What does the FAULT light on the IDG indicate?

The FAULT light on the Integrated Drive Generator (IDG) indicates that a fault has occurred within the IDG itself. This warning is crucial because the IDG, which is responsible for converting variable engine speed into stable electrical power for the aircraft, must function correctly to ensure reliable power generation. When the FAULT light illuminates, it serves as a signal to the flight crew that there may be something wrong with the generator, potentially affecting the electrical distribution system on the aircraft.

In this scenario, identifying the nature of the fault is essential for maintaining safety and operational integrity, as it might lead to the need for a generator reset or a switch to an alternate power source if necessary. This proactive approach helps in troubleshooting and mitigating any potential issues before they lead to more significant complications during flight.

The other options, while associated with various aircraft systems, do not directly pertain to the IDG's failure modes, which is why they are not the correct interpretation of the FAULT light's indication.