What was found
1859Z AT FL 290 ENCOUNTERED SEVERE TURBULENCE. TWO OVER SPEEDS WERE NOTED DURING THE EVENT OVER SPEED WAS APPROXIMATELY 40 KNOTS . OVERALL AIRSPEED LOSS AND GAIN APPROXIMATELY 50 KTS. ALTITUDE LOSS AND GAIN WAS 1000 . FINALLY GOT CONTROL OF THE AIRCRAFT WHEN TURBULENCE LESSENED. DESCENDED TO FL280, TURNED EAST AND EVENTUALLY SOUTH. AFTER DECLARING AN EMERGENCY, WE DUMPED 113,000LBS OF FUEL AND RETURNED TO KIX. INSPECTED SEVERE TURBURANCE INSPECTION AS PER MM05-51-04-2 NO DEFECT FOUND AND PERFORMED AFDS TEST PASSED PER 22-11-00-730-801. A/C OK FOR SVC.