What was found
AIR INTERRUPT, EMER DECLARED, LANDING UNEVENTFUL & ACFT NOT OVERWEIGHT. DURING CLIMB VIBRATION WAS FELT IN THE NLG AREA. CONTINUED AROUND THE TRAFFIC PATTERN UNTIL THE NLG WAS LOWERED. POST FLIGHT WALK AROUND REVEALED THAT THE LT GEAR DOOR WAS CLOSED & THE RT GEAR DOOR WAS OPEN. GND CREW REPORTED THAT THE NLG DOOR REMAINED OPEN DURING DEPARTURE. ACCOMPLISHED NOSE GEAR RETRACTION IAW 32-30-00. NOSE GEAR DOORS OPERATED NORMAL. FOUND RT AFT FIXED GEAR DOOR LOOSE. R & R HINGE IAW 32-22-01. BOLTS CHECKED NORMAL.