De-icing and Anti-icing

Types of Fluids

• Type I
• minimum 80% glycol
• relatively low viscosity
• very limited anti-icing protection against re-freezing but does not protect against further accumulation
• Type II
• minimum 50% glycol
• high viscosity
• effective anti-icing
• for aircraft with Vr > 100 kts; shears off on take-off
• potential to lose effectiveness if improperly applied
• Type III
• properties between Type I and Type II
• for aircraft with Vr < 100 kts
• Type IV
• same fluid specifications as Type II, but longer holdover times
• dyed green to aid consistent application

Holdover Time

• the estimated time that the application of de-icing/anti-icing fluid will prevent the formation of frost, ice, or the accumulation of snow on treated surfaces of an aircraft
• begins when the final application of de-icing/anti-icing fluid commences, and expires when the fluid loses its effectiveness