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Which two conditions must exist at the same time for structural icing to occur?

Choices

  • ✓ Visible moisture and a temperature at or below freezingcorrect

    Structural ice needs both visible moisture and a freezing or below-freezing surface temperature.

  • High density altitude and low humidity

    Those conditions relate to performance, not icing.

  • Strong sunshine and dry air

    Dry air lacks the visible moisture needed to form ice.

  • Unstable air and high visibility

    Instability and visibility do not by themselves cause structural icing.

Why

Structural icing requires visible moisture (clouds or precipitation) and an aircraft surface temperature at or below freezing occurring together.

FAA source: Aviation Weather Handbook FAA-H-8083-28 / PHAK Ch. 12browse the reference library →

This is taught in Weather Hazards: Thunderstorms and Icing — study the lessons free, then practice with grading and mastery tracking.

Original study question written for this course — representative of FAA knowledge-test topics, not an actual current FAA exam question.

Which two conditions must exist at the same time for structural icing… · PPL Free Ground School