What was found
DURING AN INVESTIGATION CONCERNING A NLG COLLAPSE, DISCOVERED THE LOWER STRUT SUPPORT BRACKET ONLY HAD 1 OF 2 BOLTS SECURING IT. AFTER THE ACFT LANDED, THE BRACKET BROKE AWAY FROM THE NOSE GEAR. AS THE ACFT TURNED ONTO THE TAXIWAY, LATERAL LOADS CAUSED THE UPPER SUPPORT MOUNT TO TEAR AWAY FROM THE FIREWALL, THUS CAUSING A PROPELLER GROUND STRIKE. WHEN THE REMAINDER OF THE BRACKET WAS REMOVED FOR ANALYSIS, IT WAS NOTICED THE REMAINING BOLT SELF-LOCK LOCK NUT DID NOT HAVE ANY MECHANICAL RESISTANCE. IT IS SURMISED THAT VIBRATION OVER TIME MAY HAVE CAUSED THE OTHER SELF-LOCKING NUT TO BACK OFF AND ULTIMATELY ALLOW THE BOLT TO FALL OUT.