Left APU GEN switch selected ON.

  • The APU breaker closes.

  • Both BTBs remain closed powering Transfer Bus 1 and
    Transfer Bus 2.

  • The APU GEN OFF BUS light extinguishes.

  • The right SOURCE OFF light illuminates indicating that the right
    APU GEN switch has not yet been selected ON.

  • The External Power breaker opens and the previously selected
    source (Ground Power) is no longer connected.

  • The GROUND POWER AVAILABLE light illuminates.
The sequence of bus switching in the Electrical System SGR is for illustrative
purposes only  and is not meant to imply an approved procedure.
Electrical System SGR
Select