Prist when and with what to use it
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Well, seems my memory wasn't so far wrong after all.
Its a toxic hazchem that can't legally be carried in an aircraft without a dangerous goods licence, however it is a certification requirement to use it on certain types.
You need to have done a course before you touch it and must wear a face mask or goggles, and impervious gloves, apron footware which must be washed before re-use.
The manufacturer states categorically that it MUST not be merely poured into a tank as this is more hazardous (to the aircraft) than not using it at all yet regular users seem unaware of this!
Other users seem to think it has further properties unknown to the manufacturer (ie biocide).
Users evidently ignore the health hazards mentioned above and carry - and use - it illegally and to the potential detriment of both their own health, and that of their pax.
"Justifying" illegal use and carriage is no different from claiming that you "have" to bust minima because the company expects you to and the pax "must" get to their destination.
I'm rather shocked at the cavalier attitude shown to H & S at work and hazardous goods carriage by both employers and users (pilots) here. If you get poisoned by this stuff there's only one person to blame, and it ain't your employer!
Its a toxic hazchem that can't legally be carried in an aircraft without a dangerous goods licence, however it is a certification requirement to use it on certain types.
You need to have done a course before you touch it and must wear a face mask or goggles, and impervious gloves, apron footware which must be washed before re-use.
The manufacturer states categorically that it MUST not be merely poured into a tank as this is more hazardous (to the aircraft) than not using it at all yet regular users seem unaware of this!
Other users seem to think it has further properties unknown to the manufacturer (ie biocide).
Users evidently ignore the health hazards mentioned above and carry - and use - it illegally and to the potential detriment of both their own health, and that of their pax.
"Justifying" illegal use and carriage is no different from claiming that you "have" to bust minima because the company expects you to and the pax "must" get to their destination.
I'm rather shocked at the cavalier attitude shown to H & S at work and hazardous goods carriage by both employers and users (pilots) here. If you get poisoned by this stuff there's only one person to blame, and it ain't your employer!
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Feeling I had, you'd turn up to a discussion on Prist, Moutrie Tom.
Was going to mention your extensive research - but I judged you'd arrive to tell us yourself!
The C25A AFN contains a statement from Cessna that DIEGME additive (e.g. PRIST) has provided acceptable protection from bacterial growth in fuel systems.
I have no idea whether the manufacturers are aware of Cessna's position on this - but I suspect that they probably are.
Edit
I just checked the PRIST website myself and of course they do acknowledge that their product has these properties - they just point out that the certification process is uneconomical so they haven't completed it.
Was going to mention your extensive research - but I judged you'd arrive to tell us yourself!
Originally Posted by Agaricus bisporus
Other users seem to think it has further properties unknown to the manufacturer (ie biocide).
I have no idea whether the manufacturers are aware of Cessna's position on this - but I suspect that they probably are.
Edit
I just checked the PRIST website myself and of course they do acknowledge that their product has these properties - they just point out that the certification process is uneconomical so they haven't completed it.
Last edited by JonDyer; 7th Nov 2010 at 14:02. Reason: Stung into actually pulling out the book and looking for a reference.
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Before we start throwing insults at each other, does anyone here have the rule book to hand and can verify for the non fuel heater carrying jockeys what the carry limitations are on UN1950 subclass 2.1?
Once we know the facts you can pass judgement to your heart's content.
Once we know the facts you can pass judgement to your heart's content.
I'm rather shocked at the cavalier attitude shown to H & S at work and hazardous goods carriage by both employers and users (pilots) here
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I checked the Dow Chemicals datasheet for Diethylene Glycol Monomethyl Ether, and it says nothing to confirm the (apparently widely held) view amongst pilots and refuelers that this is a deadly neuro-toxin similar to Sarin.
Just to be clear - this stuff is not made to be eaten. Neither is Jet A1, the aircraft itself, or your uniform.
The data sheet says the following about handling it: (my underlining)
Dow do not make Prist (they make DICE) - apparently Prist make Prist themselves. So I checked their datasheet to see how they advise handling it. (my underlining again)
After mentioning gloves and goggles they say this:
So what have we got?
I'm going to stick to goggles and gloves myself.
Just to be clear - this stuff is not made to be eaten. Neither is Jet A1, the aircraft itself, or your uniform.
The data sheet says the following about handling it: (my underlining)
Health Information
Eye contact with DEGME may cause slight temporary eye irritation and/or pain disproportionate to the level of irritation to the eye. Prolonged skin exposure is not likely to cause significant irritation or result in absorption of harmful amounts.
No adverse effects are anticipated from single exposure to DEGME vapor. Small amounts swallowed incidentally as a result of normal handling operations are not likely to cause injury due to its low toxicity.
Eye contact with DEGME may cause slight temporary eye irritation and/or pain disproportionate to the level of irritation to the eye. Prolonged skin exposure is not likely to cause significant irritation or result in absorption of harmful amounts.
No adverse effects are anticipated from single exposure to DEGME vapor. Small amounts swallowed incidentally as a result of normal handling operations are not likely to cause injury due to its low toxicity.
After mentioning gloves and goggles they say this:
Boots, aprons, or chemical suits should be used when necessary to prevent skin contact
- It's an irritant - it hurts a lot when it gets in your eye but it doesn't do any lasting damage.
- It's not likely that a pilot can suffer sufficient skin exposure to allow for any negative effects,
- It's biodegradeable and it's effective as a biostat but noone wants to pay the certification costs that would enable it to be advertised as such.
I'm going to stick to goggles and gloves myself.
Last edited by JonDyer; 7th Nov 2010 at 15:17.
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to return
to the original question about whether to use Prist or not to....
Guess, one can say, if it is required for your aircraft as per AFM / POH, then you have to use it..
but be advised that that is for pure fuel anti-ice reasons..
Any angi-fungal properties are not only highly in doubt..
PRIST themselves do not claim that anymore on their web-site ( and not because it would have been inconvenient or complex to certify it for that use..)
on the contrary, relying on PRIST, TOGETHER with bad fuel tank draining practices can create enormous problems..
called "apple jelly", that stuff is known to have sent FCUs south, engines have stopped or behaved erratically..
So draining the tanks everytime is of utmost importance..
even if the plane does not fly...planes "make water" in the tanks just by the temp diff between night & day..
Questions & Answers: Prist Hi-Flash
http://swri.org/4org/d03/fuellube/pe...es/03-4371.pdf
Guess, one can say, if it is required for your aircraft as per AFM / POH, then you have to use it..
but be advised that that is for pure fuel anti-ice reasons..
Any angi-fungal properties are not only highly in doubt..
PRIST themselves do not claim that anymore on their web-site ( and not because it would have been inconvenient or complex to certify it for that use..)
on the contrary, relying on PRIST, TOGETHER with bad fuel tank draining practices can create enormous problems..
called "apple jelly", that stuff is known to have sent FCUs south, engines have stopped or behaved erratically..
So draining the tanks everytime is of utmost importance..
even if the plane does not fly...planes "make water" in the tanks just by the temp diff between night & day..
Questions & Answers: Prist Hi-Flash
http://swri.org/4org/d03/fuellube/pe...es/03-4371.pdf
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Used Prist for years, as a previous poster has said it is not as dangerous as some would have us believe, there seems to be a self perpetuating myth emanating from the fuelers which is not backed up by fact and which suits their self obsessed Health and safety cultures that they have surrounded themselves in.
Yes its certainly not the sort of stuff you want splashing around and a degree of common sense should be used when handling it but you should not be frightened of using it.
For prist to work correctly it has to be dissolved or held in suspension in the fuel, aerosols work best sprayed directly into fuel flow. If you spray aerosols directly into standing fuel it just sinks to the bottom as does pouring prist. Pouring prist is designed to fill tanks that supply an agitation system that mixes fuel and prist in measured quantities,these systems can be found on fuel bowsers. Pouring prist should not be poured directly into aircraft fuel tanks it wont mix, sinks to the bottom and forms a jelly like mess in the tank.
Basically prist works by attracting water particles held in suspension in the fuel, it forms larger clumps which sink into the water catch sump, once there it can be safely drained off. It is not an anti freeze it is basically a water collector.
Yes its certainly not the sort of stuff you want splashing around and a degree of common sense should be used when handling it but you should not be frightened of using it.
For prist to work correctly it has to be dissolved or held in suspension in the fuel, aerosols work best sprayed directly into fuel flow. If you spray aerosols directly into standing fuel it just sinks to the bottom as does pouring prist. Pouring prist is designed to fill tanks that supply an agitation system that mixes fuel and prist in measured quantities,these systems can be found on fuel bowsers. Pouring prist should not be poured directly into aircraft fuel tanks it wont mix, sinks to the bottom and forms a jelly like mess in the tank.
Basically prist works by attracting water particles held in suspension in the fuel, it forms larger clumps which sink into the water catch sump, once there it can be safely drained off. It is not an anti freeze it is basically a water collector.
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DIGEME as many on here state, lowers the freezing point of the (very small amounts of) water in the fuel. It used to be advertised as a Biocide, but now the manufacturers of the said brands have admitted that it is too expensive to certify. If they don’t hold approval, then they will not advertise the property of DIEGME. Remember they are in America, the home of litigation. 
Speak to them directly on the phone and they will admit off the record this claim. It does hold bio-cidal properties.
Application of an “additive” will be declared in the AFM. If it is declared, then follow it. In the event of an insurance related incident, then this could bite you if this was not followed. I would far rather have to use the product than suffer engine flameout(s).
The pourable cans can present massive problems. The primary reason is people chuck them in, in their entirety, and then begin fuelling. The rate of mixing is vital. If it is not mixed properly, then “apple jelly” will form in the tank. This then gets sucked into the system and it will not burn. It can also therefore clog the fuel filter. On several Citations, I have been involved with un-commanded engine rollback due to clogging, (in the Hydro-mechanical fuel unit of the C550) as well as “fuel filter bypass” annunciations.
The answer is daily checking of fuel drains when flying. 
The D-ICE product produced in aerosol cans works far better. The only real issue with this is the fact the aerosol propellant could be dangerous if handled without care (exposed to piercing, excessive heat etc.) Also care is required when inserting the nozzle to avoid squirting in your eye. When using it, turn the nozzle away from yourself and the fueller.
All types must be handled with care and common sense, (unfortunately the latter being a dying attribute) All operators I have worked for have provided eye protection and gloves. If not, buy some. It is your choice what you choose to use and whether you choose to use it. 
JohnDyer: your comments are quite accurate! And very sensible.
It is vital that when DIEGME is used in the fuel, that aircraft fuel drains are drained daily. You will collect the orangey coloured apple jelly at some point.
Cessna states directly:
“In addition, to checking water in sump drains, proper blending of fuel products such as Prist® and biocide additives is equally important to monitor. Too much Prist® in poorly blended fuel can sometimes cause an “apple gel” condition to form in fuel tanks. Should an improper mixture ratio of anti-ice and biocide additives be discovered, the airplane must be defueled and then returned to service. Refer to the Chapter 12, Fuel –Servicing procedures in the applicable maintenance manual.”
An important fact to note here, is that if the aircraft is left for an extended time period, and/or is subject to large variations in temperature, then the DIEGME can come out of the fuel and settle to the bottom of the tank which can be drained off during the next pre-flight inspection. (Related to the comments made by falconer1 and MAN777)
There are refuellers at certain airports, which can over-react with the appearance from the nose locker, of fuel additive. They are taught (for some unknown reason that it is carcinogenic) and therefore you have to refuel yourself. Airports I can remember doing this at are Copenhagen, Stockholm and Exeter. Go to the product websites, learn the information, and help sensibly educate the refuellers.
I have found this has worked wonders with some airports we regularly visit.
As for airports with pre-mix, they tend in the UK to only be military, although Shell at Bournemouth provide the facility as do TAG refueling at Farnborough.
Please note under EU-OPS:
"Airworthiness and Operational Items (OPS 1.1160(b))
An approval is not required for dangerous goods which are required to be aboard the aircraft such as:
(a) Items for airworthiness or operating reasons"
This proves there is no issue carrying these products.
You can carry them onboard in a nose-locker. Many operators have done this for some 30 years now.
As you may or may not be able to tell, I have had to do a risk assessment on this before and researched it. (Still using it BTW!)
S&KP
Speak to them directly on the phone and they will admit off the record this claim. It does hold bio-cidal properties.Application of an “additive” will be declared in the AFM. If it is declared, then follow it. In the event of an insurance related incident, then this could bite you if this was not followed. I would far rather have to use the product than suffer engine flameout(s).
The pourable cans can present massive problems. The primary reason is people chuck them in, in their entirety, and then begin fuelling. The rate of mixing is vital. If it is not mixed properly, then “apple jelly” will form in the tank. This then gets sucked into the system and it will not burn. It can also therefore clog the fuel filter. On several Citations, I have been involved with un-commanded engine rollback due to clogging, (in the Hydro-mechanical fuel unit of the C550) as well as “fuel filter bypass” annunciations.
The answer is daily checking of fuel drains when flying. The D-ICE product produced in aerosol cans works far better. The only real issue with this is the fact the aerosol propellant could be dangerous if handled without care (exposed to piercing, excessive heat etc.) Also care is required when inserting the nozzle to avoid squirting in your eye. When using it, turn the nozzle away from yourself and the fueller.
All types must be handled with care and common sense, (unfortunately the latter being a dying attribute
) All operators I have worked for have provided eye protection and gloves. If not, buy some. It is your choice what you choose to use and whether you choose to use it. JohnDyer: your comments are quite accurate! And very sensible.
It is vital that when DIEGME is used in the fuel, that aircraft fuel drains are drained daily. You will collect the orangey coloured apple jelly at some point.
Cessna states directly:
“In addition, to checking water in sump drains, proper blending of fuel products such as Prist® and biocide additives is equally important to monitor. Too much Prist® in poorly blended fuel can sometimes cause an “apple gel” condition to form in fuel tanks. Should an improper mixture ratio of anti-ice and biocide additives be discovered, the airplane must be defueled and then returned to service. Refer to the Chapter 12, Fuel –Servicing procedures in the applicable maintenance manual.”
An important fact to note here, is that if the aircraft is left for an extended time period, and/or is subject to large variations in temperature, then the DIEGME can come out of the fuel and settle to the bottom of the tank which can be drained off during the next pre-flight inspection. (Related to the comments made by falconer1 and MAN777
)There are refuellers at certain airports, which can over-react with the appearance from the nose locker, of fuel additive. They are taught (for some unknown reason that it is carcinogenic) and therefore you have to refuel yourself. Airports I can remember doing this at are Copenhagen, Stockholm and Exeter. Go to the product websites, learn the information, and help sensibly educate the refuellers.
I have found this has worked wonders with some airports we regularly visit.As for airports with pre-mix, they tend in the UK to only be military, although Shell at Bournemouth provide the facility as do TAG refueling at Farnborough.
Please note under EU-OPS:
"Airworthiness and Operational Items (OPS 1.1160(b))
An approval is not required for dangerous goods which are required to be aboard the aircraft such as:
(a) Items for airworthiness or operating reasons"
This proves there is no issue carrying these products.
You can carry them onboard in a nose-locker. Many operators have done this for some 30 years now.As you may or may not be able to tell, I have had to do a risk assessment on this before and researched it. (Still using it BTW!)
S&KP
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Lots of good info here for those who have to use Prist regularly eg. drivers of the older Citations. I've used the pour-in cans before and poured it in at the same time as the fuel, but not tried to moderate the flow much, so I've learnt something. The cans do come with a pouring nozzle but its a pretty crude way of controlling the flow compared to the aerosols.
Anybody able to name other airport/fuel company combinations (UK or European) where pre-mix fuel is available ?
FGM
Anybody able to name other airport/fuel company combinations (UK or European) where pre-mix fuel is available ?
FGM
