A320 flight crew thought autoplt was engaged -- it wasn't. They overshot assigned altitude.

Attributes
ACN	496600
Time
Date	200012
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : ord.airport
State Reference	IL
Altitude	agl single value : 0
Environment
Light	Night
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B767 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	ground : taxi
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	496600
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : multi engine pilot : instrument
ASRS Report	496601
Events
Anomaly	non adherence : company policies non adherence : published procedure
Independent Detector	other flight crewa other flight crewb
Resolutory Action	none taken : detected after the fact
Consequence	other
Supplementary
Problem Areas	Flight Crew Human Performance Airport Environmental Factor
Primary Problem	Flight Crew Human Performance

Narrative:

Flight cleared to FL210, crew anticipating further climb and thought autoplt was engaged. We both noticed the aircraft wasn't leveling off and so the PF (first officer) called the deviation and returned the aircraft to FL210 and re-engaged the autoplt. Altitude deviation was 500-600 ft high. Neither of us could be absolutely sure the autoplt #2 FMA was illuminated even though we both remember pushing the autoplt #2 button and announcing autoplt #2 on.

Original NASA ASRS Text

Title: A320 FLC THOUGHT AUTOPLT WAS ENGAGED -- IT WASN'T. THEY OVERSHOT ASSIGNED ALT.

Narrative: FLT CLRED TO FL210, CREW ANTICIPATING FURTHER CLB AND THOUGHT AUTOPLT WAS ENGAGED. WE BOTH NOTICED THE ACFT WASN'T LEVELING OFF AND SO THE PF (FO) CALLED THE DEV AND RETURNED THE ACFT TO FL210 AND RE-ENGAGED THE AUTOPLT. ALTDEV WAS 500-600 FT HIGH. NEITHER OF US COULD BE ABSOLUTELY SURE THE AUTOPLT #2 FMA WAS ILLUMINATED EVEN THOUGH WE BOTH REMEMBER PUSHING THE AUTOPLT #2 BUTTON AND ANNOUNCING AUTOPLT #2 ON.

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.