What was found
APPROXIMATELY 30 MIN AFTER DEPARTURE AND PRIOR TO OCEANIC ENTRY, IRS-FMS DISAGREE AND IRS DIVERTED MESSAGES DISPLAYED IN SCRATCHPAD OF FMS. COMPANY ADVISED NOT TO CONTINUE IF MESSAGES DID NOT CLEAR. MESSAGES CLEARED INITIALLY BUT THEN DISPLAYED AGAIN. CORRECTIVE ACTION: REMOVED DEFECTIVE IRU 1 P/N HG2100BB03 S/N 56089586. REPLACED WITH CUSTOMER SUPPLIED REPAIRED IRU P/N HG2100BB03 S/N 56100941. COMPLIED WITH POST MAINTENANCE CHECKS. NO FURTHER DEFECTS TO BE NOTED. FINAL CHECK GOOD. ALL WORK DONE I/A/W CL350 AMM 34-45-01, 34-45-00