What was found
(CAN) PART NUMBER K38667 DROP-OUT OXYGEN MASK ASSY [65 PSI SYSTEM] FOUND TO BE INSTALLED ON POST MOD 50043A - BAROMETRIC VALVE AUTOMATIC DROP-OUT [5-9 PSI SYSTEM] AIRCRAFT. BAE PC SHOWS P/N K38667 MASK ASSY WITH AIRCRAFT EFFECTIVITY SERIAL NUMBERS 001-999. MOD 50043A LOWERS PASSENGER OXYGEN SYSTEM PRESSURE FROM 65 PSI TO 5-9 PSI AND REQUIRES P/N K38669 MASK ASSY. BAE IPC SHOWS P/N K38669 MASK WITH NO EFFECTIVITY CODE. SUBMITTER STATES THAT THIS PROBLEM WAS FOUND ON ALL FIVE OF THEIR OPERATOR'S FLEET.