PRACTICE LAB / ELECTRICAL
IDG bus transfer
Keep ELEC open while the aircraft is powered from the GPU or APU. Record the source shown for each AC bus. [56]

Start one engine
Use the normal FSS start procedure. When the IDG comes online, check the source shown for that engine’s AC bus.
Check the transfer
FSS says the onside IDG normally replaces the previous source on its bus. Compare both bus indications before and after the start. If they differ from the documented sequence, check engine state, IDG selection and source availability. [56]