Which statement about Type II, III, and IV fluids is correct?

• A. They are all anti-ice fluids
• B. Type II is de-ice
• C. Type III is de-ice
• D. They are not anti-ice fluids

Answer: (A)

All three fluids are designed to provide anti-ice protection on aircraft surfaces after de-icing has been performed. Their purpose is to prevent ice from reforming during the time the aircraft is on the ground before takeoff, not to remove ice that’s already there. Type II and Type IV fluids are high-viscosity anti-ice fluids that cling to the surface to extend protection, with Type IV commonly offering longer holdover times. Type III is a medium-viscosity anti-ice fluid used in specific conditions and is also intended for anti-icing, though it’s less common today. De-icing fluids, which are used to remove existing ice, are typically Type I and have shorter holdover characteristics. So, the statement that these fluids are all anti-ice fluids best captures their purpose.