Air carrier descends below assigned altitude over fim.

Attributes
ACN	457450
Time
Date	199912
Day	Sat
Local Time Of Day	1201 To 1800
Place
State Reference	CA
Altitude	msl bound lower : 11600 msl bound upper : 12000
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : sct.tracon
Operator	common carrier : air carrier
Make Model Name	MD-80 Super 80
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : multi engine pilot : atp
ASRS Report	457450
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : multi engine pilot : commercial
Events
Anomaly	altitude deviation : overshoot non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	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:

Descending to cross filmore at 12000 ft with the autoplt on, we were given a clearance to 10000 ft and 220 KTS. 10000 ft was set and armed. Descending through 11800 ft I asked the first officer to verify 10000 ft before or after filmore. Socal advises us to maintain 12000 ft until after filmore. Turning the autoplt off descent was stopped at 11600 ft. We returned to 12000 ft.

Original NASA ASRS Text

Title: ACR DSNDS BELOW ASSIGNED ALT OVER FIM.

Narrative: DSNDING TO CROSS FILMORE AT 12000 FT WITH THE AUTOPLT ON, WE WERE GIVEN A CLRNC TO 10000 FT AND 220 KTS. 10000 FT WAS SET AND ARMED. DSNDING THROUGH 11800 FT I ASKED THE FO TO VERIFY 10000 FT BEFORE OR AFTER FILMORE. SOCAL ADVISES US TO MAINTAIN 12000 FT UNTIL AFTER FILMORE. TURNING THE AUTOPLT OFF DSCNT WAS STOPPED AT 11600 FT. WE RETURNED TO 12000 FT.

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.