What temperature range is optimal for the de-ice/anti-ice fluid during the final step of a two-phase process?

The optimal temperature range for de-ice/anti-ice fluid during the final step of a two-phase process is indeed cold. When de-ice/anti-ice fluids are applied in colder conditions, they are designed to remain effective in preventing ice accumulation. This is crucial because warm or hot fluids may not freeze effectively or could lead to improper application, which might not provide the necessary protective coatings needed during flight operations.

Using cold fluids allows them to maintain their viscosity and freezing point, ensuring that they can effectively adhere to the aircraft surfaces and perform their function of preventing ice buildup. In contrast, warmer temperatures could lead to a rapid cooling and potentially a freeze of the fluid itself on contact with colder surfaces, which may reduce the overall effectiveness of the de-icing process.

Therefore, using a cold fluid ensures that the fluid does not freeze too quickly upon application while still providing optimal protection against ice formation on critical surfaces of the aircraft.