Which statement about anti-icing holdover time (HOT) is true?

The statement regarding holdover time (HOT) being advisory and requiring a pre-takeoff check highlights the importance of safety and accuracy in flight operations, particularly in winter weather conditions. HOT refers to the estimated time during which anti-icing fluids applied to the aircraft remain effective in preventing the accumulation of ice on critical surfaces, such as wings and control surfaces.

By emphasizing that HOT is advisory, it underlines the fact that while these times provide useful guidance, they are not absolute guarantees. Factors such as changes in weather conditions (e.g., temperature drops or varying precipitation rates) can affect the efficiency of the anti-icing fluid over time. As a result, the necessity for a pre-takeoff check becomes critical. This check involves assessing the current weather conditions and the effectiveness of the de-icing process completed before takeoff. The pilots must ensure that the aircraft is still safe to operate, taking into account any changes since the application of the anti-icing fluid.

This understanding reinforces an essential aspect of aviation safety protocols in icy or snowy conditions, ensuring that pilots are making well-informed decisions based on the latest conditions rather than solely relying on pre-determined holdover times.