What was found
AT FL 340 HEARD LOW RUMBLING & LOW VIBRATION ON OUR FEET, NOISE & VIBRATION CEASED AT FL 160 ON DESCENT. ALL INDICATIONS NORMAL GOOD CABIN PRESSURE. AS A RESULT OF INSP FOUND RT RAD MISSING AND HINGE BROKEN. PERFORMED AIRFRAME VIBRATION CONDITIONAL INSPECTION PER AMM 05-51-38-2 IN PROGRESS. DETAILED INSP OF RT PACK RAD INLET, EXHAUST & NOZZLE-WATER SPRAY SYS FOUND NO DEFECTS NOTED. ALSO NO ANY OBSTACLES/DAMAGED RAD DOOR PER AMM 21-53-01-4, 21-53-02-4 & 21-53-05-6. INSTALLED THE RT RAD ASSY & PERFORMED POST-INSTALLATION TEST FAIL PER MM 21-53-01-4. R&R EXHAUST DOOR ACTUATOR & POST-INSTALLATION TEST NORMAL IAW AMM 21-53-04-4. ACFT OK FOR SVC.