Prist
 

What is Prist???
For you fractional guys, when do u take on Prist when refueling?

It's a Anti-Icing Fuel additive...It's premixed most of the time with the fuel, but in the old days I've had to have it added from the fueling nozzel...Cheers

Prist is an additive to fuel that keeps ice from building in fuel lines. Somtimes fuel contains water that you cant see. When the plane climbs the temperature drops and the fuel cannot hold water. This water can separate out and could be a bad thing if it freezes in fuel lines blocking the flow of fuel and then there goes your engine.

Prist is also Anti-microbial agent. Therefore it helps to keep sludge from forming in the fuel systems. This is important if the airplane rarely flys. We fly our aircraft Mon-Fri, so it is not sitting for very long, so we very seldom add it. Many times it is already pre-mixed, so it is not an option.

TG

So why do they always ask if you want it or not? If its that good wouldn't you think it would already be mixed in all the time?

Because it makes your fuel more expensive by about $.03 per gallon.

And prist (fuel system icing inhibitor for a generic term) is the chemical Diethylene Glycol Monomethyl Ether.

Aircraft such as ours, Excel, have fuel heaters so prist is not needed for anti-icing. Other aircraft, such as the Beechjet 400 do not have fuel heaters, so they need prist.

Prist
 

+ it is poisonous as hell, and eats away your tanks if you have rubber or plastic tanks.
So oil to fuel heaters are the way to go, plus the use of new jetfuel.

It is also a anti-microbial agent; it kills the little organisms that grown in jet fuel. It is not longer labeled as such because the manufacturers of prist did not want to do the studies to meet FDA approval for such a label.

Actually, what it does is suspend water in the fuel in small enough droplets that it can't effect the performance of the fuel.