Autoplt did not level the aircraft at assigned altitude.

Attributes
ACN	143261
Time
Date	199004
Day	Thu
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : tpa
State Reference	FL
Altitude	msl bound lower : 12000 msl bound upper : 12300
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : tpa tower : mdw
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	climbout : initial cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : commercial pilot : instrument
Experience	flight time last 90 days : 250 flight time total : 6500 flight time type : 280
ASRS Report	143261
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : commercial pilot : atp
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : overshoot non adherence : clearance
Independent Detector	other controllera other flight crewa
Resolutory Action	flight crew : overcame equipment problem
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation other

Narrative:

With aircraft approaching 12000' (assigned altitude), captain engaged autoplt and observed altitude capture feature was armed. However, the aircraft continued to climb through 12000' on autoplt at which time the captain disengaged the autoplt and stopped the climb at 12300', and immediately descended back to 12000'. When queried by departure control, we reaffirmed the assigned 12000'. The autoplt is deficient in capturing armed altitudes, and should be modified to prevent this type of problem.

Original NASA ASRS Text

Title: AUTOPLT DID NOT LEVEL THE ACFT AT ASSIGNED ALT.

Narrative: WITH ACFT APCHING 12000' (ASSIGNED ALT), CAPT ENGAGED AUTOPLT AND OBSERVED ALT CAPTURE FEATURE WAS ARMED. HOWEVER, THE ACFT CONTINUED TO CLB THROUGH 12000' ON AUTOPLT AT WHICH TIME THE CAPT DISENGAGED THE AUTOPLT AND STOPPED THE CLB AT 12300', AND IMMEDIATELY DSNDED BACK TO 12000'. WHEN QUERIED BY DEP CTL, WE REAFFIRMED THE ASSIGNED 12000'. THE AUTOPLT IS DEFICIENT IN CAPTURING ARMED ALTS, AND SHOULD BE MODIFIED TO PREVENT THIS TYPE OF PROB.

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.