What was found
(CAN) DURING CLIMB, PILOT EXPERIENCED A SLIGHT THUMP THROUGH ELEVATOR CONTROL SYSTEM, AND A MINOR VIBRATION WHICH STOPPED WHEN LEVEL FLIGHT WAS ACHIEVED. THE FLIGHT WAS CONTINUED TO DESTINATION WHERE MAINTENANCE WAS AVAILABLE. THE PILOT NOTED THAT MORE ELEVATOR TRIM WAS NEEDED TO ACHIEVE LEVEL FLIGHT. AFTER AN UNEVENTFUL LANDING, MAINTENANCE INVESTIGATION REVEALED THAT THE LT ELEVATOR TRIM ROD HAD FAILED AT THE AFT END IN THE STEEL THREADED SECTION. CLOSE EXAMINATION OF THE BREAK REVEALED THAT THE ROD HAD BEEN BENT AND COLD STRAIGHTENED AT SOME POINT, INITIATING A CRACK. THE ROD WAS REPLACED AND THE AIRCRAFT WAS RETURNED TO SERVICE. THE AIRCRAFT IS OPERATING IN A CORROSIVE ENVIRONMENT.