What was found
LOCK NUT THREADS FAILED, MLG STRUT EXTENDED ON TAKEOFF ALLOWING MLG TO SWING FREE. DURING LANDING, MLG WAS UNDER FUSELAGE CAUSING DAMAGE TO LOWER LONGERONS, CONDITION OF THREADS CANNOT BE DETERMINED WITHOUT DISASSEMBLING THE MLG STRUT ASSY. THEREFORE, THE THREADS MAY DETERIORATE SIGNIFICANTLY WITHOUT DETECTION. SUGGEST SPECIAL EMPHASIS INSPECTION ROUTINE AT (5) YEAR INTERVALS TO INCLUDE DISASSEMBLY OF MLG STRUT ASSY. (K)