What must an aircraft that is not equipped with required position lights do at sunset?

An aircraft that is not equipped with the required position lights must terminate its flight immediately at sunset because these lights are crucial for visibility and safety during nighttime operations. Position lights help make the aircraft visible to other pilots, which is vital for avoiding collisions and ensuring safe navigation in low-light conditions. Without these lights, the risk of an accident significantly increases. Therefore, to comply with regulations and ensure safety, the aircraft must stop flying until it can operate within the requirements, which includes being properly equipped with functioning position lights before it can resume night operations.