Medium large transport flight crew in descent has no alarm from altitude alert, descends below assig...

Attributes
ACN	323050
Time
Date	199512
Day	Mon
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : atl
State Reference	GA
Altitude	msl bound lower : 10800 msl bound upper : 11000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : atl
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : commercial pilot : instrument
Experience	flight time last 90 days : 190 flight time total : 20000 flight time type : 4200
ASRS Report	323050
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	altitude deviation : overshoot
Independent Detector	other controllera
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	other

Narrative:

Atl approach cleared us from 14000 ft to 11000 ft. Passing through 12000 ft, approach gave us a vector 20 degrees left of course and asked if we had traffic off our right side. The autoplt was flying the aircraft and failed to capture the assigned altitude. The aircraft descended approximately 200 ft below 11000 ft (did not receive an altitude warning), before the autoplt could be disengaged and hand flown back up to 11000 ft. The flight was continued on to atl without further incident.

Original NASA ASRS Text

Title: MLG FLC IN DSCNT HAS NO ALARM FROM ALT ALERT, DSNDS BELOW ASSIGNED ALT.

Narrative: ATL APCH CLRED US FROM 14000 FT TO 11000 FT. PASSING THROUGH 12000 FT, APCH GAVE US A VECTOR 20 DEGS L OF COURSE AND ASKED IF WE HAD TFC OFF OUR R SIDE. THE AUTOPLT WAS FLYING THE ACFT AND FAILED TO CAPTURE THE ASSIGNED ALT. THE ACFT DSNDED APPROX 200 FT BELOW 11000 FT (DID NOT RECEIVE AN ALT WARNING), BEFORE THE AUTOPLT COULD BE DISENGAGED AND HAND FLOWN BACK UP TO 11000 FT. THE FLT WAS CONTINUED ON TO ATL WITHOUT FURTHER INCIDENT.

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.

Medium large transport flight crew in descent has no alarm from altitude alert, descends below assigned altitude.