AN AIRBUS 300 IN CRUISE AT FL350 HAD THE #1 AC BUS FAIL AND COULD NOT PWR THE BUS WITH THE APU GENERATOR BUS.

Narrative

ACFT WAS ON A MAINT FERRY FROM PHL TO TUL. APPROX 2 HRS 10 MINS INTO THE FLT; THE #1 GENERATOR FAULTED. AT THIS TIME; ACFT WAS AT FL350 AND FUEL WAS XFERRING FORWARD FROM THE TRIM TANK TO THE CTR. THE APU WAS RUNNING; HAVING BEEN STARTED AS A PRECAUTION AT PHL AND REMAINED RUNNING THROUGHOUT THE FLT. WHEN GENERATOR #1 FAULTED; THE APU PICKED UP THE LOAD ON AC BUS #1. THE ECAM ELECTRICAL PAGE SHOWED GENERATOR #1 WITH NO VOLTS/FREQ AND ALL ELECTRICAL BUSSES PWRED. APPROX 10 MINS AFTER GENERATOR #1 FAILED; THE APU DROPPED OFF THE LINE FAILING THE AC BUS #1 AND THE AC ESS BUS. GENERATOR #2 THEN FAILED TO PICK UP AC BUS #1. AT THIS TIME; ACFT HAD A GENERATOR #1 FAULT AND AN AC ESS BUS FAULT. 'OVRD SUPP #2' WAS SELECTED ON AND IT PWRED THE AC ESS BUS. THE AC BUS #1 REMAINED UNPWRED. AFTER LNDG; THE GPCU PANEL IN THE E&E COMPARTMENT SHOWED A GCU FAIL; CODE BC AND A DP TRIP. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE ACFT WAS AN AIRBUS 300 AND WAS ON A MAINT FERRY. THE RPTR SAID THE FOLLOWING UNITS WERE REPLACED TO CORRECT THE #1 BUS FAILURE PROBS: ESSENTIAL XFORMER RECTIFIER UNIT; L CTR TANK FUEL BOOST PUMP; THE #1 GENERATOR CTL PANEL AND THE #1 INTEGRATED DRIVE UNIT WAS SVCED. THE RPTR STATED THE AIRPLANE THEN WAS RTED TO KIN WHERE THE #1 BUS AGAIN FAILED AND THE ACFT WAS MAINT FERRIED TO ZZZ FOR CORRECTION. THE RPTR SAID MAINT FOUND CHAFFED WIRING WHICH WAS SENSED AS A DIFFERENTIAL FAULT CAUSING THE #1 BUS TO TRIP AND LOCKOUT THE APU BUS FROM PWRING THE #1 BUS.