What indicates a need for caution when dealing with frost on an aircraft's wings?

Frost on an aircraft's wings poses a significant safety concern primarily because it can trigger a stall at lower speeds. When frost accumulates on the wings, it disrupts the smooth airflow over the wing's surface, which is crucial for generating lift. This disruption can lead to a reduction in the wing's aerodynamic performance, making it more susceptible to stalling, especially during critical phases of flight such as takeoff and landing when the aircraft operates at lower speeds.

Recognizing the impact of frost on aerodynamic characteristics is crucial for maintaining safe flight operations. By understanding this, pilots can take appropriate precautions, such as ensuring that the wings are adequately de-iced or that they avoid flying when frost is present. This highlights the importance of pre-flight inspections and adherence to safety procedures to mitigate the risks associated with frost and similar hazards.