What was found
AFTER O2 MASK WERE USED IN FLIGHT ALL 3 O2 BOTTLES DROPPED TO 0 PSI. SERVICED ALL 3, CREW O2 BOTTLES PER AMM 12-14-35. CHECKED ALL BOTTLES AND MASK SYSTEMS FOR LEAKS PER AMM 35-11-00-06-0. FOUND ONE RT COURIER MASK SLIGHTLY LEAKING AT INTIAL BOTTLE RESERVICE. LEAK STOPPED AFTER 500 PSI WAS ADDED TO O2 BOTTLES. PER CREW SUSPECT FIRST OFFICERS MASK WAS STUCK IN ON POSITION AFTER IT'S USE. OPERATED ALL MASKS AFTER SERVICE. ALL MASKS OPERATE NORMALLY PER AMM 35-11-00-06-0.