Anti Icing Additive for fuel system

[CT2kflyer]

A Pilatus PC-12 (N128CM) crashed in Butte, Mont.on March 22, 2009 killing all aboard. The NTSB blamed the pilot for not using a required anti-icing additive in the fuel system, which led to a weight and balance destabilization, lost of control, and the deaths of 13 family members.

 

Being fully aware that the FDCT is a totally different aircraft, with a different fuel, engine, and fuel type, I am wondering if there is an icing hazard with winter flying of my CT2k? My aircraft is sitting in an unheated hanger, fueled with MOGAS or 100LL, not getting a lot of air-time. My engine does not incorporate CARB Heat in it's systems, and was designed to operate without CARB heat.

 

So, do I have cause to be concerned for safety of flight issues if I fly it from say, Lincoln, NE to Longmont, CO in late January? The odds of flying at below freezing temps is probably near 100%.

 

Thanks.............

[Jim Meade]

The Pilatus uses a turbine engine and jet fuel. It was determined that it should have had Prist added.

 

"In the late 1950’s, as more jet aircraft were flying to higher and higher altitudes for longer times, problems started to develop with ice crystals forming in Jet fuel.

 

Fuel System Icing Inhibitors were introduced to military aviation fuels in the early 1960’s after the crash of a B-52 in 1958 attributed to ice in the fuel causing five (5) of the eight (8) engines to fail due to fuel starvation.

 

It was quickly discerned that as a hydrocarbon fuel, such as Jet Fuel is cooled, one (1) part per million of water comes out of solution from entrained water to free water. As dissolved water in fuel becomes FREE water when the fuel is cooled, it can form solids (ice) in freezing temperatures. Obviously, as the water temperature falls and changes into ice, these ice crystals can inhibit fuel flow and can possibly starve the engine for fuel.

 

For this reason, some aircraft utilize fuel heating systems to melt any ice that forms at altitude, while other aircraft require the Fuel System Icing Inhibitor (FSII) additive, PRIST® Hi-Flash™ to ensure safe flight.

 

Initially, Prist® was an Ethylene Glycol compound delivered blue in color but in the mid 90’s, was changed to PRIST® Hi-Flash™, a clear DiEthylene Glycol to offer an improved higher flash point and reduced hazardous and toxic characteristics."

 

The above is for general information and does not address your question. In my experience, we only worried about adding Prist when we were flying above 28K, and actually more likely in the mid-30's. Different operators have different standards on this.

 

 

 

 

 

[Roger Lee]

Hi CT2K,

 

You should be able to fly during the winter anytime you want. There are many Ct's flying in below freezing weather, actually below zero weather. You don't want to take off with the wings or stab covered in ice, other that that it should be a pretty flight with snow on the ground.

[chanik]

Ironically diesel/jet fuel has extremely low water absorption, lower than gasoline, which is why the problem went undetected for years. Any dissolved water is insignificant. However diesel is much thicker than gasoline and like a light vegetable oil which burns like diesel and can replace it as a fuel, the stuff forms water emulsions quite well (think salad dressing) which only gradually separate and like to clump up as microscopic ice crystals merge together in injectors and fuel filter screens. It is the pumping of the fuel with water from the storage tank that mixes everything up and makes for deadly possibilities. Gasoline emulsions separate out much faster and anyway the additives like ethanol will hold copious amounts of water harmlessly in solution. It is why Jet fuel users are taught to check the opacity of their fuel. Any haziness belies the presense of microscopic water droplets scattering the light, again just like oil and vinegar salad dressing.

[CT2kflyer]

Many thanks for your expertise...... I appreciate the information.