Grounding for fuel

linuxjim

linuxjim

Pre-takeoff checklist
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JJ
I was on a cross country recently and a guy in a c152 pulls up to the pump to get some fuel after me. I finish up and hang up the pump. I then disconnect the ground and offer it to him. He says "no thanks," grabs the pump and fills it up.

Having experience with only a few aircraft, one being a 152 in training, this surprised me and it is probably just my inexperience. So I'm curious. Under what conditions does a plane not need to be grounded?
 
Bonding is the more correct description. Most of us bond the plane to the fuel dispenser with a separate wire but likely the fuel hose is also bonded so some guys count on that.
 
Stewartb said:
Bonding is the more correct description. Most of us bond the plane to the fuel dispenser with a separate wire but likely the fuel hose is also bonded so some guys count on that.
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Personally, I wouldn't.

My industry has had a large number of devastating fires that start with fuel transfer and not bonding/grounding the containers. (typically a dismounted fuel tank being drained into the larger holding container).
 
I'd move my plane quickly and let him proceed. Free country and all.

No one knows, or can predict what the electrical delta is between the plane and the hose nozzle. Maybe it's nothing, or so small as to be not a factor. Far and away most times that's the case. But not grounding the plane is one way to find out if it's enough to jump the space from the nozzle to the filler neck. Really bad location to have a spark.
 
FWIW, for better then 20 years I've had a 100 gallon avgas tank in my truck and use it to transfer fuel to my planes using a FlowRite 12v pump mounted on the tank. I have a separate bonding wire but the filler hose is bonded so I rarely use the bonding wire. I'm more versed than most on the dangers of static spark fires and am more careful than most when fueling my planes. I have no concerns about doing this with my own equipment but when I use a self-serve fuel place I always use the bonding wire that's provided since I can't validate their filler is bonded by looking at it.
 
I wouldn't exactly move my plane away if someone else did it, but for the 4 seconds it takes and zero cost, why not clip the bonding wire on :dunno:
 
I did watch a guy hop in and start his Cessna with the wire still clipped to the pipe at St Johns AZ once. I gave him the cut signal across the throat, and he tiled his head and tossed up his hands like 'WTF?'. I just shook my head and left. As I was taxiing away, he shut down and got out and found it. No thank you on unicomm of course.
 
Ok now I'm curious as you guys are talking about the nozzle being bonded.

How does that prevent a spark? I was under the impression that the danger was a difference in charge between the aircraft frame and ground... thus a spark in the filler hole when the nozzle got close. How does bonding...grounding...whatever the nozzle to I assume the pump/tank prevent that?
 
It has been several years since I recall hashing this over here.
In past threads, we discussed:
-how many refueling fires have occurred without bonding (I can't recall the answer)
-comparison to auto refueling where we never use a bonding wire
 
So..... you pull up to a self-serve avgas place and the bonding cable clamp has fallen off or been cut off. Do you add fuel or go on your way without? That isn't just a hypothetical question. My local self-serve place had that condition more than once this year. What would you do?
 
AggieMike88 said:
Personally, I wouldn't.

My industry has had a large number of devastating fires that start with fuel transfer and not bonding/grounding the containers. (typically a dismounted fuel tank being drained into the larger holding container).
Click to expand...

Plus 100!

One of our guys almost cost us the hangar defueling one. If our airport hadn't had foam we'd have been toast. As happened, we bought the customer a new plane.
 
Let'sgoflying! said:
It has been several years since I recall hashing this over here.
In past threads, we discussed:
-how many refueling fires have occurred without bonding (I can't recall the answer)
-comparison to auto refueling where we never use a bonding wire
Click to expand...

I have three pilot friends who've had static fires during airplane fueling and have learned a great deal about static risk from a fourth guy I met along the way.
 
cowman said:
Ok now I'm curious as you guys are talking about the nozzle being bonded.

How does that prevent a spark? I was under the impression that the danger was a difference in charge between the aircraft frame and ground... thus a spark in the filler hole when the nozzle got close. How does bonding...grounding...whatever the nozzle to I assume the pump/tank prevent that?
Click to expand...

Static is created by the fuel moving through the hose or worse, by dropping out of the filler and falling through the air into the tank. The initial equalization of static potential is not a total solution.
 
docmirror said:
I did watch a guy hop in and start his Cessna with the wire still clipped to the pipe at St Johns AZ once. I gave him the cut signal across the throat, and he tiled his head and tossed up his hands like 'WTF?'. I just shook my head and left. As I was taxiing away, he shut down and got out and found it. No thank you on unicomm of course.
Click to expand...

That guy epitomizes the term "flying *******."

Rich
 
Stewartb said:
So..... you pull up to a self-serve avgas place and the bonding cable clamp has fallen off or been cut off. Do you add fuel or go on your way without? That isn't just a hypothetical question. My local self-serve place had that condition more than once this year. What would you do?
Click to expand...

Meh

I've also know folks who will touch their hand and and the nozzle to some metal on the plane, not sure of that does much.

Didn't mythbusters do a thing on this, as I recall they had to make quite the static generating machine to get the thing to light off.

Possible yes, probable no so much.
 
James331 said:
I wouldn't exactly move my plane away if someone else did it, but for the 4 seconds it takes and zero cost, why not clip the bonding wire on :dunno:
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MAKG1 said:
Exactly.

Cost/benefit. Cost is near zero. Benefit is not risking a fire.
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Maybe he'd been trying to sell his plane and couldn't get a buyer....
 
James331 said:
I wouldn't exactly move my plane away if someone else did it, but for the 4 seconds it takes and zero cost, why not clip the bonding wire on :dunno:
Click to expand...

Exactly! Why not use it? I used to be very nervous , standing in the front seat of my Stearman , pouring Amoco hi test into the tank. You also see people at gas stations, put the hose in the tank, let it fill by itself, slide into the car, usually to BS on their phone , then SLIDE back out and grab the filler handle . Real dumb. Usually a young girl.
 
Jimmy cooper said:
Exactly! Why not use it? I used to be very nervous , standing in the front seat of my Stearman , pouring Amoco hi test into the tank. You also see people at gas stations, put the hose in the tank, let it fill by itself, slide into the car, usually to BS on their phone , then SLIDE back out and grab the filler handle . Real dumb. Usually a young girl.
Click to expand...

This may be true, I'd still bet you're way more likley to crash/explode in a collision pulling in or out of the driveway of the gas station.
 
Most recent vehicles have restricted filler openings. One of the benefits is these limit air exchange and keep the air inside the tank at very rich vapor concentrations. Too rich to burn. Comparing cars in gas stations to fueling airplanes is apples and oranges.

As for the cashmere comments? Go flying in winter with polar fleece and nylon clothes and fill your plane with a plastic fuel jug. I can't imagine a better static maker.
 
Probably a good idea to bond it, and like mentioned earlier, it only takes a minute to do. It reminds me of a funny story. Shortly after I got my ticket, I joined a flying club with a private strip. I went to fuel up the plane one morning and forgot to attach the ground cable. There were two guys working on the stairs to the fuel pump. They got miffed with me and waved the cable at me. It was my mistake, but I then noticed that one of them was smoking a cigarette and the other was operating power tools while standing next to the fuel tank holding the ground cable. Maybe I should have run away ducking for cover.
 
cowman said:
Ok now I'm curious as you guys are talking about the nozzle being bonded.

How does that prevent a spark? I was under the impression that the danger was a difference in charge between the aircraft frame and ground... thus a spark in the filler hole when the nozzle got close. How does bonding...grounding...whatever the nozzle to I assume the pump/tank prevent that?
Click to expand...

No, you are wrong. Falling fuel will create a potential difference between the place it is falling from to where it is falling to. The hose is conductive and the "grounding wire" is bonded electrically to the hose as well.

Unlike car fueling where you jam the nozzle in the filler neck, a lot of planes are not filled this way. I would not rely on the casual contact of the nozzle to the filler neck.
 
flyingron said:
No, you are wrong. Falling fuel will create a potential difference between the place it is falling from to where it is falling to. The hose is conductive and the "grounding wire" is bonded electrically to the hose as well.

Unlike car fueling where you jam the nozzle in the filler neck, a lot of planes are not filled this way. I would not rely on the casual contact of the nozzle to the filler neck.
Click to expand...

The thing is that there won't be a combustible environment near the nozzle once fueling has started...a pessimist assumes there is nothing but air above the fuel in the tank and a realist knows there exists vaporized fuel above the liquid fuel in the tank. Connect the bonding wire, put the nozzle down in the tank, pull the trigger and all will be well.
 
Clark1961 said:
The thing is that there won't be a combustible environment near the nozzle once fueling has started...a pessimist assumes there is nothing but air above the fuel in the tank and a realist knows there exists vaporized fuel above the liquid fuel in the tank. Connect the bonding wire, put the nozzle down in the tank, pull the trigger and all will be well.
Click to expand...

Correct. Bonding is important, not because you're "grounding" the aircraft but you're bonding the aircraft to the filling hose.

I know of two personal friends who have had airplanes destroyed during defueling accidents which is a similar process but it's less likely to find people connecting bonding wires. Falling fuel can make sufficient static to cause ignition. Your best bet is to not have the fuel falling through the air, second best...keep everything bonded.
 
There is a reason the airlines (and others) ground plane to ground, truck to same ground, and then the fuel hose has a grounding cable that plugs into the plane before the quick fill hose is attached.
 
BillTIZ said:
There is a reason the airlines (and others) ground plane to ground, truck to same ground, and then the fuel hose has a grounding cable that plugs into the plane before the quick fill hose is attached.
Click to expand...

I would think moving hundreds of gallons of fuel has the potential to generate more static electricity than tens of gallons.
 
flyingron said:
I know of two personal friends who have had airplanes destroyed during defueling accidents which is a similar process but it's less likely to find people connecting bonding wires. Falling fuel can make sufficient static to cause ignition. Your best bet is to not have the fuel falling through the air, second best...keep everything bonded.
Click to expand...

De-fueling is unlike fueling since the fuel is likely not going into a container that is already full of fuel vapors. As the fuel starts vaporizing in the container the percentage of fuel vapor will reach the combustible range and then all it needs is a spark.

While fueling, the only place which can reach the combustible range is right at the filler neck.
 
cowman said:
Ok now I'm curious as you guys are talking about the nozzle being bonded.

How does that prevent a spark? I was under the impression that the danger was a difference in charge between the aircraft frame and ground... thus a spark in the filler hole when the nozzle got close. How does bonding...grounding...whatever the nozzle to I assume the pump/tank prevent that?
Click to expand...

Biggest build-up concern is aircraft that have just landed --- having built up a charge during the flight --- particularly those aircraft without static wicks. And most times, strap use is a CYA than an actual threat

All other times (like fresh from morning parking) is no more of a concern than it is putting gas into your car. (How many times do you connect a grounding strap to your car when you fill up?)
 
student pilot here, no idea what you guys are talking about, apparently there is some sort of ground/bond wire used when filling airplanes, hmm, interesting. FBO always fills the rental so I've never seen it done.

I always thought the static ignition risk when filling cars was an urban myth. Wasn't there a mythbusters episode about that?

So, it seems airplane refueling is a different ballgame based on the amounts transferred and static buildup from flying. I guess I learned something today.
 
jimbilly said:
I always thought the static ignition risk when filling cars was an urban myth. Wasn't there a mythbusters episode about that?
Click to expand...
There may have been a mythbusters episode. But there have also been quite a few actual fires.

But, yes, there is typically a wire on a wind up reel with a spring clip on the end.
 
Make sure you fuel a plane in your CFI's presence to learn how to fuel correctly. Although the risk is low, it isn't zero. Learn the proper way to bond/ground your plane when fueling.

On one of my solo x-c's, I was required to refuel by my CFI's solo x-c endorsement. Might as well learn how before you do this!
 
Capt. Geoffrey Thorpe said:
There may have been a mythbusters episode. But there have also been quite a few actual fires.

But, yes, there is typically a wire on a wind up reel with a spring clip on the end.
Click to expand...

What do you clip it to on the airplane?


(yes, definitely something to go over with CFI)
 
Lots of partial comprehension and misinformation in this thread. Most of us get away with less than perfect procedures. That doesn't mean we're safe as much as lucky. one rule I use myself? Nobody can be in the plane when it's being fueled.

I've posted this link before and some will take shots at it because it's old. The science is still the science. This is a good video that was handed to me by a guy with a crapload of airline and GA hours in Alaska. The fourth guy I mentioned earlier.
https://www.youtube.com/watch?v=cUs0ix10SoY
 
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