Why is it critical to mix windshield washer fluid properly?

Mixing windshield washer fluid properly is vital primarily to avoid freezing in cold conditions. Windshield washer fluid typically contains a mixture of water and a cleaning agent, and when the temperatures drop, water alone can freeze, obstructing visibility and potentially damaging the washer system. A proper mix, usually with antifreeze properties, ensures that the fluid remains liquid, allowing for effective cleaning and visibility.

While preventing engine overheating, ensuring proper hydraulic performance, and enhancing rotor efficiency are important for an aircraft's overall operation, they are not directly related to the function of windshield washer fluid. The correct ratio helps to maintain the fluid's effectiveness across varying environmental conditions, which is crucial for safe flight operations.