What was found
LOST LT ENGINE GENERATOR AFTER DEPARTURE FROM FRA. FLIGHT CONTINUED WITH APU RUNNING UNTIL APU SHUTDOWN. DIVERTED TO LHR WHERE OVERWEIGHT LANDING WAS MADE. THE APU GEN WAS SELECTED IN PLACE OF LEFT GEN. HOWEVER, THE APU HAD AN AUTO SHUTDOWN RESULTED IN A DIVERTION TO LHR. THE REMOVED IDG FINDING REPORT IS NOT AVAILABLE AT THIS TIME. HOWEVER, IT WAS SUSPECTED THAT THE IDG EXCITER FAILURE COULD RENDER THE IDG INOPERATIVE. THE LEFT IDG WAS REPLACED.