In Flight - Bus Transfer switch OFF

IDG 1 has failed.

  • The BTBs open and power to Transfer Bus 1 and its associated
    busses is lost.

  • The left TRANSFER BUS OFF and SOURCE OFF lights are
    illuminated.

  • TR 1 and is not powered and power to DC Bus 1 is lost.
  • The AC Standby Bus is powered from the Inverter and Battery Charger

  • The DC Standby Bus is powered by the battery and the battery is being
    charged.

  • The Cross Bus Tie Relay opens and the automatic function is lost.
Electrical System SGR
Moving the Bus Transfer switch to OFF in flight is used only during some
electrical abnormal procedures.