Icing
Structural and induction icing can quietly rob an aircraft of lift, thrust, and control, making it one of the most dangerous and frequently tested weather hazards on the Aviation Weather knowledge exam. The ACS expects you to recognize the atmospheric conditions that produce each icing type, interpret PIREPs and AIRMETs that report icing intensity, and understand why certain temperature ranges and moisture combinations are especially threatening. Work through our 6 in-depth, ACS-aligned icing articles below, or return to the Aviation Weather library.
Supercooled Water and Why Structural Icing Forms
Supercooled water droplets remain liquid well below 0 °C and instantly freeze on contact with an airframe, producing rime, clear, or mixed structural ice that can devastate aerodynamic performance.
Rime, Clear, and Mixed Ice: Identifying Structural Icing Types
Rime, clear, and mixed ice form when supercooled water droplets strike an airframe below 0 °C; each type has distinct appearance, formation conditions, and hazard level that every IFR-rated pilot must recognize.
Supercooled Large Droplets (SLD) and Freezing Drizzle Icing
Supercooled Large Droplets (SLD) — found in freezing drizzle and freezing rain — are among the most dangerous icing threats because they flow aft beyond deicing equipment, forming lumpy, uneven ice that can severely disrupt aerodynamics across a wide span of the airfoil.
Icing in Stratiform, Cumuliform, and Frontal Clouds
Icing risk, type, and severity differ dramatically depending on whether you are flying through stratiform, cumuliform, or frontal clouds — understanding these differences is essential for safe flight planning and in-flight decision-making.
Induction and Carburetor Icing: Engine Icing Explained
Carburetor icing can form even on warm, clear days and may completely shut off engine airflow; learn the temperature-humidity conditions, recognition signs, and proper use of carb heat to stay safe.
Icing Hazards: Performance Loss, Control Effects, and Tailplane Stall
Structural ice—rime, clear, and mixed—forms when supercooled water droplets strike an airframe, degrading lift, increasing drag, and potentially triggering a tailplane stall; understanding ice types, SLD hazards, and the conditions that favor each is essential for safe flight.
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Articles are original summaries grounded in the public-domain FAA handbooks and cite their source. ACS-aligned study aids — not a substitute for the official handbooks or regulations.