An air carrier flight crew flying a B737-300 from clt fails to level off at assigned altitude.

Attributes
ACN	458200
Time
Date	199912
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	intersection : haray
State Reference	NC
Altitude	msl bound lower : 12000 msl bound upper : 12300
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : clt.tracon
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	climbout : intermediate altitude
Route In Use	departure sid : hor 1
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 190 flight time total : 16500 flight time type : 4000
ASRS Report	458200
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 210 flight time total : 15000 flight time type : 9000
ASRS Report	458320
Events
Anomaly	altitude deviation : overshoot non adherence : clearance non adherence : company policies non adherence : far
Independent Detector	other controllera other flight crewa other flight crewb
Resolutory Action	controller : provided flight assist flight crew : returned to assigned altitude
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

On climb out on SID, we were cleared to 12000 ft by departure control. As PF, I thought I had engaged autoplt, but as I saw us approaching assigned altitude of 12000 ft MSL, I noticed that aircraft was not leveling off. I went to hand fly and disconnect autoplt, but found it was not engaged. I stopped aircraft at 12300 ft, and went back down to 12000 ft. Controller 'reminded' us we were cleared only to 12000 ft. No other comments were made by us or controller. Apparently the aircraft was trimmed well enough to hold heading and climb rate, so I didn't note it until aircraft approached 12000 ft. No conflict with another aircraft was noted.

Original NASA ASRS Text

Title: AN ACR FLC FLYING A B737-300 FROM CLT FAILS TO LEVEL OFF AT ASSIGNED ALT.

Narrative: ON CLBOUT ON SID, WE WERE CLRED TO 12000 FT BY DEP CTL. AS PF, I THOUGHT I HAD ENGAGED AUTOPLT, BUT AS I SAW US APCHING ASSIGNED ALT OF 12000 FT MSL, I NOTICED THAT ACFT WAS NOT LEVELING OFF. I WENT TO HAND FLY AND DISCONNECT AUTOPLT, BUT FOUND IT WAS NOT ENGAGED. I STOPPED ACFT AT 12300 FT, AND WENT BACK DOWN TO 12000 FT. CTLR 'REMINDED' US WE WERE CLRED ONLY TO 12000 FT. NO OTHER COMMENTS WERE MADE BY US OR CTLR. APPARENTLY THE ACFT WAS TRIMMED WELL ENOUGH TO HOLD HDG AND CLB RATE, SO I DIDN'T NOTE IT UNTIL ACFT APCHED 12000 FT. NO CONFLICT WITH ANOTHER ACFT WAS NOTED.

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.