What was found
ETOPS SIGNIFICANT SYSTEM -CABIN PRESSURIZATION UNABLE TO MAINTAIN SCHEDULE ALTITUDE AT FL 380 W/ENG ANTI ICE ON. DUCT PRESS 15 PSI, OUTFLOW VALVE FULLY CLOSED, CABIN CLIMB AT 300 FPM REACHED 8500' (SCHED IS 6500') COND SAME IN AUTO1 OR AUTO2 W/ENG ANTI-ICE OFF CABIN ALT DESCEND BACK TO 6500'. PERFORMED FIM21-31-00 FIG 103. NO DEFECTS NOTED. PERFORMED AMM 36-23-00 AIR SUPPLY BITE SYS TEST NO DEFECTS NOTED TOOK AC ON HIGH POWER RUN. NO DEFECTS NOTED ON L/R ENG BLEED AIR SYS ACCOMP FIM36-10-00/101 FIG 28A. REMOVED AND REPLACED BOTH LT/RT PRV CONTROLLER PER AMM36-11-19. OPS AND SEC CHECK OF PRV CONTROLLERS GOOD PER AMM36-11-19.