As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FIRST OFFICER'S 02 MASK IS LEAKING AT HARNESS THAT INFLATES WHEN DONNING 02 MASK. FOUND DURING PREFLIGHT. SWAPPED FIRST OFFICER`S MASK WITH OBSERVER'S MASK IAW AMM 35-11-12, DEFERRING OBSERVER'S MASK IAW MEL 35-10-01. R & R OBSERVER'S 02 MASK IAW AMM 35-11-12. OPS CHECKED GOOD, OK FOR SERVICE. THIS CLEARS DI 3233124-1.