ACR X ACFT EQUIP PROB AUTOPLT EXCURSION FROM ASSIGNED ALT TCASII RA CAUSED ACR Y AND Z TCASII RA'S DSND. EVASIVE ACTION TAKEN. LTSS.

Narrative

ACR X DURING IMC CRUISE AT FL290 APCHING THE GORDANSVILLE VOR (GVE); FOR UNKNOWN REASONS; BOTH PITCH TRIM SYS DISENGAGED CAUSING THE AUTOPLT TO DISENGAGE ALSO. THE ACFT STARTED TO CLB AND THE CAPT IMMEDIATELY GRABBED THE YOKE AND INITIATED CORRECTIVE ACTION. THE ACFT REVERSED THE CLB AT APPROX 29250 FT. AS THE DSCNT WAS INITIATED; THE TCASII GAVE AN RA AND 'MONITOR VERT SPD.' THE LOWEST ALT; AS WE PASSED THROUGH FL290 IN AN ATTEMPT TO LEVEL THE ACFT; WAS 28800 FT. AS WE RECEIVED THE 'MONITOR VERT SPD;' I HEARD AN ACR Y ACFT SAY HE LEFT FL280 BECAUSE OF AN RA. THIS; IN TURN; CAUSED AN ACR Z TO VACATE HIS ASSIGNED ALT OF FL270. COULD THE TCASII BEEN MORE OF A HINDERANCE IN THIS CASE? WHAT ABOUT 'ANALYZING THE SIT.' SUPPLEMENTAL INFO FROM ACN 267714: ACR X; WHILE CRUISING AT FL290 APCHING GVE; THE AUTOPLT AUTO-DISCONNECTED AND THE ACFT CLBED 200-250 FT. WHILE ATTEMPTING TO HAND FLY BACK TO ALT; THE ACFT DSNDED TO APPROX 28900 FT AND A TCASII RA BEGAN TO MONITOR VERT SPD. BOTH PITCH TRIM CTLS WERE FOUND TO BE 'OFF' AND WERE RESELECTED 'ON.' LOSS OF PITCH TRIM; MOMENTARILY; MADE FOR ERRATIC MANUAL FLT AND PROBABLY CAUSED THE AUTOPLT MALFUNCTION. OUR RA MAY HAVE CAUSED LOWER ACFT TO DSND. SUPPLEMENTAL INFO FROM ACN 267720: ACR X AT FL290 DROPPED 200 FT (AUTOPLT MALFUNCTION). ACR Y AT FL280 GOT RA AND STARTED DOWN. ACR Z AT FL270 GOT RA AND STARTED DOWN.