As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) FS 688 BL 0 WL 145 TWO WAY CHECK VALVE USED IN ENGINE EXTINGUISHING SYSTEM, MAY HAVE BEEN ASSEMBLED WITH TWO BALLS 219846 INSTEAD OF ONE BALL AS DWG 446651 REV.E REQUIREMENTS. THE FLOW OF HALON 1301 FIRE EXTINGUISHING AGENT THROUGH THE CHECK VALVE IS PARTIALLY RESTRICTED AS A RESULT OF THE SECOND BALL BEING INSTALLED. TESTING ACCOMPLISHED BY KAD SUGGESTS THAT THE FLOW DURATION THROUGH AN IMPROPERLY ASSEMBLED CHECK VALVE IS EXTENDED BY 30%.