What was found
STL - DURING DESCENT, NR 2 ENGINE, S/N 3231, WAS SHUT DOWN DUE TO FIRE INDICATION LIGHT ILLUMINATION AND FIRE BELL SOUNDED. BOTH FIRE EXTINGUISHER BOTTLES WERE DISCHARGED. REMOVED AND REPLACED NR 2 ENGINE FIRE DETECTION CONTROL UNIT, MFG P/N 892809-0400-02. OPERATIONAL CHECK NORMAL.