What is the defining characteristic of trace ice?

The defining characteristic of trace ice is that ice becomes perceptible, indicating that pilots or crew may notice it under specific conditions, but it does not necessarily accumulate in harmful amounts. This level of ice formation typically suggests that while there is ice present, it is not significant enough to pose an immediate threat or require urgent action.

In aviation contexts, trace ice highlights the importance of monitoring conditions, as even slight ice can affect aircraft performance through changes in the aerodynamics and control mechanisms. While recognizing trace ice is critical for safety, it does not necessitate the same immediate response or concern as more considerable accumulations might demand. Understanding this distinction is vital for effective decision-making in flight operations, particularly regarding safety protocols and maintenance procedures related to de-icing.