A CANADAIR CL65 IN CLB BTWN 8000 FT TO FL210 DIVERTED DUE TO LOSS OF STABILIZER NOSE DOWN MANUAL AND AUTOPLT TRIM. CAUSE UNKNOWN.

Narrative

WHILE EXECUTING THE BG3 DEP OFF CVG (YRK TRANSITION); THE FO (WHO WAS THE PF) ASKED FOR HDG MODE AND AUTOPLT ON. THE CAPT PROCEEDED WITH HIS REQUEST AS THE ACFT CAPTURED 8000 FT AND BEGAN A LEVELOFF. WE THEN RECEIVED AUTOPLT TRIM ND; 'E'; AND AUTOPLT PITCH TRIM CAUTION MESSAGES. THE FO FLEW THE PLANE AND GOT THE RADIOS WHILE THE CAPT REFED THE QRH PROCS AND EXECUTED THEM. UPON COMPLETION; THE CAUTION MESSAGES RETURNED. THE CAPT CALLED CVG MAINT AFTER IT WAS DISCOVERED THAT WITH STABILIZER TRIM ARMED #1 AND #2 STILL ENGAGED; NOSE DOWN STABILIZER TRIM WAS INOP. AFTER EXPLAINING THE SIT; THE CAPT AND CVG MAINT CONCLUDED THAT THE FLT SHOULD BE BROUGHT BACK TO CVG AS A PRECAUTIONARY MEASURE. THE CAPT CALLED THE FLT ATTENDANT TO EXPLAIN THE DIVERSION AND HAVE HER DISCONTINUE SVC AND PREPARE THE CABIN FOR A DSCNT AND LNDG IN CVG. THE CAPT MADE A PA TO BRIEF THE PAX OF THE EVENT AND EXPLAIN THAT IT WAS MERELY A PRECAUTIONARY LNDG AND THAT THEY COULD EXPECT A NORMAL DSCNT AND LNDG. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED ON RETURNING WE WERE SWITCHED TO ANOTHER ACFT AND WERE NOT ADVISED OF THE CAUSE OF THE STABILIZER TRIM FAILURE.