What was found
AIRCRAFT TURNED BACK, STRONG VIBRATION IN FUSELAGE. ARRIVING IT WAS DETECTED THAT THE LT NLG DOOR WAS OPENED. THE FUSELAGE WAS VISUALLY INSPECTED, ALL CORRECT. AIRCRAFT TAKEN TO HANGAR, BOTH NLG DOOR ACTUATORS WERE REPLACED AND SYSTEM TESTED IAW MM 32-22-01, ALL CORRECT.