What is the primary composition of Type I de-icing fluid?

Type I de-icing fluid is primarily composed of propylene glycol or ethylene glycol combined with a significant amount of water. These glycol-based fluids are effective in lowering the freezing point of water, which allows them to prevent ice formation on aircraft surfaces. When sprayed on, the heated fluid melts any ice or snow present and helps keep the aircraft surfaces clean during the de-icing process.

Propylene glycol is often preferred because it is less toxic compared to ethylene glycol, making it a safer option for both the environment and human health, while still maintaining effectiveness. The mixture's properties allow it to flow and adhere well to surfaces, ensuring thorough coverage and efficacy in de-icing procedures. The inclusion of water in the composition serves to enhance the fluid’s freezing point depression capabilities while providing the necessary fluidity for application.