Icing Conditions

Icing Conditions exist when an aircraft encounters visible moisture (clouds, rain, drizzle) at temperatures at or below 0°C, causing supercooled water droplets to freeze on contact with aircraft surfaces.

Types of aircraft icing:

• Rime ice: Rough, opaque white ice — forms in cold clouds with small droplets
• Clear ice: Smooth, transparent ice — forms with large supercooled droplets, hardest to remove
• Mixed ice: Combination of rime and clear
• SLD (Supercooled Large Droplets): Particularly hazardous — can overwhelm de-icing systems

Icing affects lift (disrupted airflow), weight (added mass), thrust (engine icing), and control (frozen control surfaces). Aircraft must be certified for flight into known icing (FIKI) or must avoid icing conditions entirely.