Medium large transport cleared to descend to 12000' overshoots to 11300' before correcting.

Attributes
ACN	152053
Time
Date	199007
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : sac airport : smf
State Reference	CA
Altitude	msl bound lower : 11300 msl bound upper : 12000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zoa
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	arrival other arrival star : star
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : cfi pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 150 flight time total : 8500 flight time type : 1200
ASRS Report	152053
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : overshoot conflict : airborne less severe non adherence : clearance non adherence : published procedure non adherence : required legal separation
Independent Detector	other controllera
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	faa : investigated
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

En route to smf using autoplt (with automatic level off feature) we were issued descent clearance to 12000. Ctrl questioned our altitude as aircraft descended to about 11300; as our attention was diverted outside for previous traffic call out. 11000 was set in altitude alert window instead of 12000, either inadvertently or malfunction. Perhaps long flight time day, traffic call out caused us to miss double check of altitude assignment against altitude alert window setting. Callback conversation with reporter revealed the following: they had been cleared for the wraps 4 arrival. In anticipation of crossing sac VOR at 11000', first officer entered it in the FMC to get an idea about where he would be starting his descent. He forgot to take it out and when they were cleared to 12000' the FMC still had 11000' loaded in it. Altitude alert was also set to 11000' and reporter could not explain why.

Original NASA ASRS Text

Title: MLG CLEARED TO DESCEND TO 12000' OVERSHOOTS TO 11300' BEFORE CORRECTING.

Narrative: ENRTE TO SMF USING AUTOPLT (WITH AUTO LEVEL OFF FEATURE) WE WERE ISSUED DSNT CLRNC TO 12000. CTRL QUESTIONED OUR ALT AS ACFT DSNDED TO ABOUT 11300; AS OUR ATTN WAS DIVERTED OUTSIDE FOR PREVIOUS TFC CALL OUT. 11000 WAS SET IN ALT ALERT WINDOW INSTEAD OF 12000, EITHER INADVERTENTLY OR MALFUNCTION. PERHAPS LONG FLT TIME DAY, TFC CALL OUT CAUSED US TO MISS DOUBLE CHK OF ALT ASSIGNMENT AGAINST ALT ALERT WINDOW SETTING. CALLBACK CONVERSATION WITH REPORTER REVEALED THE FOLLOWING: THEY HAD BEEN CLRED FOR THE WRAPS 4 ARR. IN ANTICIPATION OF XING SAC VOR AT 11000', F/O ENTERED IT IN THE FMC TO GET AN IDEA ABOUT WHERE HE WOULD BE STARTING HIS DSNT. HE FORGOT TO TAKE IT OUT AND WHEN THEY WERE CLRED TO 12000' THE FMC STILL HAD 11000' LOADED IN IT. ALT ALERT WAS ALSO SET TO 11000' AND RPTR COULD NOT EXPLAIN WHY.

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.