What was found
ON APPROACH, NLG WOULD NOT EXTEND NORMALLY. AFTER ATTEMPTING FLT MANEUVERS TO EXTEND GEAR, ALTERNATE EXTENSION SYSTEM WAS USED & A/C LANDED SAFELY. MAINT DISCOVERED AN INOPERATIVE NOSE DOOR SEQUENCING VALVE & REPLACED IT. A/C TEST FLOWN & RETURNED TO SERVICE. ON APPROACH, SAME CONDITION EXISTED. ONCE A/C ARRIVED, MAINT R&R NOSE GEAR DOOR ACT, DUE TO ACT BYPASSING ON DOWN SIDE. A/C OPS CHECKED & RETURNED TO SERVICE. LATER THAT DAY, HAD SAME DISCREPENCY. MAINT R&R 3261-K7 RELAY & RETURNED A/C TO SERVICE. NO DISCREPENCIES TO DATE.