What was found
WHEN LANDING GEAR WAS RETRACTED, SEVERAL KNOCKS WERE HEARD COMING FROM THE NOSE GEAR AREA. NOISES WERE FOLLOWED BY A VIBRATION AND FLUTTER. CREW CYCLED LANDING GEAR AFTER PERFORMING A SUCCESSFULL UPLOCK CHECK. PROBLEM REMAINED. MAINTENANCE INSPECTED AND FOUND THE RIGHT NOSE GEAR DOOR TO BE OPEN. PERFORMED GEAR SWING. CYCLED GEAR SEVERAL TIMES. OPS CHECKED GOOD IAW DC-8 MM 32-22-01. MAINTENANCE INSPECTED AREA FOR STRUCTURAL DAMAGE. NONE WAS NOTED.