What are the two common types of de-icing fluids used?

The correct answer is based on the common classifications of de-icing fluids used in aviation. Type I and Type IV fluids are the most widely recognized categories.

Type I de-icing fluids are heated and typically used to remove ice and snow from the aircraft surfaces. They have a low viscosity and ensure that all contaminations are removed before takeoff, providing a clear surface for the aircraft to operate safely.

Type IV de-icing fluids, on the other hand, are designed for anti-icing purposes. They are more viscous than Type I fluids and provide longer protection against ice accumulation once the aircraft is clean and clear of contaminants. This is crucial for maintaining safe aircraft performance during flight in icy conditions.

Type II and Type III fluids, although used, are not as common as Type I and Type IV. Therefore, identifying Type I and Type IV as the correct de-icing fluids aligns with standard industry practices for ensuring aircraft safety and efficiency in winter weather conditions.