Narrative:

Enroute at FL370; we got multiple ECAM cautions that included AC bus 2 fault and gen 2 fault. Along with the ECAM cautions; we experienced the loss of the autothrust system; the sd; and the first officer's pfd; nd; and FMGC. As I had my 'screens' available; I continued to fly and the first officer handled the ECAM and flight manual reference work. The purser called and advised that they had lost power to the galleys shortly after. The first officer handled a few action items on the ECAM (selecting N1 mode; selecting override on the extract fan and an attempt to reset the #2 generator). The generator would not reset so nothing from the ECAM action list restored any of our lost equipment. Shortly into the event; I made the decision to divert to ZZZ. The autoplt was working fine but I had to assume the role of the autothrust system. As we descended; ATC provided vectors and altitudes into ZZZ. After the first officer completed researching the FM irregular procedures; and had a chance to talk; we decided to call maintenance and we agreed that the divert was the right course of action. At some point we were able to let the flight attendants know what was going on although the information we provided was quite brief. During the event; we both scratched our heads as to what exactly was happening; as without the sd; we couldn't get a 'system' picture of our electrical state. We knew that gen 1 had not picked up anything and the 'overall picture' we were seeing was eerily similar to the emergency electrical configuration (4 screens). We spent a portion of our time on the event trying to figure a way to access the system display information to no avail. This led to some frustration and added to our task saturation. As we approached the downwind leg to xxl; the first officer; who had already started the APU (which; by the way; would not automatically power the AC2 bus) asked to try another reset on GEN2. This action resulted in restoring what appeared to be all of our lost equipment. A check of the now available sd confirmed that the APU generator had picked up the AC2 bus. About 5 to 10 minutes before touchdown; either maintenance or dispatch sent us an ACARS message for contact. We did not respond until we were safely on the ground. The landing was normal; all the flight controls worked throughout the flight; and the brakes and nosewheel steering worked normally. At the gate; we briefed maintenance as they download the event from the FMGC's. In addition to confirming all of our equipment losses; maintenance also noted we had lost TR2 as well. They completed some analysis and performed a few tests with the #2 engine running. Ultimately; they advised that we had experienced a #2 idg failure. Apparently the #2 idg had some prior write-ups which helped them confirm it as the culprit. I asked why an idg failure would take out the AC2 bus and why we didn't get the #1 gen to automatically pick up the AC2 bus. No one could offer an explanation. We were told that it would be a three hour fix; and felt that if an idg failure on this particular aircraft could cause a bus loss; that we did not think it wise to have it deferred and continue to destination. A replacement aircraft was scheduled for us to complete the flight. We wrote up into the maintenance log AC bus 2 fault; GEN2 fault; and TR2 fault.callback conversation with reporter acn 777307 revealed the following information: the reporter stated that this aircraft had a history of electrical system faults related to the idg but they were intermittent and had not led maintenance to pinpoint the idg as the root cause. He followed the aircraft's flight history for several days after this event and found no additional electrical faults occurred. He therefore assumed that the idg change solved the reoccurring idg faults.callback conversation with reporter acn 776813 revealed the following information: the reporter stated that maintenance disconnected the idg then reconnected it and started the #2 engine at the gate. The idg gen indications were normal but it would not power AC bus 2. Maintenance was unsure if the idg or generator control unit (gcu) was the problem and were unable to explain the in flight failure indications.

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Original NASA ASRS Text

Title: AN A320 #2 IDG FAILED IN FLT. GEN 1 DID NOT POWER AC BUS 2 AND TR 2 FAILED. AFTER RESETTING GEN 2 WITH THE APU ON LINE; AC BUS 2 SWITCHED TO THE APU.

Narrative: ENROUTE AT FL370; WE GOT MULTIPLE ECAM CAUTIONS THAT INCLUDED AC BUS 2 FAULT AND GEN 2 FAULT. ALONG WITH THE ECAM CAUTIONS; WE EXPERIENCED THE LOSS OF THE AUTOTHRUST SYSTEM; THE SD; AND THE FO'S PFD; ND; AND FMGC. AS I HAD MY 'SCREENS' AVAILABLE; I CONTINUED TO FLY AND THE FO HANDLED THE ECAM AND FLT MANUAL REFERENCE WORK. THE PURSER CALLED AND ADVISED THAT THEY HAD LOST POWER TO THE GALLEYS SHORTLY AFTER. THE FO HANDLED A FEW ACTION ITEMS ON THE ECAM (SELECTING N1 MODE; SELECTING OVERRIDE ON THE EXTRACT FAN AND AN ATTEMPT TO RESET THE #2 GENERATOR). THE GENERATOR WOULD NOT RESET SO NOTHING FROM THE ECAM ACTION LIST RESTORED ANY OF OUR LOST EQUIPMENT. SHORTLY INTO THE EVENT; I MADE THE DECISION TO DIVERT TO ZZZ. THE AUTOPLT WAS WORKING FINE BUT I HAD TO ASSUME THE ROLE OF THE AUTOTHRUST SYSTEM. AS WE DSNDED; ATC PROVIDED VECTORS AND ALTITUDES INTO ZZZ. AFTER THE FO COMPLETED RESEARCHING THE FM IRREGULAR PROCS; AND HAD A CHANCE TO TALK; WE DECIDED TO CALL MAINT AND WE AGREED THAT THE DIVERT WAS THE RIGHT COURSE OF ACTION. AT SOME POINT WE WERE ABLE TO LET THE FLT ATTENDANTS KNOW WHAT WAS GOING ON ALTHOUGH THE INFORMATION WE PROVIDED WAS QUITE BRIEF. DURING THE EVENT; WE BOTH SCRATCHED OUR HEADS AS TO WHAT EXACTLY WAS HAPPENING; AS WITHOUT THE SD; WE COULDN'T GET A 'SYSTEM' PICTURE OF OUR ELECTRICAL STATE. WE KNEW THAT GEN 1 HAD NOT PICKED UP ANYTHING AND THE 'OVERALL PICTURE' WE WERE SEEING WAS EERILY SIMILAR TO THE EMER ELECTRICAL CONFIGURATION (4 SCREENS). WE SPENT A PORTION OF OUR TIME ON THE EVENT TRYING TO FIGURE A WAY TO ACCESS THE SYSTEM DISPLAY INFORMATION TO NO AVAIL. THIS LED TO SOME FRUSTRATION AND ADDED TO OUR TASK SATURATION. AS WE APCHED THE DOWNWIND LEG TO XXL; THE FO; WHO HAD ALREADY STARTED THE APU (WHICH; BY THE WAY; WOULD NOT AUTOMATICALLY POWER THE AC2 BUS) ASKED TO TRY ANOTHER RESET ON GEN2. THIS ACTION RESULTED IN RESTORING WHAT APPEARED TO BE ALL OF OUR LOST EQUIPMENT. A CHECK OF THE NOW AVAILABLE SD CONFIRMED THAT THE APU GENERATOR HAD PICKED UP THE AC2 BUS. ABOUT 5 TO 10 MINUTES BEFORE TOUCHDOWN; EITHER MAINT OR DISPATCH SENT US AN ACARS MESSAGE FOR CONTACT. WE DID NOT RESPOND UNTIL WE WERE SAFELY ON THE GND. THE LNDG WAS NORMAL; ALL THE FLT CTLS WORKED THROUGHOUT THE FLT; AND THE BRAKES AND NOSEWHEEL STEERING WORKED NORMALLY. AT THE GATE; WE BRIEFED MAINT AS THEY DOWNLOAD THE EVENT FROM THE FMGC'S. IN ADDITION TO CONFIRMING ALL OF OUR EQUIPMENT LOSSES; MAINT ALSO NOTED WE HAD LOST TR2 AS WELL. THEY COMPLETED SOME ANALYSIS AND PERFORMED A FEW TESTS WITH THE #2 ENGINE RUNNING. ULTIMATELY; THEY ADVISED THAT WE HAD EXPERIENCED A #2 IDG FAILURE. APPARENTLY THE #2 IDG HAD SOME PRIOR WRITE-UPS WHICH HELPED THEM CONFIRM IT AS THE CULPRIT. I ASKED WHY AN IDG FAILURE WOULD TAKE OUT THE AC2 BUS AND WHY WE DIDN'T GET THE #1 GEN TO AUTOMATICALLY PICK UP THE AC2 BUS. NO ONE COULD OFFER AN EXPLANATION. WE WERE TOLD THAT IT WOULD BE A THREE HOUR FIX; AND FELT THAT IF AN IDG FAILURE ON THIS PARTICULAR ACFT COULD CAUSE A BUS LOSS; THAT WE DID NOT THINK IT WISE TO HAVE IT DEFERRED AND CONTINUE TO DEST. A REPLACEMENT ACFT WAS SCHEDULED FOR US TO COMPLETE THE FLT. WE WROTE UP INTO THE MAINT LOG AC BUS 2 FAULT; GEN2 FAULT; AND TR2 FAULT.CALLBACK CONVERSATION WITH RPTR ACN 777307 REVEALED THE FOLLOWING INFO: THE RPTR STATED THAT THIS ACFT HAD A HISTORY OF ELECTRICAL SYSTEM FAULTS RELATED TO THE IDG BUT THEY WERE INTERMITTENT AND HAD NOT LED MAINT TO PINPOINT THE IDG AS THE ROOT CAUSE. HE FOLLOWED THE ACFT'S FLT HISTORY FOR SEVERAL DAYS AFTER THIS EVENT AND FOUND NO ADDITIONAL ELECTRICAL FAULTS OCCURRED. HE THEREFORE ASSUMED THAT THE IDG CHANGE SOLVED THE REOCCURRING IDG FAULTS.CALLBACK CONVERSATION WITH RPTR ACN 776813 REVEALED THE FOLLOWING INFO: THE RPTR STATED THAT MAINT DISCONNECTED THE IDG THEN RECONNECTED IT AND STARTED THE #2 ENG AT THE GATE. THE IDG GEN INDICATIONS WERE NORMAL BUT IT WOULD NOT POWER AC BUS 2. MAINT WAS UNSURE IF THE IDG OR GENERATOR CTL UNIT (GCU) WAS THE PROBLEM AND WERE UNABLE TO EXPLAIN THE IN FLT FAILURE INDICATIONS.

Data retrieved from NASA's ASRS site as of May 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.