As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON PREFLIGHT CREW QXYGEN WAS 10 AT TOP OF CLIMB QUANTITY WAS 6.5 MONITORED FOR THE NEXT 25 MINUTES AND QUANTITY DROPPED TO 5.5 NOTIFIED DISPATCH AND RETURNED TO SDF. REMOVED AND REPLACED BOTH CREW O2 BOTTLES PER MM 12-15-08 REMOVED AND REPLACED 2ND OBS O2 REG. AND MASK PER MM 35-11-07 AND OPS CHECKED PER 35-11-07(MASK ASSY P/N 358-1510V S/N N/S/N LOC FIRST OBS