B737-300 aircraft has an uncommanded roll during departure.

Attributes
ACN	329615
Time
Date	199512
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : dca
State Reference	DC
Altitude	msl bound lower : 6000 msl bound upper : 6000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : dca tower : teb
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	climbout : intermediate altitude
Route In Use	approach : visual
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : cfi pilot : flight engineer
Experience	flight time last 90 days : 240 flight time total : 10000 flight time type : 8500
ASRS Report	329615
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : overcame equipment problem flight crew : regained aircraft control flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

At approximately 6000 ft during climb out, during a slow rollout to left, the right wing suddenly dropped about 5 degrees, I noticed the yaw damper had deflected about 1 bar-width to the right. After it centered, flight continued normally for a few mins and then yaw damper pulsed again to the right 1 bar-width, again causing a small, but definite roll to the right. The roll was easy to control. In general I found the aircraft a bit stiff to roll to the left compared to rolls to right. The yaw damper typically worked in opposition to the direction of the roll, ie, as the aircraft rolled right, the yaw damper usually displaced to the left and vice versa. In the two instances cited above, however, the yaw damper pulsed firmly to the right causing a definite rolling tendency. In all cases above, the autoplt was off. Pulsing ceased as soon as yaw damper was turned off.

Original NASA ASRS Text

Title: B737-300 ACFT HAS AN UNCOMMANDED ROLL DURING DEP.

Narrative: AT APPROX 6000 FT DURING CLBOUT, DURING A SLOW ROLLOUT TO L, THE R WING SUDDENLY DROPPED ABOUT 5 DEGS, I NOTICED THE YAW DAMPER HAD DEFLECTED ABOUT 1 BAR-WIDTH TO THE R. AFTER IT CTRED, FLT CONTINUED NORMALLY FOR A FEW MINS AND THEN YAW DAMPER PULSED AGAIN TO THE R 1 BAR-WIDTH, AGAIN CAUSING A SMALL, BUT DEFINITE ROLL TO THE R. THE ROLL WAS EASY TO CTL. IN GENERAL I FOUND THE ACFT A BIT STIFF TO ROLL TO THE L COMPARED TO ROLLS TO R. THE YAW DAMPER TYPICALLY WORKED IN OPPOSITION TO THE DIRECTION OF THE ROLL, IE, AS THE ACFT ROLLED R, THE YAW DAMPER USUALLY DISPLACED TO THE L AND VICE VERSA. IN THE TWO INSTANCES CITED ABOVE, HOWEVER, THE YAW DAMPER PULSED FIRMLY TO THE R CAUSING A DEFINITE ROLLING TENDENCY. IN ALL CASES ABOVE, THE AUTOPLT WAS OFF. PULSING CEASED AS SOON AS YAW DAMPER WAS TURNED OFF.

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.