Yaw damper fails during climb. Flight crew begins descent before advising ATC.

Attributes
ACN	143857
Time
Date	199004
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : tul
State Reference	OK
Altitude	msl bound lower : 27000 msl bound upper : 27000
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zkc tower : dca
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	climbout : intermediate altitude descent other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : atp pilot : commercial pilot : instrument
Experience	flight time last 90 days : 200 flight time total : 10000 flight time type : 1200
ASRS Report	143857
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : flight engineer pilot : instrument
Experience	flight time last 90 days : 200 flight time total : 5000
ASRS Report	143743
Events
Anomaly	aircraft equipment problem : critical altitude deviation : excursion from assigned altitude non adherence : far non adherence : clearance
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	none taken : unable
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Climbing through FL270, experienced unwanted yaw inputs. We started a gentle descent and speed reduction then requested and received permission to descend to FL240. We leveled of at FL240 (250 KTS) and turned off our upper yaw damper. After consulting company tech we continued to destination (ord).

Original NASA ASRS Text

Title: YAW DAMPER FAILS DURING CLIMB. FLT CREW BEGINS DESCENT BEFORE ADVISING ATC.

Narrative: CLBING THROUGH FL270, EXPERIENCED UNWANTED YAW INPUTS. WE STARTED A GENTLE DSNT AND SPD REDUCTION THEN REQUESTED AND RECEIVED PERMISSION TO DSND TO FL240. WE LEVELED OF AT FL240 (250 KTS) AND TURNED OFF OUR UPPER YAW DAMPER. AFTER CONSULTING COMPANY TECH WE CONTINUED TO DEST (ORD).

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.