Airline Transport Pilot Test 2025 – 400 Free Practice Questions to Pass the Exam

Frost significantly alters an aircraft's aerodynamic properties, leading to earlier stalling tendencies. When frost forms on an aircraft's wings and control surfaces, it disrupts the smooth airflow that is essential for maintaining lift. This rough surface changes the characteristics of the airflow over the wing, causing the airflow to separate sooner than it would on a clean, smooth surface.

As a result, the critical angle of attack—at which the aircraft can no longer maintain level flight—can be reached at lower angles, causing the aircraft to stall at a higher angle of attack than normal. Therefore, pilots may experience stalls at airspeeds that would otherwise be safe, which can lead to dangerous situations, especially in critical phases of flight such as takeoff and landing. Notably, the presence of frost does not make the aircraft more stable or have no effect; rather, it degrades performance, making it vital for pilots to conduct thorough pre-flight inspections to ensure the aircraft surfaces are free from frost and ice.