What was found
OWNER REPORTED AIRCRAFT WOULD NOT PRESSURIZE TO MAX DIFFERENTIAL. UNABLE TO CLIMB ABOVE 18 K WITHOUT CABIN ALTITUDE WARNING LIGHT ILLUMINATING. CABIN ALTITUDE WOULD CLIMB WHEN REDUCING POWER. THE ENVIRONMENTAL CONTROL SYSTEM WAS VISUALLY INSPECTED WITH NO DEFECTS. PERFORMED GROUND PRESSURIZATION TEST AND NOTED EXCESSIVE LEAKAGE FROM THE ECS SHUTOFF VALVE LINKAGE AND EMERGENCY SCOOP WAS CLOSING COMPLETELY. THE SCOOP ASSEMBLY HAS WORN EXCESSIVELY AT THE SCOOP SHAFT (HOLES WORN OUT). SCOOP IS MADE OUT OF COMPOSITE MATERIAL. SUGGEST MAKING UNIT FROM STRONGER MATERIAL OR INSTALLING BUSHING ON SHAFT AT MANUFACTURE. REPLACED SCOOP ASSEMBLY WITH NEW UNIT AND PERFORMED GROUND PRESSURIZATION TEST. ALL OPERATIONS SATISFACTORY AT THIS TIME.