When should de-icing procedures be re-evaluated?

De-icing procedures should be re-evaluated when there are changes in weather conditions because these changes can significantly impact the effectiveness of the de-icing process. Factors such as temperature, precipitation type, and wind can all alter the accumulation of ice or snow on the aircraft, affecting its performance and safety. By continuously monitoring and reassessing the de-icing procedures in response to weather changes, ground crews can ensure that the aircraft is properly protected against any adverse conditions before takeoff.

In contrast, waiting until the end of the day or after every application of de-icing fluid may not provide an accurate response to immediate weather changes that could necessitate adjustments. Additionally, re-evaluating when the aircraft lands does not take into account the potentially hazardous conditions that could develop before the aircraft is cleared for departure, which is critical for maintaining safety during the takeoff phase.