The hot battery bus cannot be de-energized. Its always live unless it is physically disconnected at the teminals.
With all generators inop and standby power off systems powered bat switch on:
standby comp lt
white dome lt
instr flood lt
crew o2
pax o2
standby airstair
upper DU
thrust revesers
starter valves
right ignitors
APU ops
Capt pitot heat
xfeed valve
engine fuel shut off valve
spar sov
fuel qty
AC pack valves
Manual press control
cabin alt warning
Capt EFIS control panel
Capt outboard DU
Capt ND
ILS#1
Left ILS, GPS
Marker beacon
ADF#1
DME#1
Mag compass
Standby instruments clocks
flight interphone
PA
VHF #1
service interphone
engine hyd sov
stby rudder sov
inbd antiskid sys
parking brake
air/gnd sensor sys
landing gear indicators
APU fire detection
APU fire bottle
ENG fire detection
ENG fire bottles
Cargo fire bottles
Stall warning sys
Aural warnings
Master caution sys
Switching the battery off you would lose all of the above which are the essentials to keep the ac flying. The exceptions being the fire detection and protection sys as they are connected to the hot battery bus.
As mentioned before seperating the systems is used for load shedding and to isolate a smoke/fire source. There isn't anything in the QRH which requires you to switch off the switched bat bus(bat switch) as you would lose all listed above. If the prob came down to one of the above systems causing a major problem you could pull some CB to isolate it.
kempus
Last edited by Kempus; 25th September 2008 at 12:21.
Reason: spelling