Which fluid is designed as a de-icing fluid?

• A. Type II anti-icing fluid
• B. Type III anti-icing fluid
• C. Type IV anti-icing solution
• D. Type I de-icing fluid

Answer: (D)

De-icing fluids are built for rapid ice removal, so they are formulated with lower viscosity to spread quickly, break ice bonds, and wash ice and snow off the aircraft surface. Type I is the low-viscosity fluid used specifically to de-ice, melt ice, and clear the surface for safe operation. In contrast, the higher-viscosity fluids Type II, III, and IV are designed to stay on the surface longer to prevent refreezing, providing an anti-icing protective layer for a period of time. So the fluid designed for de-icing is Type I.