Flight crew of widebody transport had TCAS alert. Altitude excursion occurred when aircraft was take...

Attributes
ACN	169917
Time
Date	199102
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : gve
State Reference	VA
Altitude	msl bound lower : 28870 msl bound upper : 29000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdc
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : commercial pilot : atp
Experience	flight time last 90 days : 220
ASRS Report	169917
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : instrument pilot : commercial
Experience	flight time last 90 days : 225 flight time total : 6000 flight time type : 1000
ASRS Report	169912
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : regained aircraft control
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Level at FL290, the TCAS displayed TA followed by RA on TCAS screen, with simultaneous aural 'monitor altitude.' my action was to disconnect the autoplt, which was slightly out of trim, nose down. We started a slight descent, which I arrested at 130' below target altitude of FL290. The TCAS aural sounded 'climb.' I climbed back to FL290 and reengaged the autoplt. TCAS RA and aurals quit. This aircraft has extensive history of maintenance problems with #2 transponder TCAS, and altimeter write-ups.

Original NASA ASRS Text

Title: FLT CREW OF WDB HAD TCAS ALERT. ALT EXCURSION OCCURRED WHEN ACFT WAS TAKEN OFF AUTOPLT.

Narrative: LEVEL AT FL290, THE TCAS DISPLAYED TA FOLLOWED BY RA ON TCAS SCREEN, WITH SIMULTANEOUS AURAL 'MONITOR ALT.' MY ACTION WAS TO DISCONNECT THE AUTOPLT, WHICH WAS SLIGHTLY OUT OF TRIM, NOSE DOWN. WE STARTED A SLIGHT DSNT, WHICH I ARRESTED AT 130' BELOW TARGET ALT OF FL290. THE TCAS AURAL SOUNDED 'CLB.' I CLBED BACK TO FL290 AND REENGAGED THE AUTOPLT. TCAS RA AND AURALS QUIT. THIS ACFT HAS EXTENSIVE HISTORY OF MAINT PROBS WITH #2 XPONDER TCAS, AND ALTIMETER WRITE-UPS.

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.

Flight crew of widebody transport had TCAS alert. Altitude excursion occurred when aircraft was taken off autoplt.