As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CAPT O2 MASK DOES NOT TEST PROPERLY ( LEAK TEST FUNCTION). DFR PER MEL 25- 011-06C O2 BOX WILL NOT TEST. PLACARD INSTRALLED CONTACTED MCC OK FOR SVC. SWAPPED CAPT. O2 MASK WITH OBSERVER SEAT O2 MASK, OK TO CONT. ON DEFERRAL. REINSTALLED OBSVRS O2 MASK TO ORIGINAL POS. R/R OBSVRS O2 MASK BOX WITH NEW BOX, R/R CAPT O2 MASK REF A320 AMM 35-12. (LP: 7336902)