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