What was found
(CAN) WHILE CARRYING OUT THE OXYGEN MASK INSPECTION IAW REF 1 AND REF 2 ON SUBJECT ACFT AT THE C9 CHECK, SEVERAL MASKS NOT COVERED BY THE INSPECTION PARAMETERS WERE FOUND WITH BROKEN OR CRACKED FLOW INDICATOR VALVES WERE ON MASKS (PN 174080-96, MFR DATES 1-92,12-92,03-93,06-91), BUT THE INSPECTION CARD ONLY SAYS TO LOOK AT OTHER MASKS. THE 5TH DAMAGED INDICATOR VALVE WAS ON A MASK (174095-96) WITH A MFG DATE OF 03-27-2001. THE INSP CARD SAYS ONLY TO LOOK FOR MASKS WITH DATES BETWEEN 01-01-2002 AND 01-03-2006. THE CAUSE IS THAT THE OPERATOR`S SHOP MAY HAVE ASSEMBLED DIFFERENT O2 MASK PARTS INTO ONE.