What was found
WITH LT IDG ON MEL, APU WAS OPERATING ON THE GROUND. APU PERFORMED AN AUTO SHUTDOWN. APU WAS RESTARTED AND SHUTDOWN AGAIN. AFTER SEVERAL ATTEMPTS AT REPLACING COMPONENTS (SURGE VALVE, ECU, LCIT SENSOR), APU REPLACED (11FEB04). VERIFICATION FLIGHT WAS PERFORMED SUCCESSFULLY ON 12FEB04.