When does the TACAN system transmit range information?

The TACAN (Tactical Air Navigation) system transmits range information specifically when it is interrogated by an aircraft. This interaction is key to how the TACAN system operates, as it relies on the aircraft sending an interrogation signal to the TACAN ground station. Once this signal is received, the TACAN station responds by providing range and bearing information to the aircraft. This method ensures that the data transmitted is relevant and tailored to the specific inquiry made by the aircraft, which is essential for accurate navigation.

In contrast, the other options suggest continuous transmission or limitations to specific phases of flight. However, TACAN is designed to transmit data in response to specific requests, making the interrogation process the correct context for when range information is provided.