As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NOSE LANDING GEAR WOULD NOT DEPLOY ON APPROACH TO LANDING. AFTER NLG REMOVAL, IT WAS DISCOVERED THAT THE NLG ACTUATOR DRIVE SHAFT PN 50820218 INTERNAL SPLINE WAS WORN AND SHEARED. LUBE POINTS ON DRIVE SHAFT TO LUBE SPLINES TO REDUCE WEAR. (K)