Which of the following is NOT a required condition for visual separation authorization in non-approach control towers?

Visual separation authorization in non-approach control towers relies on specific conditions that enhance the safety and effectiveness of air traffic management. The primary responsibility of the controller is to ensure that aircraft maintain safe distances from each other, and visual observation is crucial to achieving this.

When visual separation is authorized, at least one aircraft must be visually observed by the tower, allowing the controller to ascertain its position and trajectory in relation to other aircraft. This visual observation helps the controller make real-time decisions about the spacing and separation of aircraft.

Clear weather conditions are also vital for visual separation. Poor visibility could hinder a controller's ability to visually observe aircraft, thus compromising safety.

For situations involving visual separation, both aircraft must typically be in the same area so that the controller can monitor their proximity and ensure they remain adequately separated. This is essential for maintaining effective visual oversight.

In contrast, being in radar contact is not a prerequisite for visual separation in non-approach control towers. The primary requirement is the visual observation of at least one aircraft rather than the reliance on radar tracking for separation. Therefore, radar contact is not necessary for visual separation to be established in these environments.