As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FIRST OBSERVERS OXYGEN MASK NOT TESTING(<P>SUSPECT FO'S OXYGEN STORAGE BOX AND MASK WITH FIRST OBSERVERS SEAT PER AMM 35-11-51. DEFERRING FIRST OBSERVERS SEAT TO DMI 210052 PER MEL 25-11-02-01 CAT A DUE DATE 06JUN24. PLACARDS INSTALLED. LEAK CHECKS OK. REMOVED AND REPLACED FIRST OBSERVERS STORAGE BOX & LEAK CHECKS OK IAW AMM 35-11-51. DMI 210052 CLOSED.</P>)