As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
90 DEGREE ELBOW TUBE ASSEMBLY LEADING WHERE FITTING GOES ON TO THE REGULATOR VALVE AS O-RING. DATA THE SDR DESCRIBES AN AIR LEAK AT THE INTERFACE BETWEEN THE SLIDE BOTTLE REGULATOR ASSEMBLY AND THE 90 DEGREE ELBOW TUBE LEADING TO THE PRESSURE GUAGE. REPLACED O-RING TO STOP LEAK.