As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR TURNBACK, UPON GEAR RETRACTION FELT AND HEARD A LOUD BANG BELOW RUDDER PEDALS, FOLLOWED BY A VIBRATION WHICH INCREASED AS AIRSPEED WENT UP. FOUND NLG DRAG BRACE CRACKED ON UPPER LT SIDE WHERE NLG DOOR ACTUATING ARM CONNECTS. REMOVED AND REPLACED DRAG BRACE ASSY PER MM.