What action is required if holdover time has been exceeded?

When holdover time has been exceeded, it is essential to perform a pre-takeoff contamination check. This check ensures that the aircraft's wings and critical surfaces are free of any ice, snow, or frost that may have formed after de-icing or anti-icing treatment. Holdover time refers to the duration during which anti-icing fluids remain effective in preventing ice formation on the aircraft surfaces. Once this time has elapsed, the effectiveness of the fluids diminishes, and there is a risk of contamination, which can significantly affect the aerodynamics and safety of the flight.

By conducting a pre-takeoff contamination check, pilots can verify that no hazardous conditions are present, ensuring that the aircraft is safe for takeoff. This is crucial for maintaining safety in operations, particularly in adverse weather conditions. Other actions, such as proceeding to takeoff immediately or waiting for weather to improve, do not address the immediate requirement to ensure the aircraft’s readiness for safe flight following the excess holdover time. Notifying emergency services may be appropriate in certain critical situations, but it is not a necessary response to the exceeding of holdover time.