What is the minimum time required to apply wing anti-ice if slats cannot be visually inspected for ice?

The minimum time required to apply wing anti-ice when slats cannot be visually inspected for ice is indeed 5 minutes. This protocol is crucial because in-flight ice accumulation on the wings and slats can significantly impact the aircraft's performance, particularly concerning lift and stall characteristics.

In situations where visual inspection is not possible, the aircraft's operating procedures require a conservative approach to ensure safety. The 5-minute duration is established based on standard best practices to allow enough time for the anti-ice system to effectively operate and mitigate any ice buildup. This duration helps ensure that the wing surfaces are adequately treated to prevent the aircraft from experiencing any potential aerodynamic issues that ice can cause, thereby maintaining safe flight operations.

Understanding the procedures regarding ice conditions is vital for pilots, as ice accumulation can lead to increased drag, reduced lift, and control issues. Thus, adhering to the 5-minute standard is part of a comprehensive safety protocol aimed at preventing ice-related mishaps during flight when visual indicators are not available.