If an aircraft sees the airport or runway, but NOT the preceding aircraft, what type of separation must be maintained for a clearance?

The correct choice relates to the separation requirements when an aircraft can see the airport or runway but does not have visual contact with the aircraft in front of it. In such a scenario, visual separation cannot be established, as the pilot is unable to maintain visual awareness of the preceding aircraft's position. Consequently, radar separation is necessary to ensure safe distances are maintained.

Radar separation allows air traffic controllers to use technology to track the positions and movements of aircraft. They can provide directions based on the aircraft's radar data, facilitating appropriate spacing. This method of separation enables controllers to ensure that the two planes are at a safe distance from one another without relying on visual contact, which is critical when one aircraft lacks awareness of the other's position while still being cleared to approach the airport.

Using visual separation only applies when both aircraft are in sight of each other, which is not the case here. Therefore, the requirement for radar separation becomes essential when only one aircraft has visual contact, ensuring safety and compliance with air traffic management protocols.