Why might a CSD unit become disconnected in flight?

A CSD (Constant Speed Drive) unit may become disconnected in flight primarily due to a malfunction, such as overheating. When a CSD unit is subjected to excessive temperatures, typically from internal or external factors, it can reach a critical point where it must be disconnected to prevent further damage to the unit and other connected systems. This disconnection is a safety response to potential failure modes that could compromise the aircraft's operational integrity.

CSD units play a crucial role in maintaining consistent electrical frequency for systems powered by the aircraft's generator. When they overheat, the risk not only affects their function but could also impact the overall electrical system, leading to more significant failures if not addressed promptly. Thus, the safety protocols in aviation emphasize immediate action in response to such malfunctions to ensure continued safe operation of the aircraft.