As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 4014 - LEFT MLG WOULD NOT LOCK IN THE 'UP' POSITION WHEN GEAR WAS RETRACTED AFTER TAKEOFF. AIRCRAFT RETURNED TO THE FIELD, LANDED WITHOUT FURTHER INCIDENT. PIT MX CLEANED AND LUBRICATED THE MLG 'UP' LOCK ROLLERS IAW MM 32-00-00 AND STD MX PRACTICES. AIRCRAFT RETURNED TO SERVICE. (X)