What was found
AIRCRAFT WAS GROUNDED. CABIN PRESSURIZATION NOT MAINTAINED. ONE AIR-CONDITIONING PACK OPERATION AT FL240. CABIN ALTITUDE REACHED 10,000 AFTER 45 MINUTES IN CRUISE. DESCENDED TO 10,000 ALTITUDE WITH OUTFLOW VALVE INDICATING FULL CLOSE AND RIGHT PACK SHOWING 30 PSI. ZERO DIFFERENTIAL PRESSURE UNTIL LANDING. REMOVED AND REPLACED LEAKING RIGHT PACK ISOLATION VALVE PER AMM 36-13-04, RIGHT PACK FLOW CONTROL VALVE PER AMM 21-51-01 (AALA201709139021), AND AIR CYCLE MACHINE DUE TO BROKEN DUCT FLANGE PER AMM 21-51-04 (AALA201709139022). OPERATIONAL CHECK GOOD.