What was found
LEVELING OFF AT FLT 380 CABIN ALTITUDE HORN WENT OFF. CABIN ALT WAS ABOVE 1000FT. COULD NOT RE-ESTABLISH PRESSURE. EXECUTED AN EMERGENCY DESCENT TO 9000FT. ON CREW DEBRIEF, NR 2 ENGINE BLEED WAS INSUFICIENT. TROUBLESHOT TO FAILED S9 ON FIRE CONTROL PNL (P8-1) NOT OPENING PRESSURE OUTFLOW VALVE. PERFORMED HEALTH CHECK IAW 36-11-00. REPLACED HI STAGE REGULATOR FOR OUTFLOW VALVE PX FAULT. REF 26-00- 01 AND 36-11-07. OPS CHECKED BLEED SYSTEM OK. ROTABLE PARTS CHANGE WAS INDICATED - FIRE DECTION MODULE PART NUMBER 69-37307-300, AND HIGH-STAGE REGULATOR PART NUMBER 107484-7.