A B767 in climb at 16000 ft diverted due to EICAS flight control warnings with autoplt engage failur...

Attributes
ACN	517141
Time
Date	200107
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	msl single value : 16000
Aircraft 1
Controlling Facilities	artcc : zzz.artcc tower : zzz.tower
Make Model Name	B767 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time type : 3020
ASRS Report	517141
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : rudder trim indicator other flight crewa
Resolutory Action	flight crew : diverted to another airport
Consequence	other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

Copilot, hand flying, trimmed aircraft -- attempted to engage center autoplt in command mode. Autoplt disconnect light and siren warning, aileron lockout EICAS and rudder ratio EICAS, and rudder trim went from 5 units right to zero units for trimmed flight. Copilot flew and talked with ATC while I ran the procedures, talked with dispatch and maintenance, flight attendants and passenger. We tried to determine the extent of any problems talking with maintenance. We were not able to engage any autoplt or clear the EICAS cautions. An uneventful landing was made at ZZZ. Maintenance was able to fix the aileron and rudder ratio problems, but could not explain the abrupt change in rudder trim and the flight was canceled. Copilot stated he was engaging the autoplt and proceeded to push the center autoplt command switch. When he pushed the switch, the autoplt disconnect warning and siren sounded, rudder ratio light and EICAS, and the aileron lockout light and EICAS. The aircraft at this point required approximately 30 degrees of left aileron to maintain straight flight. I advised ATC that we had a problem and would level at 17000 ft. He asked what the nature of the problem ws and I stated I would get back to him in a short time.

Original NASA ASRS Text

Title: A B767 IN CLB AT 16000 FT DIVERTED DUE TO EICAS FLT CTL WARNINGS WITH AUTOPLT ENGAGE FAILURE AND UNCOMMANDED RUDDER TRIM MOVEMENT. CAUSE OF UNCOMMANDED RUDDER TRIM MOVEMENT UNKNOWN.

Narrative: COPLT, HAND FLYING, TRIMMED ACFT -- ATTEMPTED TO ENGAGE CTR AUTOPLT IN COMMAND MODE. AUTOPLT DISCONNECT LIGHT AND SIREN WARNING, AILERON LOCKOUT EICAS AND RUDDER RATIO EICAS, AND RUDDER TRIM WENT FROM 5 UNITS R TO ZERO UNITS FOR TRIMMED FLT. COPLT FLEW AND TALKED WITH ATC WHILE I RAN THE PROCS, TALKED WITH DISPATCH AND MAINT, FLT ATTENDANTS AND PAX. WE TRIED TO DETERMINE THE EXTENT OF ANY PROBS TALKING WITH MAINT. WE WERE NOT ABLE TO ENGAGE ANY AUTOPLT OR CLR THE EICAS CAUTIONS. AN UNEVENTFUL LNDG WAS MADE AT ZZZ. MAINT WAS ABLE TO FIX THE AILERON AND RUDDER RATIO PROBS, BUT COULD NOT EXPLAIN THE ABRUPT CHANGE IN RUDDER TRIM AND THE FLT WAS CANCELED. COPLT STATED HE WAS ENGAGING THE AUTOPLT AND PROCEEDED TO PUSH THE CTR AUTOPLT COMMAND SWITCH. WHEN HE PUSHED THE SWITCH, THE AUTOPLT DISCONNECT WARNING AND SIREN SOUNDED, RUDDER RATIO LIGHT AND EICAS, AND THE AILERON LOCKOUT LIGHT AND EICAS. THE ACFT AT THIS POINT REQUIRED APPROX 30 DEGS OF L AILERON TO MAINTAIN STRAIGHT FLT. I ADVISED ATC THAT WE HAD A PROB AND WOULD LEVEL AT 17000 FT. HE ASKED WHAT THE NATURE OF THE PROB WS AND I STATED I WOULD GET BACK TO HIM IN A SHORT TIME.

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.

A B767 in climb at 16000 ft diverted due to EICAS flight control warnings with autoplt engage failure and uncommanded rudder trim movement. Cause of uncommanded rudder trim movement unknown.