Refuelling and Cell-Phone Use

[TheShadow]

I have a query about this from a Squadron Safety Officer in a South American Country's Air Force (see below). Supposedly he's to give a safety lecture and this is one topic that he's got to cover.

I know that radios are used extensively around refueling airplanes but have always been told that you shouldn’t transmit whilst being refueled yourself. Because a mobile cell-phone isn’t connected to the airplane I don’t see any threat. Pumping out high power from a radiating aircraft radio antenna might be a measurably greater hazard (particularly HF couplers) – but probably only because of the relays that are clicking over – not because of the level of radiated RF energy.

Relevant Pprune URL below about forthcoming ability to allow pax to utilize their cellphones onboard (i.e. how will you then stop pax from doing it during refueling on an operational stop?). Also point out that there’s a difference from using a cell-phone when inside (versus outside) the Faraday Cage of the fuselage.

http://www.pprune.org/forums/showthread.php?threadid=145650&perpage=15&pagenumber=1

Wouldst appreciate any input on this. I'd like to help this chap out but certainly not with any duff gen based upon my limited knowledge of the subject.

My name is Lieutenant XXXXX, from XXXXXXX Air Force. I'm preparing a presentation about aviation safety. I need to know about the refueling aircraft and the use of celular phone, if somebody is using it near of refueling operation. Why Is this a dangerous procedure? Is there some accident already occurred, or some report about this. I'm greatful for your attencion and help. Thank you.

[nosefirsteverytime]

Alright, here's my understanding of the problem. While I have no experience whatsoever of aviation refuelling, and I may get reactions of "well duh!", I have grown up behind the till of a petrol station, and at least understand the theory of no phones allowed around refuelling of cars.

The problem is this: an empty fuel tank is full of fume-carrying air, so when the tank is opened and fuel starts pouring in, this air has to be ventilated. I don't know what you use to get the air out, whether there's a seperate vent for these fumes or if they come out the hole the nozzle is inserted, but either way you get these fumes that are highly flammable expelled at some point around the aircraft. That's why there's no smoking anywhere near any refuelling. not because of the actual fuel, but the fumes coming from it.

A small aside. We once had "neighbours" the other side opf the village, and these people one day, as you did in those days, decided to burn some newspapers. Coming out into the garden I smelt the burning, and fluttering in front of me as a charred peice of burning paper. My father saw it too, and immediately went to the police. Normally no one'd take a blind bit of notice, but had that gone the other side of the house, and fluttered over to someone filling petrol, WHOOOOOOM!

You can't allow anything to ignite those fumes, and that means paper burning, cigarettes, or the electrical circuitry of a mobile phone (which on some components can get very hot). I wasn't sure about how radio waves can/can't ignite fuel, but anything with electrical components has the potential to be a fire-starter. just one spark and it's lights up.

How's that? I hope I'm not stabbing in the dark here.

[TheShadow]

nosefirsteverytime

Agree with all your comments as far as petrol goes (i.e. AVGAS) but wide-cut kerosene-based fuels with a much higher flash-point should be that much harder to ignite (except at high ambient temperatures within the confined space of a heated centre wing tank).
There are always high heat souces around a ramp, all the way from tanker and tug engines to GPU's. There is also much RF. The heated components within a cell-phone wouldn't add too much.

this Air Force Safety Center memorandum from a Google cached copy of www.aetc.randolph.af.mil/se2/torch/back/2003/0303/torchtalk.htm

“There is a lot of discussion, but very little hard data, on cell phones as potential ignition sources at service stations and other areas where flammable vapors may be present, such as aircraft refueling operations. At this time, cell phone manufacturers don’t test or certify their products for use in flammable atmospheres, so they won’t say they are safe to use while servicing vehicles. In the absence of testing/certification data, we must assume a cell phone is a potential ignition source and not suitable for use where flammable vapors are present.

“Air Force policy for any work around flammable and combustible liquids is that wherever vapors may be present, precautions shall be taken to prevent ignition by eliminating or controlling the sources of ignition. ... (In line with guidance, ‘General Operation and Inspection of Installed Fuel Storage and Dispensing Systems’ will soon incorporate a placard requirement warning operators against using cell phones while refueling at vehicle service stations).

“For aircraft servicing, cell phones should not be used within the distances listed below, unless otherwise specified in the appropriate technical order or guidance for the particular operation.

Within 50 feet of any pressurized aircraft fuel or oxygen service components
Within 25 feet of any aircraft fuel vent outlet during fuel transfer
Within 10 feet of any aircraft fuel vent outlet — unless the cell phone is intrinsically safe

“While most discussion centers on restricting cell phone use during aircraft and vehicle fuel service operations, the restriction also extends to other operations such as using gaseous or liquid oxygen, paint shops, battery charging areas and photo labs, to name a few. All operations, whether Air Force or contractor, where cell phones are used should be carefully examined to determine if any flammable vapors or oxidizers may be present.

“When more conclusive information on cell phones becomes available, we will re-evaluate the need for additional guidance. Until then, unless there is data indicating that cell phones can safely be used around flammable and/or oxidizing materials, they should not be used in those areas.”
More guidance can be found here http://www.exxonmobilaviation.com/AviationGlobal/Files/FuellingGuide2003.pdf The Exxon Mobil Aviation Fuelling Guide 2003 at page 11 states: "Allow no open fires, lighted cigarettes, matches, mobile phones and other non-intrinsically safe electrical equipment in the vicinity of fuelling operations and storage areas."

We would also refer you to http://www.pprune.org/forums/showthread.php?s=&threadid=145851 & http://www.pprune.org/forums/showthread.php?threadid=145650&perpage=15&pagenumber=1

[ukeng]

From what I can figure it's more the risk of a spark generated if you were to drop the phone rather than radiated energy.
Cell phones (mobiles) are fairly flimsy normally and dropping one from waist height normally has the battery bouncing about on the floor.
It's a miniscule risk but it's the old adage of 'never say never'.
There's a ban on using them at petrol stations over here for much the same reasons....

Personally I notice people get more distracted jibbering into their cell phone than they do using a radio - wierd ain't it!

[ferrydude]

There is absolutely no evidence that mere use of a cell phone can cause fuel vapor ignition while refueling. A big urban myth. As mentioned in a previous post, the only hazard presented by the cell phone is if it were dropped. The real hazard is from static electricity. See http://www.pei.org

[Smeagol]

Shadow

As one who has worked in the oil & gas industry for some considerable time I hope I can contribute constructively. The subject is covered extensively by a number of standards. One of the most comprehensive is:

Institute of Petroleum, Model Code of Safe Practice - Part 15, Area Classification Code for Petroleum Installations.

There are others by BS, API etc, but IP part 15 is widely used.

As the title suggests it is primarily for use in the petroleum industry and covers Tankage, Bulk Loading/Unloading, Petroleum Jetties, Distribution & Marketing facilities as well as offshore installations and drilling operations. Aircraft fuelling is not specifically addressed (as it is undoubtedly covered by some specific publication) but no doubt can be treated in a similar manner.

Basically, the code provides a guide for the classification of areas around equipment handling or storing flammable petroleum fluids in order to provide a basis for the correct selection of electrical equipment.

Strictly speaking it applies to FIXED equipment but application to 'hand held' equipment is relevant.

In order to operate a mobile phone safely in a hazardous area it would have to certified 'intrinsically safe' ie where any sparking that may occur is incapable of causing ignition of any gas or vapour present. (Identification of the 'hazardous area' is what the code is for and depends on numerous factors)

To my knowledge no manufacturer has yet produced such a phone.

Many manufacturers have published information saying their products are safe for use near refuelling operations but none appear to have actually produced a CERTIFIED piece of equipment. No doubt because it is a costly process and they do not see any return on the investment required.

As has been stated by other posters the type of fuel (fluid category) has a major affect on the area classification, kerosene types requiring less onerous measures than more volotile fuels.

Bottom line?

Do not allow the use of mobiles, if only because allowing their use around one type of fuel could lead to complacency and lead to their use in a potentially dangerous situation.

[yakker]

If mobile phones are dangerous, then a suitable experiment could be carried out to prove it once and for all. Just maybe its an urban myth.
Our airfield has a sign asking you not to use a mobile phone while refuelling, but the ground staff use transceivers, whats the difference?

[Blacksheep]

Its not actually an issue of mobile phones, its a matter of any and all electronic and electrical equipment. The use of any device should be prohibited unless it is certified as intrinsically safe. For anyone who still thinks it woiuld be safe to use a mobile phone while refuelling, would you carry your mobile phone while doing work in a fuel tank? Where do you draw the line?

[ferrydude]

following that logic, I suppose we should also remove our battery powered watches, hearing aids, and also disconnect the vehicles battery when refueling until all have been proven intrinsically safe.

[glum]

I think it's more to do with the fact a transmitting device has the potential to induce current flow in another object. If that object has a spark gap to earth, and the induced current is high enough, a spark will jump the gap. Bang.

At least, that's what I was taught on my RF radiation safety course earlier this year...

[ontrackfor]

Having worked at gas stations and apron bowzers, I like to pay attention to ignition source issues. While I'm not aware of the issues surrounding normal radiation from cellphones, I worry when they are in use, in oft clumsy hands around any refuelling area.

My understanding is that as long as the cellphone is switched on, there is a potential difference between the battery and the phone itself. Not a big deal when the battery nodes are in contact with the nodes of the phone itself but when the two are seperated, a momentary arc occurs. Seeing as fumes tend to sink and phone-battery seperation often occurs after being dropped onto the ground, this gives a coinsidence of spare voltage and fuel vapour. Perfect grounds to ban their usage around refuelling areas.

Guess this could apply to any portable electric device but cellphones are the most 'accessable' and are therefore most likely to be dropped.

From time to time I see people talking on their phones in refuelling areas on aprons and wonder at their suitablilty for this field.

[clmax]

Not really the correct experiment for the subject at hand but saw a very strange but interesting demonstration the other day on telly where they tried to see if a 100 ringing cell phones placed on top of an egg would boil it. Didnt do a thing. :hmm:

[Raggyman]

I always thought it was related to the fact that the phone is pumping out alot of RF energy.

I remember being shown how a light bulb, with two wires, one pointing up, and the other pointing down (i.e one wire connected to the + and - on the bulb) then held near a transmitting CB aerial. Quiet amazing how the bright the bulb got.

A bit more tuning of the wires soon showed how much energy was being pumped out of the CB. Put it this way, wouldn't like that much potential between something that is grounded and something that isn't, and just enough space and vapour.

It is quiet and Interesting experiment.

[Cyclic Hotline]

Check it out. Snopes. (http://www.snopes.com/autos/hazards/gasvapor.asp)

[Saintsman]

Refuelling seems safe enough but what about using mobiles near aircraft with detonators (ejection seats, fire bottles etc). Is that just as safe or are we now looking at induced voltages in cables rather than sparks?

[LuckandNeat]

The new CAP748 states that no PED's ( Portable Electronic Devices ) are to be used with in a refuelling zone.

This includes all electronic equipment but as a refueller I know that flight crews, even though they are aware of refuelling, still transmit their radios to gain clearence or weather before departure ...

I have been a refueller for quite a few years now and dont really see that a 3 volt battery from a cell phone is going to ignite fumes when there is a very hot exhaust pipe from the refuelling vehicle with in the refuelling zone !

All contradicts really and I think all is trying to be on the safe side !

I had a conversation about using PED's with in this situation with one of the big fuel companies, no names, but he too said its all the govening bodies being too over cautious ! :rolleyes: