07 Mar 2017 14:10
If one engine generator fails, the system will automatically replace the failed generator with the APU generator, if it is available, or the other engine generator. Part of the galley load will be shed automatically and, if fitted, the DC entertainment bus will also be shed.
So if an engine generator is lost the entire system can be supplied by the remaining engine generator or the APU so the entire system remains powered.
Failure of AC Bus
If AC BUS 1 fails AC BUS 2 can supply the AC ESS BUS and the ESS TR can supply the DC ESS BUS. Depending on the MSN of the aircraft this either occurs automatically or can be recovered by switching the AC ESS FEED to ALTN on the overhead panel. If manual switching is required both the AC and DC ESS BUS FAULTS will show on the ECAM. DC BUS 2 supplies DC BUS 1 and DC BAT BUS automatically after 5 seconds.
TR1 or TR2 can supply both DC BUS1 and DC BUS2 via the DC BAT BUS. so if TR 2 fails to slack is taken up by TR1 and DC BUS 2 is supplied via the DC BAT BUS and vice versa.
A TR 1 or 2 FAULT ECAM caution is for crew awareness. The status page states the aircraft is now cat 3 single and the inop systems are the associated TR and cat 3 dual.
If TR1 fails the DC ESS BUS looses its power source so in this case the ESS TR via the AC ESS bus, will power the DC ESS bus.
Failure of a DC BUS
DC BUS 1 Fault
The system display will show DC 1 in amber and, as with a TR 1 fault the DC ESS BUS is now powered via the ESS TR.
DC BUS 2 FAULT
AIR DATA SWTG - F/O 3. as the First officers side has lost air data this is self explanatory.
BARO REF CHECK - SINCE FCU CHANNEL 2 is lost the barometer settings need to be crosschecked on the FCU and PFD.
CAB PRESS - SYS 2 in amber
FUEL - L+R tank and Centre tank pump 2 inop
WHEEL - gear indications missing due to LGCIU 1 + 2 in op
F/CTL - SPOILERS 1 2 AND 5 INOP ELAC 2 AND SEC 2 AND 3 IN OP
Read ECAM source: