What was found
ON DESCENT THROUGH FL 130 THE CREW REPORTED THE LEFT ENGINE POWER ROLLED BACK FOLLOWED BY A LOUD POP SOUND.ALL INDICATION ON THE MFD ENGINE PARAMETERS INDICATED NORMAL. THE ENGINE WAS SECURED AND THE FLIGHT DIVERTED TO NORTH TEXAS REGIONAL AIRPORT (KGYI). FURTHER EXAMINATION BY MAINTENANCE FOUND THAT THE POWER TURBINE SECOND STAGE BLADES HAD LIBERATED, FURTHER THE PROPPELLER TURNED FREELY. THE REDUCTION GEAR BOX CHIP COLLECTOR WAS REMOVED AND FOUND TO BE COVERED IN METAL FRAGMENTS. NOTE: THE ENGINE WILL BE SENT TO PRATT PLANT 5 FOR ANALYISS AND INVESTIGATION AS TO THE CAUSE .