Narrative:

Air carrier X during IMC cruise at FL290 approaching the gordansville VOR (gve), for unknown reasons, both pitch trim system disengaged causing the autoplt to disengage also. The aircraft started to climb and the captain immediately grabbed the yoke and initiated corrective action. The aircraft reversed the climb at approximately 29250 ft. As the descent was initiated, the TCASII gave an RA and 'monitor vertical speed.' the lowest altitude, as we passed through FL290 in an attempt to level the aircraft, was 28800 ft. As we received the 'monitor vertical speed,' I heard an air carrier Y aircraft say he left FL280 because of an RA. This, in turn, caused an air carrier Z to vacate his assigned altitude of FL270. Could the TCASII been more of a hinderance in this case? What about 'analyzing the situation.' supplemental information from acn 267714: air carrier X, while cruising at FL290 approaching gve, the autoplt automatic-disconnected and the aircraft climbed 200-250 ft. While attempting to hand fly back to altitude, the aircraft descended to approximately 28900 ft and a TCASII RA began to monitor vertical speed. Both pitch trim controls were found to be 'off' and were reselected 'on.' loss of pitch trim, momentarily, made for erratic manual flight and probably caused the autoplt malfunction. Our RA may have caused lower aircraft to descend. Supplemental information from acn 267720: air carrier X at FL290 dropped 200 ft (autoplt malfunction). Air carrier Y at FL280 got RA and started down. Air carrier Z at FL270 got RA and started down.

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Original NASA ASRS Text

Title: 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.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.