What is the definition of a wet runway?

The definition of a wet runway is characterized by the condition where there is some water present on the surface, but it is not enough to be classified as contaminated. The correct choice states that a wet runway involves 25% contamination with water depth of 3 mm or less. This definition recognizes that although there is water on the runway, it does not create significant hazards typical of more heavily contaminated surfaces, such as those with standing water or ice.

This condition is crucial for pilots to understand, as it helps manage expectations about tire friction and the aircraft's braking performance. When water covers a runway, the depth and percentage of coverage can significantly impact aircraft operation during takeoff and landing.

In contrast, the other descriptions either refer to conditions that indicate more severe contamination or specify characteristics that do not accurately apply to the definition of a wet runway. For instance, deeper water or a higher percentage of contamination typically aligns with definitions of a slippery runway rather than a wet one. Understanding these distinctions is vital for safe aircraft operations under varying runway conditions.