A B737-700 in cruise at FL390 declared an emergency due to rudder trim trimming opposite of input. T...

Attributes
ACN	663044
Time
Date	200506
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	msl single value : 39000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zzz1.artcc
Operator	common carrier : air carrier
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Experience	flight time last 90 days : 232
ASRS Report	663044
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Experience	flight time last 90 days : 180 flight time total : 5000 flight time type : 1300
ASRS Report	663042
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	aircraft equipment other aircraft equipment : primary flight instrument other flight crewa other flight crewb
Resolutory Action	flight crew : declared emergency flight crew : diverted to another airport flight crew : overcame equipment problem
Consequence	other other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

At cruise attempted to trim aircraft with right rudder trim; no movement. Pulled and reset circuit breaker. Second attempt to trim aircraft resulted in rudder trim moving left with right trim input. Aircraft had two units of left rudder at this time and unable to trim to the right; necessitated manual rudder input for coordinated flight. Pulled circuit breaker; conferred with dispatch and maintenance control and decided to divert to ZZZ. Declared an emergency; landed at 133000 pounds; an overweight landing. Normal landing and taxi to gate. Logbook write ups on malfunctioning rudder trim and overweight landing. Callback conversation with reporter revealed the following information: rudder trim was used at FL390 and no trim was noted and per the book the circuit breaker was pulled and reset. The rudder now trimmed to the left with right rudder input. An emergency was declared and the flight was diverted with an overweight landing accomplished. Maintenance found the electrical connector on the rudder trim actuator had failed allowing the pins to arc internally. Callback conversation with reporter acn 663042 revealed the following information: in cruise at FL390; the rudder trim did not operate. The circuit breaker was in and not tripped. The breaker was pulled and reset and the trim was operated but with right trim input the actuator trimmed to left rudder. The rudder trim would not trim right. The reporter indicated that this could be a serious problem if the left engine were to fail.

Original NASA ASRS Text

Title: A B737-700 IN CRUISE AT FL390 DECLARED AN EMER DUE TO RUDDER TRIM TRIMMING OPPOSITE OF INPUT. TRIM L GET R TRIM; WHICH WAS CAUSED BY FAILED CONNECTOR ON TRIM ACTUATOR.

Narrative: AT CRUISE ATTEMPTED TO TRIM ACFT WITH R RUDDER TRIM; NO MOVEMENT. PULLED AND RESET CB. SECOND ATTEMPT TO TRIM ACFT RESULTED IN RUDDER TRIM MOVING L WITH R TRIM INPUT. ACFT HAD TWO UNITS OF L RUDDER AT THIS TIME AND UNABLE TO TRIM TO THE R; NECESSITATED MANUAL RUDDER INPUT FOR COORDINATED FLT. PULLED CB; CONFERRED WITH DISPATCH AND MAINT CTL AND DECIDED TO DIVERT TO ZZZ. DECLARED AN EMER; LANDED AT 133000 POUNDS; AN OVERWEIGHT LNDG. NORMAL LNDG AND TAXI TO GATE. LOGBOOK WRITE UPS ON MALFUNCTIONING RUDDER TRIM AND OVERWEIGHT LNDG. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RUDDER TRIM WAS USED AT FL390 AND NO TRIM WAS NOTED AND PER THE BOOK THE CB WAS PULLED AND RESET. THE RUDDER NOW TRIMMED TO THE L WITH R RUDDER INPUT. AN EMER WAS DECLARED AND THE FLT WAS DIVERTED WITH AN OVERWEIGHT LNDG ACCOMPLISHED. MAINT FOUND THE ELECTRICAL CONNECTOR ON THE RUDDER TRIM ACTUATOR HAD FAILED ALLOWING THE PINS TO ARC INTERNALLY. CALLBACK CONVERSATION WITH RPTR ACN 663042 REVEALED THE FOLLOWING INFO: IN CRUISE AT FL390; THE RUDDER TRIM DID NOT OPERATE. THE CB WAS IN AND NOT TRIPPED. THE BREAKER WAS PULLED AND RESET AND THE TRIM WAS OPERATED BUT WITH R TRIM INPUT THE ACTUATOR TRIMMED TO L RUDDER. THE RUDDER TRIM WOULD NOT TRIM R. THE RPTR INDICATED THAT THIS COULD BE A SERIOUS PROBLEM IF THE L ENG WERE TO FAIL.

Data retrieved from NASA's ASRS site as of January 2009 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 B737-700 in cruise at FL390 declared an emergency due to rudder trim trimming opposite of input. Trim left get right trim; which was caused by failed connector on trim actuator.