As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
INSPECTION TYPE:N/A CREW 02 INDICATOR F/E PANEL SLOWLY DECREASED FROM 1200 TO 0 AFTER 3.5 HOURS OF FLIGHT. SYSTEM PRESS GAUGE SIDE WALL WENT TO 0 PSI. REMOVED AND REPLACED LOWER & UPPER 02 BOTTLES AS PER MM 35-10-00, FOUND UPPER BOTTLES COUPING LEAKING. PART ON ORDER, REMOVED AND REPLACED UPPER CYLINDER 02 REGULATOR, LEAK CHECK C/W NORMAL.