Type I anti-ice/de-ice fluid is characterized by which of the following?

• A. Low viscosity, unthickened, short-term protection; orange color.
• B. High viscosity, long-term protection; blue color.
• C. Contains polymer thickening agent; clear/white.
• D. Intended for slow aircraft; yellow color.

Answer: (A)

Type I is a thin, low-viscosity glycol fluid used mainly for de-icing. The key idea is speed: its low viscosity means it spreads quickly over ice, helps remove it, and provides only short-term protection before takeoff. It’s unthickened, so it won’t remain on the surface for long. The orange color is a defining cue that helps crews identify the fluid visually. In contrast, fluids used for longer holdover times contain a polymer thickener, are much more viscous, and are associated with anti-icing rather than rapid de-icing (often colored differently). The other descriptions describe these thicker, polymer-enhanced fluids or colors not associated with Type I, which is why they don’t fit.