Chapter 5 - Ground Crew Supplement

Fluid Description

13.  Aircraft deicing/anti-icing fluids consist of four types. They are Type I, II, III, and IV. The various types all have different physical and chemical properties and their use is aircraft specific.

14.  Deicing fluids are typically ethylene glycol, diethylene glycol or propylene glycol based fluids containing water, corrosion inhibitors, wetting agents and dye. These fluids are formulated to assist in removing ice, snow and frost from the exterior surfaces of aircraft. They also provide a short period of anti-icing protection.

15.  Anti-icing fluids are similar in composition except that they also contain polymeric thickeners. They are formulated to prevent formation of unabsorbed frozen contamination for a longer period of time than deicing fluids; however, the protection is still for a limited period of time.

Note:  It is the heat contained by the Type l (de-ice) fluid and the hydraulic pressure (high pressure spray) that removes the frozen contaminants. The glycol provides some protection during precipitation conditions until Type ll, III or IV fluid is applied.