What was found
DURING GROUND LEAK CHECK AND PRESSURE CHECK OF DEICE BOOT SYS, FOUND LT AND RT CHECK VALVES INOPERATIVE. REMOVE AND INSPECTED CHECK VALVES. FOUND VALVES WORN AND MISSING INTERNAL PARTS. NORMAL OPERATIONAL CHECK OF THE DEICE BOOT SYS DOES NOT INDICATE AND MALFUNCTION. GROUND PRESSURE CHECK OR REMOVAL AND VISUAL INSPECTION OF VALVES WOULD BE REQUIRED TO IDENTIFY ANY MALFUNCTION. RECOMMEND FILTERS INSTALLED AFT THE CHECK VALVE TO PREVENT DEBRIS FROM AIR PUMP OR CHECK VALVE FROM ENTERING PRESSURE LINES.