What was found
IAH - FLT 1926 - THE NR 3 ENGINE THROTTLE BEGAN TO VIBRATE AT 1,200 FEET DURING CLIMB-OUT OF IAH. A STRONG VIBRATION WAS REPORTED IN REAR CABIN. THE NR 3 ENGINE POWER WAS REDUCED, BUT THE VIBRATION CONTINUED. A LOUD BANG ACCOMPANIED BY NR 3 ENGINE SHUTDOWN OCCURRED AS ENGINE POWER WAS ADDED TO RESUME CLIMB. THE AIRCRAFT WAS RETURNED TO IAH WHERE IT LANDED WITHOUT INCIDENT. THE NR 3 ENGINE WAS REMOVED AND REPLACED. THE SDR WILL REMAIN OPEN FOR PART INFORMATION EPNDING INVESTIGATION. (X)