensor at some point. As for seeing the fuel in the tank by looking under the panel, good luck. I have red and black marks there, too, but I have never been able to actually see where the fuel is in flight. It's a long stretch of my torso to look under, and unless there is back-light (like a work light on the ground), I have never seen the fuel.

[JerryCPP]

It is a very simple matter to plumb in a small ball valve at the tank to shut off the site tube should it rupture. The weight penalty is a few grams, and it will give you the peace of mind that if there is a problem, you can shut off the flow quickly and easily. Jerry Loeffelbein, Sonex N1320X

[vwglenn]

It is a very simple matter to plumb in a small ball valve at the tank to shut off the site tube should it rupture. The weight penalty is a few grams, and it will give you the peace of mind that if there is a problem, you can shut off the flow quickly and easily. Jerry Loeffelbein, Sonex N1320X

That's a good idea.