What was found
AT CRUISE THE PILOT NOTICED THE HORIZONTAL PRIMARY TRIM FAIL LIGHT AND SWITCHED TO STAND-BY TRIM BUT THE TRIM SYSTEM WOULD NOT MOVE, THE PILOT IN COMMAND CONTACTED CENTER AND INFORMED CENTER HE HAD AN EMERGENCY AND WANTED TO CHANGE HIS AIRPORT TO ONE THAT HAD 9,000 FEET OR MORE BUT AT 10,000 FEET THE TRIM SYSTEM STARTED WORKING CORRECTLY SO THE CREW INFORMED CENTER THAT THEY NO LONGER HAD A PROBLEM AND LANDED AT KADS WITH NO PROBLEMS. THE TRIM SYSTEM WAS TESTED SEVERAL TIMES AND NO DISCREPANCIES WERE NOTED.