Using mobile phones while fueling

[Lightning6]

Originally Posted by Graybeard

Typical scene: woman admits getting back in her car while it's refueling, then gets out and removes the nozzle, and the fire starts. We now have warnings at gas pumps to touch some metal part of the car before inserting or removing the nozzle.

Friction between certain insulators creates an electrostatic charge of up to 40,000 volts or more. Plastic loves to hold a charge. Plastic gas containers must be on the ground while being fueled. I recently hollered at a guy who was filling plastic gas containers while standing in the bed of his pickup with a plastic bed liner.

Same goes for refueling an aircraft from plastic containers. Everything must be brought to the same electrical potential, or ESD - a spark - will occur.



GB

Point taken, GB...Although that is the only case I've ever heard of, no such warning signs here in the UK, but, as you say, static electricity is not to be taken lightly, earthing yourself before touching a fuel line is a sensible thing to do.

L6.

[Pinkman]

Static

GB is right - its almost always static, but the path is actually to the car body filler hole not the nozzle, which is isolated (or maybe the car to you). You have to try REALLY hard because the vapour is usually above the Upper Explosive Limit. As the fuel goes in, it displaces neat vapour out (we still do not have Stage II vapour recovery at more than a few retail sites the UK).

Rainboe, theoretically yes. See http://amd.nbc.gov/library/dm/fuel_hb.pdf

There are specialist conducting plastic cans and funnels for AVGAS I am told but I dont know how available they are.

The problem is due to get worse because Sulphur levels in fuel are dropping and the industry has had some really bad loading rack fires due to low conductivity Mogas (Sulphur acts as an internal static dissipator - not sure of the mechanism).

Don't get caught out by the desert is dry - Europe is wet thing. One of the worst incidents above was in Sweden in below freezing temperatures where the air was so dry but very conducive to spark transmission. And I have had first hand experience in Johannesburg of static ignitions when I was working there.

Again you'd have to be very unlucky. But you know what Clint Eastwood said.....

Pinkman

[prettygrumman]

I think you are all on the right track with static etc. but there could also be another reason.Any transmitting device be it a cellphone or transciever not only transmits a
modulated carrier but also third seventh and mutiples thereof of harmonics. However miniscule these harmonics are, they potentially can interfere with the electronics of the
fuel delivery circuitry, and thus cause errors in fuel readings and/or pricing. Maybe I should try it at Elstree I might get full tanks for a lesser reading!!!

[cwatters]

My understanding is that a problem was first identified at petrol stations when CB radio became popular. It was nothing to do with fires, the CB messed with the fuel metering in the pump leading to people being over or under charged. I believe the petrol companies started the fire risk story to stop people deliberately trying to mess up the pump while they were upgraded ti improve immunity. The ban on CB remained "just in case" and was later extended to phones.

If there is a risk to aircraft I supect it's more likely to be due to the potential for interference with the fuel metering but I don't know how that's done on a bowser.

[Sallyann1234]

Any transmitting device be it a cellphone or transciever not only transmits a
modulated carrier but also third seventh and mutiples thereof of harmonics. However miniscule these harmonics are, they potentially can interfere with the electronics of the
fuel delivery circuitry, and thus cause errors in fuel readings and/or pricing.

If interference did occur to the fuel metering (which is very unlikely but theoretically possible) it would be due to the fundamental transmission frequency rather than the harmonics, because (a) the harmonics will be several orders of magnitude smaller and (b) the metering electronics will be less sensitive to the higher frequencies.

[E & I]

Mobile phones

Mobile phones are not banned during fuelling. They are banned in the "fuelling Zone" 6 metres radially from the refuel equipment and fuel vents. CAP 748 states they may cause a distraction and if they have an unserviceable battery there is a possibility that they may cause a spark. The CAP 748 does go on to say that there is a possibility that mobile phones may cause interference to the refuel equipment.

A few years ago a technician had a fire bottle squib on his bench when his mobile phone resyncronised itself the squib detonated on his bench.

The IATA fuel manual also provides interesting background reading.