Type I and IV deicing fluids

[ces152]

Please refresh my memory what are the differences between these two types of fluids
Thank you

 

[skeezer]

Here is the really simple answer to that. I am sure someone will give you a more in depth one so here goes:

Type I : Red fluid that gets the ice off (de-ice)

Type IV: Really sticky green stuff that keeps the ice from coming back (anti-ice)

Like I said, someone will give a more complete answer but that is the simple one.

Peace!

Skeezer

 

[Sphincter Boy]

Type I:

Is referred to as a "Newtonian" fluid meaning that it has no resistance to stress which might cause it to flow. Any stress applied to the fluid will cause it to move immediately. Usually applied 50:50 solution in a heated condition.

Type IV:

"Non-Newtonian". Provides a greater resistance to running off the aircraft and a much longer holdover period. The stress or shear resistance of Type IV fluid is reduced when diluted with water. Type IV fluids work best when applied at a temp near freezing or at ambient temperature, at low pressure. Since it is not heated or applied under pressure, it cannot be used as a de-icing fluid. Type IV is designed to run off the wing as airspeed increased during takeoff. Its design properties are to have a clean wing without fluid or ice contamination at 100kts.

Hope this helps a little.

 

[Brother Francis]

I've been slimed!

The snow/sleet/ice will accumulate on the type IV; sometimes to an alarming depth. But due to the shearing properties of the fluid, assuming you commence the takeoff within the published holdover time, as the speed increases the relative wind will, prior to Vr, slide the fluid and the contaminants resting thereon off the trailing edges of the surfaces to which it is applied

A little unnerving to start a takeoff roll with an inch of snow on the wings, but if you are in seat 12A it is cool to watch as it slides off the back.

 

[Humblepilot]

Type IV Debate

There is a good debate within the industry on whether or not contaminants (ie snow) can be "floating" on top of Type IV prior to initiating takeoff roll. At my previous regional "floating" was accepted. At my previous major it was not. I am guessing if you asked 3-4 FAA POI's you would get two different answers.

Humble

 

[aewanabe]

Also important to note that because of the shearing properties of type IV, it cannot be used on your Baron or Duchess because you will not have a clean wing at rotation speed! (anything below 100 knots). Good luck at the interview.

 

[StaySeated]

Saturated

If you look back and see snow on top of the type IV, it has become completely saturated and is not doing you any good. Type IV (and Type II) absorb moisture (snow, freezing drizzle, light freezing rain) that would collect and freeze on your wing. The fluid can only hold a limited amount of precip and if you see anything "on top" of the fluid you need to go get deiced again (type I) and anti-iced after that. Attempting a take off with snow on top of type IV hoping it will shear off is just as foolish as taking off with snow on the wing hoping it will blow off.

 

[TurboS7]

Since you guys seem to be in the technical deice loop why does the FAA require us to use max thrust whenever deice fluid is applied. Keep in mind our FSDO is Miami. We are wrestling with this one especially in light of the Type IV fluid and viscosity design and measures.

 

[Sphincter Boy]

Since you guys seem to be in the technical deice loop why does the FAA require us to use max thrust whenever deice fluid is applied. Keep in mind our FSDO is Miami. We are wrestling with this one especially in light of the Type IV fluid and viscosity design and measures.

Our company does say anything about using max thrust when using Type IV. We do reduced thrust as often as possible as long as out ATOG's say that we can.

 

[80/20]

Max thrust whenever deice fluid is applied?
Most of the time when I de-ice, and especially two-step with type IV, the runway will have at least some contamination which should prohibit reduced thrust take-offs.

 

[TurboS7]

Our FAA are using criteria from the 60's, obviously Type IV fluid doesn't affect the aerodynamics of the aircraft and wing. It does cost $27.00 per gallon but has a great holdover time.$$$$$