What was found
AFTER TAKEOFF, LT MLG DOOR WOULD NOT CLOSE. EXTENDED GEAR, RECEIVED 3 GREEN & THEN RETRACTED GEAR. PROBLEM REMAINED. RAN CHKLIST FOR AMBER CAS LT MLG DOOR & LANDED. PERFORMED MLG SWINGS & VERIFIED WRITE-UP, LT INBD MLG DOOR WOULD CLOSE, BUT NOT LATCH CLOSED CONSITENTLY. INSPD LT DOOR UPLOCK MECH & DID NOT FIND FAULTS. INSPD LT INBD DOOR ACT & FOUND A LOCKING NUT LOOSE. SAFETY WIRE BROKEN. SECURED LOCKING NUT & OPS CHKD, OPS CHKD GOOD. NO ADJUST OR RIGGING REQUIRED. PERFORMED SEVERAL CYCLES OF MLG DOORS & MULTIPLE GEAR SWINGS, DISCREPANCY NO LONGER STANDS. DOWN-JACKED ACFT & RETURNED ACFT TO ORIGINAL CONFIG. WORK PERFORMED IAW AMP BD700-A-J32-30-00-00AAA-340A-A.