Safe grounding of plastic/metal jerry cans?

S

Scott MacKie

Pre-Flight
Joined
Oct 24, 2020
Messages
97
Location
Woodstock, GA
Display Name
sbmackie
Home Airfield
KCZL Calhoun, GA
Auto fuel filling: wooden ladder, aircraft grounded wing tie down to ground attachment point on aluminum hangar, outside hangar of course, plastic filter funnel. Is this adequate for either plastic or metal 5 gallon cans? I used plastic 5 gallon cans to fill a Citabria and a Pacer in AK for three years this way. Was I flirting with disaster?

Thanks
 
I used to drop a strip of aluminum into the plastic can, right into the fuel, and ground that strip. A former student that flew in Alaska told us that at night, fuelling from plastic jerry cans, he could see the fuel flickering as it flowed in the cold.

Guys have also been hurt when their synthetic jackets rub on the wing and generate static and set off the fuel fumes. That same former student got blown off a wing that way.
 
Last edited:
Dan Thomas said:
I used to drop a strip of aluminum into the plastic can, right into the fuel, and ground that strip. A former student that flew in Alaska told us that at night, fuelling from plastic jerry cans, he could see the fuel flickering as it flowed in the cold.

Guys have also been hurt when their synthetic jackets rub on the wing and generate static and set off the fuel fumes. That asme former student got blown off a wing that way.
Click to expand...
For clarification: the aluminum strip was in the fuel can the entire fueling process? If so, while it was pouring, and I'm assuming you're standing on a ladder, how did you keep the aluminum in the spout of the fuel can? Or am I totally not getting it?
 
Grounding the aircraft doesn't matter if the supply is not grounded. I use a metal can with a wire to bond the can to the aircraft.
 
This is an older video but has some excellent teaching in it:

 
At some point, I was told that plastic fuel cans were conductive, albeit with a very high resistance. However, I've never been able to measure it.

Ron Wanttaja
 
Every week in the summer I ride around for an hour and a half on my John Deere, pull in my shed, grab a 5 gallon plastic can and top off the Deere, with a plastic nozzle into a plastic tank.

Am I, too, flirting with disaster?
 
When I enquired why the right tip was damaged ; this is the story I got.

Owner was fueling left tank with mo-gas that had been left in plastic cans in the sun.

When he noticed flames coming from the port he immediately covered the

inlet WITH HIS LEFT HAND!

He simultaneously threw the flaming can with his right hand only to have

it bounce off the right wing tip!

No ground.
 
Scott MacKie said:
For clarification: the aluminum strip was in the fuel can the entire fueling process? If so, while it was pouring, and I'm assuming you're standing on a ladder, how did you keep the aluminum in the spout of the fuel can? Or am I totally not getting it?
Click to expand...
I'd clip the strip to the nozzle with the grounding clip.
 
Todd82 said:
Every week in the summer I ride around for an hour and a half on my John Deere, pull in my shed, grab a 5 gallon plastic can and top off the Deere, with a plastic nozzle into a plastic tank.

Am I, too, flirting with disaster?
Click to expand...
jbDC9 said:
When I use plastic jerry cans to fuel my RV-8, I make sure to keep the plastic nozzle touching the filler neck... haven't blown up yet.
Click to expand...
My John Deere 1010 has a metal tank but I have never seen a farmer do any grounding in my entire life. How do they survive?
 
Snowmass said:
My John Deere 1010 has a metal tank but I have never seen a farmer do any grounding in my entire life. How do they survive?
Click to expand...
So you’re saying the proper way to prevent an explosion when welding patches on a fuel tank really IS to fill the tank with fuel? (Cuz, ya know, that’s the only way I’ve ever seen it done)

just because people do things and get away with it repeatedly doesn’t mean it’s the right way to do it.
 
Todd82 said:
Every week in the summer I ride around for an hour and a half on my John Deere, pull in my shed, grab a 5 gallon plastic can and top off the Deere, with a plastic nozzle into a plastic tank.

Am I, too, flirting with disaster?
Click to expand...

Maybe. I do the same thing. The difference is that with your and my JD, we're probably only pouring a couple of gallons at a time, so there's less opportunity to build a static charge. Also, the air (at least where I live) is very moist, so static isn't nearly as bad as on a cold dry day where there is relatively little airborne moisture.

The worst case is pouring a LOT of fuel on a very dry day.
 
jbDC9 said:
When I use plastic jerry cans to fuel my RV-8, I make sure to keep the plastic nozzle touching the filler neck... haven't blown up yet.
Click to expand...

Friends of mine were more elaborate. They ran a welding rod down into the plastic gas can, then ran a clip from the welding rod to a grounding point on the airplane, so the fuel, plastic tank, and airplane all carried roughly the same static charge.
 
Bonding the liquid isn't effective and there's no way to bond a plastic can.
 
Geez, kinda makes me wonder why we all got these auto fuel STC's. Guess it was because we hoped airport managment would install mo gas pumps next to the 100LL. Sigh.
 
Is the best option metal cans, always ground can before hitting the ladder, keep contact between spout and funnel? Does funnel material matter? Can one use some kind of pad on the wing top to place the can on while pouring? I don't hear about this happening. Anyone have direct experience with someone who blew themselves or their airplane up?
 
Scott MacKie said:
Is the best option metal cans, always ground can before hitting the ladder, keep contact between spout and funnel? Does funnel material matter? Can one use some kind of pad on the wing top to place the can on while pouring? I don't hear about this happening. Anyone have direct experience with someone who blew themselves or their airplane up?
Click to expand...
First learn the difference between bonding and grounding. They are not the same thing. Then the necessary solution will be obvious.
 
Lndwarrior said:
First learn the difference between bonding and grounding. They are not the same thing. Then the necessary solution will be obvious.
Click to expand...
OK, Einstein, I've learned the difference. Still not obvious. I apologize profusely for my lack of intellectual capability. I will now withdraw from the conversation, as obviously I do not belong in such august company as yours.
 
Scott MacKie said:
OK, Einstein, I've learned the difference. Still not obvious. I apologize profusely for my lack of intellectual capability. I will now withdraw from the conversation, as obviously I do not belong in such august company as yours.
Click to expand...
Wasn't trying to be snarky. You were using the term "ground" in the previous post which led me to believe that you were confused about an issue that frequently gets confused. You bond the gas can to the plane. You don't ground it. If you research the term "electrical bonding" then the answer to your question becomes obvious.
Im sorry if my post came across as condescending. That was not my intent.
 
Lndwarrior said:
Wasn't trying to be snarky. You were using the term "ground" in the previous post which led me to believe that you were confused about an issue that frequently gets confused. You bond the gas can to the plane. You don't ground it. If you research the term "electrical bonding" then the answer to your question becomes obvious.
Im sorry if my post came across as condescending. That was not my intent.
Click to expand...
An airplane that has recently landed can be loaded with static electricity. Tires don't drain that off well at all. In cold weather it's much worse, and if there's blowing snow it's worse yet. If you don't ground the airplane you can draw an arc when you touch the thing, or when the gas can nozzle gets close to the filler neck and you're holding the can.

Aircraft have been known to catch fire while fuelling with a thunderstorm in the vicinity. The air is full of static, and those wings act as antennae to pick up RF from lightning strikes.
 
I would encourage folks to go an view the video I posted above (post # 5). It really is educational.
 
So, for the last xx years, I've been referring to the gizmo I attach to the airplane (ususally a tie down ring), with the other end attached to a hook of some kind in the ground, as a grounding cable. That is the only thing I've used, whether refuelling from a truck, a ground based pump, or plastic cans. When using a ground based station, or a truck, that is all I've done. No bonding cables anywhere. If using cans, and I attach, a cable bew
Capt. Geoffrey Thorpe said:
Grounding the aircraft doesn't matter if the supply is not grounded. I use a metal can with a wire to bond the can to the aircraft.
Click to expand...
OK, so if I ground the aircraft via the standard grounding cable we see everywhere, ground the can before going up the ladder (put it on the ground), bond the funnel or the can to the aircraft, and start pouring, I've done what I can do?
 
Scott MacKie said:
OK, so if I ground the aircraft via the standard grounding cable we see everywhere, ground the can before going up the ladder (put it on the ground), bond the funnel or the can to the aircraft, and start pouring, I've done what I can do?
Click to expand...
Seems that way to me.
I don't ground the aircraft myself - bonding the metal can to the wing seems adequate to me.

The hose from the pump on the typical fuel station (or corner gas station) is conductive to avoid static.

Fun fact: back in the olden days ('70s '80s) when cars had miles of black rubber vacuum tubing under the hood as part of the emissions controls, you could replace spark plug or the coil wire with the hose. (yes, I did it.) There was enough carbon in it to conduct high voltage.
 
In the chem lab all flammable bulk solvents are nearly always dispensed from metal cans. Many flowing liquids in plastic containers can generate and accumulate a static charge in the container which, under certain circumstances can discharge and ignite vapors. It is not necessary to ground the aircraft. Rather, it is important that the fuel container and the aircraft are electrically connected so that they are at the same potential. Plastics are good insulators and can't really be electrically bonded to the aircraft effectively. Fueling with metal containers is certainly recommended, and satisfies the electrical potential equalization requirement readily. Fueling indoors, where fuel vapor could accumulate, is not a good idea, and is most likely in violation with fire code in most locations. I had an owner next door to me at one point that gave me the Willies storing large amounts of gasoline in the hangar, and fueling the plane from multiple plastic jugs indoors.
 
wanttaja said:
At some point, I was told that plastic fuel cans were conductive, albeit with a very high resistance. However, I've never been able to measure it.

Ron Wanttaja
Click to expand...
Everything is conductive at the right voltage! LOL.

Sometimes whole houses act like fuses. Hahaha.
 
Scott MacKie said:
So, for the last xx years, I've been referring to the gizmo I attach to the airplane (ususally a tie down ring), with the other end attached to a hook of some kind in the ground, as a grounding cable. That is the only thing I've used, whether refuelling from a truck, a ground based pump, or plastic cans. When using a ground based station, or a truck, that is all I've done. No bonding cables anywhere. If using cans, and I attach, a cable bew

OK, so if I ground the aircraft via the standard grounding cable we see everywhere, ground the can before going up the ladder (put it on the ground), bond the funnel or the can to the aircraft, and start pouring, I've done what I can do?
Click to expand...

What you want to do is connect the conductive (metal) fuel container to the aircraft with an electrically conductive connector (wire). If the fuel container and the aircraft are connected together they will have the same electrical potential, and a static discharge between the fuel container and the aircraft is impossible. This is what happens at your fuel farm. The "grounding" wire is connected to the fuel dispenser, and the fuel hose/nozzle is conductive and electrically connected to that "grounding" wire. The fuel farm may itself be grounded, but that really doesn't matter. Grounding the aircraft will only prevent electrical discharge between the aircraft and other objects also connected to and electrically at the same potential as the ground.
 
USAF was very big on the “ 3 point ground “ system.

Aircraft to ground

Fuel truck to ground

Fuel truck to aircraft.

I understand they lost a couple when it was not employed.
 
Todd82 said:
Every week in the summer I ride around for an hour and a half on my John Deere, pull in my shed, grab a 5 gallon plastic can and top off the Deere, with a plastic nozzle into a plastic tank.

Am I, too, flirting with disaster?
Click to expand...

Most modern plastic fuel containers now contain flame arrestors in the spout. This does enhance safety, as the plastic containers are more prone to flow-based static charge buildup. If you live in a very humid climate, the risk is lower. But there is some risk. The risk increases if you are dispensing a large quantity, say 5-10 gallons in one go, with no time to discharge static buildup, such as fueling an airplane from large plastic containers indoors. Topping off a 2-3 pint gas tank in a lawn mower or snowblower outdoors where fuel vapors can disperse more quickly is less likely to result in an adverse event.
 
It's more like 2 gallons a pop, I've got a pretty big yard. But maybe after reading this I'll stop doing it in the shed and do it on the driveway. Most of the summer it is "corn sweat" humid here in western Ohio.
 
MauleSkinner said:
So you’re saying the proper way to prevent an explosion when welding patches on a fuel tank really IS to fill the tank with fuel? (Cuz, ya know, that’s the only way I’ve ever seen it done)

just because people do things and get away with it repeatedly doesn’t mean it’s the right way to do it.
Click to expand...
If thousands of people do it this way no problem then it makes you think it is right. Just like grounding an aircraft. I have never done it over 70 years, Must be my ghost writing this.
 
Snowmass said:
If thousands of people do it this way no problem then it makes you think it is right. Just like grounding an aircraft. I have never done it over 70 years, Must be my ghost writing this.
Click to expand...
Accidents are quite rare.

I am reminded of one of the old man's war stories. Had a buddy that liked to show how you could throw a lit cigarette in a bucket of avgas and it would just go out. So, no big deal smoking while refueling an A-26. He got away with it right up until the day he didn't.
 
Plastic Jerry Cans are sold every where many, probably most, are are used for refueling vehicles and airplanes or my farm tractor. Do really think they would be allowed if their use would be dangerous? Can you imagine the law suits it tort America? Seriously?
 
MauleSkinner said:
So you’re saying the proper way to prevent an explosion when welding patches on a fuel tank really IS to fill the tank with fuel? (Cuz, ya know, that’s the only way I’ve ever seen it done)

just because people do things and get away with it repeatedly doesn’t mean it’s the right way to do it.
Click to expand...
I've welded hundreds of fuel tanks. Never a problem. Always almost empty. Sometimes I'll pump nitrogen in but not always. Gas tank...get it out of my shop. Don't want to see it or touch it. Have it boiled, I'll consider it. Had a customer bring a leaking tank in. They asked if we welded gas tanks. Gas no. Fuel yes. They rinsed the tank with diesel to hide the gas smell then drained. Blew up in the guys face and needed to medevac him out.
 
Last edited:
I was a pipe fitter a long time ago. The lubricated plug valves that are commonly used on small (<4") gas pipelines tend to leak if they're not lubed properly. When splicing into a line controlled by one of these valves, there were a few times my welder would just light off the open end of the pipe and weld away. It made a flare a foot or two long, and anyone nearby gave us the "you're crazy" look and give us a wide berth.

I thought about bringing a pack of hot dogs to work for an impromptu cookout, but never got around to it.

:D
 
You must log in or register to reply here.
Back
Top