Air carrier at cruise has control problem. Makes precautionary landing.

Attributes
ACN	179427
Time
Date	199105
Day	Thu
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : har
State Reference	PA
Altitude	msl bound lower : 22000 msl bound upper : 22000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zny
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 24 flight time total : 11640 flight time type : 8000
ASRS Report	179427
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : instrument pilot : commercial
Experience	flight time last 90 days : 60 flight time total : 7500 flight time type : 60
ASRS Report	179423
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : declared emergency none taken : unable
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

Shortly after level-off at FL220, I advised the first officer that I would be going aft to use the rest facs. Upon arrival to the lav, I sensed an abnormal yaw from the aircraft and immediately returned to my cockpit seat. The first officer was having difficulty maintaining straight and level flight. I took control of the aircraft and diagnosed the problem as being associated with either the rudder and/or yaw damper system. The checklist for abnormal rudder control was completed, resulting in a return to normal aircraft control. System control was advised and the F/a's were briefed to stay in their seats. Priority handling direct to pit was requested from ATC. An uneventful landing in pit was accomplished using manual rudder procedures. An appropriate log book entry was made upon arrival at the gate.

Original NASA ASRS Text

Title: ACR AT CRUISE HAS CTL PROBLEM. MAKES PRECAUTIONARY LNDG.

Narrative: SHORTLY AFTER LEVEL-OFF AT FL220, I ADVISED THE F/O THAT I WOULD BE GOING AFT TO USE THE REST FACS. UPON ARR TO THE LAV, I SENSED AN ABNORMAL YAW FROM THE ACFT AND IMMEDIATELY RETURNED TO MY COCKPIT SEAT. THE F/O WAS HAVING DIFFICULTY MAINTAINING STRAIGHT AND LEVEL FLT. I TOOK CTL OF THE ACFT AND DIAGNOSED THE PROB AS BEING ASSOCIATED WITH EITHER THE RUDDER AND/OR YAW DAMPER SYS. THE CHKLIST FOR ABNORMAL RUDDER CTL WAS COMPLETED, RESULTING IN A RETURN TO NORMAL ACFT CTL. SYS CTL WAS ADVISED AND THE F/A'S WERE BRIEFED TO STAY IN THEIR SEATS. PRIORITY HANDLING DIRECT TO PIT WAS REQUESTED FROM ATC. AN UNEVENTFUL LNDG IN PIT WAS ACCOMPLISHED USING MANUAL RUDDER PROCS. AN APPROPRIATE LOG BOOK ENTRY WAS MADE UPON ARR AT THE GATE.

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.