How to automatically turn off external hard-drive connected to Time Capsule when idle? I have a 5th generation AirPort Time Capsule (3TB) with an additional G-DRIVE GEN4 (3TB) external hard-drive attached to it. The external hard-drive has an on/off switch.

Is it possible- and how can I make it so that the external hard-drive turns off or hibernates after a period of being idle, without turning off the power switch? I don't want it to be always active.

The external hard-drive is not used as a Time Machine backup drive; I'm only using it as a network share/network-attached storage, so that we can share files more easily within the household.
Not possible. The Time Capsule does not supported that feature.