Type IV anti-icing solution is used after de-icing the aircraft surfaces.

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

Answer: (D)

After de-icing, you apply anti-icing fluid to prevent re-icing during taxi and takeoff. The holdover time, or how long the liquid remains effective, is the key consideration. Type I is used for de-icing to remove existing ice and does not stay on the surface for long protection. Anti-icing fluids come in Type II and Type IV; among them, Type IV is designed to remain effective longer, providing extended protection against re-icing. Type III is largely outdated and not commonly used today. So after de-icing, the fluid chosen to prevent re-icing is Type IV anti-icing solution.