A320
Flight Crew Last 90 Days 211
Aircraft Equipment Problem Critical
Flight Crew Overcame Equipment Problem; Flight Crew Returned To Gate; General Maintenance Action
Aircraft
About three minutes into the taxi out phase; the lighting; instruments; door lock; First Officer's CRT's generator transfer and number 2 bus all started to 'go nuts.' The lights were blinking on and off; the taxi light was going on and off. The door was locking and unlocking. My CRT's were flashing on and off and ECAM's were blinking on and immediately going off. The generator was clicking on and off; transferring back and forth to the APU [#1] generator. Lighting in the cabin was flashing with each transfer and they were transferring every couple of seconds. My (com 2) radio was unreadable and at times had a constant tone like a carrier only with no voice capability on the frequency. It all seemed to be associated with the #2 generator and its transferring issues. It would connect; and then trip off while the transfer appeared to disrupt momentarily all the items associated with the number two generator.The Captain taxied to the de-ice area and set the brakes to work the issue and call Maintenance Control. I got out the QRH but no ECAM stayed on the screen long enough to try to run either an ECAM or a checklist. We decided to disconnect [deselect] the generator and run on one generator and then started the APU to run on that. By then my instrument CRT's and the bottom screen all had slashes across them and did not come back until we were almost at the gate after taxi back. NOTE: the Maintenance person advised after a reset like ours it takes quite a while to run the self-tests and get back on line.We were able to stabilize the situation with the #2 generator off and the APU on (although I believe just turning off the #2 generator would have eventually cleared it up). I feared that we had permanently damaged some electrical items with the rapid and incomplete power transfers.
We started both engines and with taxi clearance began to taxi. The First Officer; as part of his flows; turned the APU off. Approximately 1-2 minutes later; we started getting multiple ECAM messages to include SEC 2; ELAC 2 faults along with what sounded like generator relay switching. (The ECAM messages would constantly cycle through the faults). The taxi light; cabin and cockpit lights would intermittently go on and off. Both the First Officer's ND and PFD along with the lower ECAM displays turned to diagonal lines. We stopped the aircraft and eventually turned the #2 GEN off. This stabilized the flashing lights and ECAM. We started the APU and put the APU GEN on line. This was verified by selecting the ELEC page on the ECAM. The First Officer's ND and PFD along with the lower ECAM still displayed a diagonal line. Once stopped the lead Flight Attendant called to ask what was going on due to the flashing cabin lights. I made a PA announcement informing the passengers that we had an electrical problem and have stabilized the problem. We contacted Maintenance Control via phone and coordinated a return to the gate (this took about 20 minutes). The taxi back to the gate was uneventful. We parked the aircraft and shut down both engines. External power was applied and the APU was shut down. After the APU was shut down and on external power; the First Officer's ND and PFD along with the lower ECAM returned to their normal display.
A320 flight crew describes an electrical anomaly during taxi out for takeoff; apparently caused by the number two generator connecting and disconnecting from AC Bus 2 rapidly. Eventually the number two generator is turned off and the APU started stabilizing the electrical system before returning to the gate.