Fueling Options

[jtpitkin06]

Just wondering after reading the procedures for fueling airplanes how people gas up other vehicles.

I've never used grounding cables when fueling my cars or trucks at the gas station. Don't think I've ever seen them available for cars and trucks.

I've never grounded a riding lawn mower for refueling. The lawn mower has a plastic tank and sits on rubber tires.

I use plastic fuel cans to fill up everything from weed whackers to tractors.

When purchasing fuel and filling plastic jugs the recommended procedure is to put the jug on the ground and not to fill it in the bed of the pickup. how is the plastic jug conductive sometimes and not at others?

I don't think I'm doing anything vastly different from the rest of the world but it sounds like I'm going to blow up if I'm wearing a blue sweater while fueling.

[SkySteve]

I've wondered the same thing. Why is fueling an airplane SO different from fueling anything else? Everybody I fly with hauls fuel around the desert or backcountry in either plastic jugs or Alaska Airframes rubber fuel bags, including me. Then we just either climb up on a rock or airplane tire and dump the fuel in the tank at some remote location. I have never heard of any airplane blowing up that way. What are we missing -- or not?

[SkySteve]

For what it's worth, this from a website called Experimental Aircraft Info:

"If you use a metal jerrycan with a metal or otherwise conductive funnel (Mr. Funnel), make sure the aircraft, funnel and container are touching each other during the refueling process. Any static build up is not possible then.

Metal containers dissipate the electric charge easily. Plastic containers usually not, unless they are made of conductive materials. We recommend the use of metal containers with a good jumper wire. It is so much safer."

So, the question seems to be, are plastic and rubber fuel jugs or bags required to be made of "conductive materials"? Still, everyone I know uses plastic or rubber fuel jugs or bags in the backcountry.

[Dave S]

Lowell, John & Steve....This is becoming an interesting thread. We may be on to trying to figure out what is myth and what truth.

I do like Lowell's solution to bonding the fuel filler ring without soldering....hadn't thought of that before...but if I had it to do over again....

Where does the static risk come from? Are we sure?

Like John, I use plastic cans to fuel all of my yard toys - don't seem to have any problems there.

Did some looking to see if I could find any authorative and empirical information on actual incidents....does not seem to be much on airplanes but there is some on cars. It appears static related fire incidents are pretty darn rare. I found this reference from the Petroleum Equipment Institure.

https://www.pei.org/sites/default/fi...0Incidents.pdf

They have collected 176 incident reports in 2010 and reported in the attached link above.

Who blows themselves up at gas stations? From this report, it appears to be those people who start the pump, go sit in their car to stay warm - building up a static charge on their person due to friction between their clothing and the car's interior - go back and touch the fuel filler handle and whammo.....

I don't know if there is a take away for fueling airplanes from this report but for cars it does not seem to be only the act of simply pumping gas....seems more complicated than that; and, cigarrettes, cell phones and running engines might not indicate the greatest risk although they are certainly recommended to be avoided.

Prevention might be more than one route......good bonding to dissipate a charge in the first place; and, not building up a charge; but, I wonder if a person builds up a charge on their person and then touches a well bonded system when filling? wouldn't that make a spark?

Some addittional thoughts?

Sincerely,

Dave S
KF7 TRigear

[Pilot4Life]

So, here's my two cents....because I saw it on the Internet...LOL!

Seriously, I have put Hundreds of Thousands of gallons of fuel (JET-A, JP-8, F34) into everything from generators, to helicopters (CH-46/47/53), to airplanes and jets (F-15/16/18, B-200/300/350, C-172/183)...you get the picture. In all those scenarios, the fuel system was grounded to the earth (via the tires and hoses touching the ground) and the receptacle was subsequently grounded to the fueling system (via the tires and grounding cables).

Not to mention thousands of hours conducting sling operations while both flying and serving as the load master beneath all sorts of Marine & Army helicopters...static discharge was a major danger there!

For the Internet junkies (admittedly, we can all be one at times)...There's a myth busters video on YouTube that addresses the cell phone concern at the pump. Sometimes they're goofy and you might wonder "why do people care about this particular myth?" But this one seems relevant. The long and short, after careful consideration and not-so-scientific research, is that it's is always a bonding/grounding issue. So, unless your plane is airborne (i.e. On jacks, specifically ones that have a non-conductive surface) and a person who's built up/carrying static electricity on their person, could somehow get a metal gas can to the fuel port without touching the ground or anything that's grounded out, then yes....a static discharge could ignite gasoline vapor.

Keep your wheels in contact with the ground (discharges static electricity), keep the fuel source in contact with a conductive surface that's touching the plane (Lowell's method looks good), and make sure your discharge all static electricity you might have generated when shuffling your feet on the shag carpet that we all line our hangar/garage floors with and you'll be fine. Like many have said, we use different methods to fuel different things (mowers, snow sleds, quads, etc.) but they all have one thing in common....they're all touching the ground!

Take it for what it's worth....

[SkySteve]

One additional thing I have heard and read is that the static build up mainly comes from the fuel flowing through the fuel line, i.e. the feeder hose and nozzle. Reference has been made that a car or truck does not hold enough fuel to cause much of a fuel line static to build on its own, while an airplane holds so much more fuel than a car, truck, tractor, 4 wheeler, lawn mower, etc allowing static to build in the feeder fuel line as fuel passes through it. If that is true, my little 6 gallon wing tanks should never be a problem!

[HighWing]

Definitely more than meets the eye. All good info.

[jiott]

A further thought: we are all assuming that the Kitfox fiberglass fuel tanks are totally insulated from the aircraft frame. I am not sure this is true. I know clean fiberglass is a good insulator, but maybe our tanks have some coatings or the fuel itself that allows some conductivity. The tanks touch the aluminum spars possibly thru thin spots in the silicone adhesive. The fabric and paint that touch the metal filler neck may be somewhat conductive, especially the silver UV paint with all the little aluminum particles in it. I have a strong hunch that there are many paths to ground the filler neck to the aircraft frame although none of them are real good, but probably good enough to dissipate a small static charge. Therefore, when you use the traditional grounding cable and attach it to your exhaust pipe you are actually making an adequate ground connection. This along with reasonable common sense, smoking etc., may be why there are nearly no incidents of fire.

Still leaves the question of filling with plastic jugs and no grounding cable.

[SkySteve]

This from the EAA Website: "The plastic gas cans we buy at Wal-Mart are made of a conductive plastic."
They go on to say it is important to hold the plastic gas can spout on the edge of the wing tank filler rather than hold the gas can spout in the middle of the wing tank filler, not touching any part of it. Apparently touching and holding the two while pouring fuel into the wing tank is the key. The same idea as letting the fuel nozzle rest against the fuel tank filler neck of your automobile at an auto gas station.

[n85ae]

Grumman E-2C's I worked on in the Navy would give you a heck of a shock
if they weren't grounded on occasion if you walked up and just touched one
after flight. So I totally understand the need to ground them. I've had that
with certain cars as well depending on the kind of soles my shoes had ...
Where the car would zap me.

Jeff