What was found
(CAN) DURING CLIMB THROUGHT FL 20 CABIN ALTITUDE COULD NOT BE MAINTAINED AT REQUESTED ALTITUDE, PRESSURE DIFFERENTIAL. DURING GROUND PRESSURIZATION TESTS IT WAS FOUND THAT THE AIR CONDITIONING EMERGENCY VENT SCOOP DOOR WAS OPENING UNDER PRESSURE, THE SHAFT INNER BONDED BUSHING HAD CAME LOOSE AND HAD WORN A ELONGATED HOLE IN THE COMPOSITE ASSY SIDE WALL ALLOWING THE DOOR TO OPEN UNDER PRESSURE.