When may an amateur station transmit without a control operator?

The FCC requires that every amateur radio station must have a designated control operator whenever it is transmitting. This is a fundamental rule of amateur radio to ensure continuous accountability and adherence to regulations. Many new hams confuse the concept of a control operator with local, manual control. Even when a station is operating under automatic control—such as a repeater, a beacon, or an APRS node—there is still a designated control operator legally responsible for its transmissions. Therefore, the correct answer is "Never." A station cannot legally transmit under any circumstance without a designated control operator.