What was found
FLIGHT 3420 - LAS/LAX - PILOT REPORTED THAT DURING TAKEOFF, AT APPROXIMATELY 400 FEET A LOUD BANG WAS HEARD COMING FROM THE LT ENGINE, AT WHICH TIME THE ENGINE STARTED TO SHUTDOWN CONSISTENT WITH A COMPRESSOR STALL. INFLIGHT SHUTDOWN PROCEDURES WERE EFFECTED ON THE LT ENGINE AND THE AIRCRAFT RETURNED TO THE FIELD WITHOUT INCIDENT. MAINTENANCE PERSONNEL PERFORMED AN INLET COMPRESSOR INSPECTION AS WELL AS A BORESCOPE ON THE COMPRESSOR AND HOT SECTION, WITH NO DEFECTS NOTED. THE AIRCRAFT WAS RELEASED FOR A FUNCTIONAL CHECK FLIGHT WHICH IT SUBSEQUENTLY FAILED FOR THE IDENTICAL PROBLEM.