EMB135 FLT CREW EXPERIENCED BACKUP TRIM SYS FAILURE.

Narrative

CLBING THROUGH FL240; ENCOUNTERED PITCH TRIM MAIN FAILURE ON EICAS. ACCOMPLISHED AOM PROC; WHICH IS NOT CLR. ENCOUNTERED BACKUP TRIM FAILURE AS A RESULT OF ACTUATING BACKUP TRIM SWITCH. FOLLOWED APPROPRIATE BACKUP TRIM FAILURE CHKLIST; BUT DID NOT RECEIVE EICAS WARNING OF SUCH -- TRIM SYS SENSED SWITCH ACTUATION; BUT WOULD NOT MOVE STABILIZER. RE-RAN ENTIRE AOM CHKLIST AND ENDED UP CLRING THE FAULT BUT STILL HAD INTERMITTENT BACKUP TRIM ACTUATION IN NOSE DOWN DIRECTION. CONTACTED ATC TO ADVISE OF TRIM FAILURE; BUT DID NOT DECLARE EMER AS THE ISSUE CLRED ITSELF UP. RECEIVED EICAS WARNING THAT LED US THROUGH THE CHKLIST IN THE AOM DETERMINING THE FAILURE OF THE BACKUP SYS. REACTION: FOLLOWED THROUGH AOM CHKLIST A TOTAL OF 3 TIMES. 1) UPON RECEIPT OF THE MASTER WARNING MESSAGE ON THE EICAS. 2) UPON DISCOVERY OF THE BACKUP TRIM FAILURE. 3) RE-READ THROUGH ENTIRE PROC AS THE CHKLIST IS NOT ORGANIZED IN A COMPREHENSIVE WAY. SUGGESTIONS: TRIM FAILURE CHKLIST CALLS FOR THE DEACTIVATION OF THE MAIN AND/OR BACKUP TRIM SYS; WHICH PRECLUDES ANY FORM OF TROUBLESHOOTING STIPULATED LATER IN THE CHKLIST.