What was found
1. AIRCRAFT B-16103 DURING CRUISE 5 MINUTES BEFORE TOD, "ENG 2 RPM LO" LEVEL 2 ALERT APPEARED. FOLLOWED CHECK LIST, AIR RESTART WAS SUCCESSFUL.2. ON GROUND, CHECK CFDS NO RELATED FUALT FOUND.3. CHECK ENGINE CONDITION ALL NORMAL. EEC TEST PASS. PERFORM ENGINE RUN CHECK NORMAL PER MM 71-00-00.4. NEXT SEVERAL FLIGHTS, ENGINE 2 OPERTION WERE NORMAL.5. ON AUG/05, FOR MAINTENANCE PREVENTION, REPLACED THE HMU AND OPERATION CHECK NORMAL.