Altitude deviation altitude overshot by an MD80 flight crew when the altitude alerter is knocked off...

Attributes
ACN	508490
Time
Date	200104
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : sfo.airport
State Reference	CA
Altitude	msl bound lower : 11200 msl bound upper : 12000
Environment
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	MD-80 Series (DC-9-80) Undifferentiated or Other Model
Flight Plan	IFR
Aircraft 2
Flight Phase	descent : approach
Route In Use	arrival star : golden gate
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	508490
Events
Anomaly	altitude deviation : crossing restriction not met altitude deviation : overshoot non adherence : clearance non adherence : published procedure
Resolutory Action	controller : issued advisory controller : issued new clearance flight crew : became reoriented
Consequence	other
Supplementary
Problem Areas	Environmental Factor Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Location: duxby intersection, 6 NM northwest of sfo. Clearance was given to cross duxby intersection at 12000 ft on the golden gate 4 arrival to sjc. Somehow on descent, the altitude select knob was hit and the arming altitude was reset to 10000 ft. I missed that in the descent. Upon going through 11200 ft, the controller asked us what altitude had we been cleared to. I responded with 10000 ft. He asked if we could level at 11000 ft, and we did. I also asked if we had created a conflict. The controller responded with a definite 'no.' he handed us to bay approach and we continued the flight with no further incidence. Upon further study of the arrival plate, indeed you are supposed to cross duxby intersection at 12000 ft. The first officer recalls me setting and arming the altitude and him confirming it. The shocker is that we both missed it somehow after he hit the altitude arm wheel and set 10000 ft by accident, on the descent and then never bothered to look at the altitude arm window again. Granted, we were both tired from the early sign-in at XA40 and we both had a terrible night's sleep the night prior. Hopefully no matter how tired I am, I'll keep checking and doublechking things on descent.

Original NASA ASRS Text

Title: ALTDEV ALT OVERSHOT BY AN MD80 FLT CREW WHEN THE ALT ALERTER IS KNOCKED OFF THE PRESET XING ALT NW OF SFO, CA.

Narrative: LOCATION: DUXBY INTXN, 6 NM NW OF SFO. CLRNC WAS GIVEN TO CROSS DUXBY INTXN AT 12000 FT ON THE GOLDEN GATE 4 ARR TO SJC. SOMEHOW ON DSCNT, THE ALT SELECT KNOB WAS HIT AND THE ARMING ALT WAS RESET TO 10000 FT. I MISSED THAT IN THE DSCNT. UPON GOING THROUGH 11200 FT, THE CTLR ASKED US WHAT ALT HAD WE BEEN CLRED TO. I RESPONDED WITH 10000 FT. HE ASKED IF WE COULD LEVEL AT 11000 FT, AND WE DID. I ALSO ASKED IF WE HAD CREATED A CONFLICT. THE CTLR RESPONDED WITH A DEFINITE 'NO.' HE HANDED US TO BAY APCH AND WE CONTINUED THE FLT WITH NO FURTHER INCIDENCE. UPON FURTHER STUDY OF THE ARR PLATE, INDEED YOU ARE SUPPOSED TO CROSS DUXBY INTXN AT 12000 FT. THE FO RECALLS ME SETTING AND ARMING THE ALT AND HIM CONFIRMING IT. THE SHOCKER IS THAT WE BOTH MISSED IT SOMEHOW AFTER HE HIT THE ALT ARM WHEEL AND SET 10000 FT BY ACCIDENT, ON THE DSCNT AND THEN NEVER BOTHERED TO LOOK AT THE ALT ARM WINDOW AGAIN. GRANTED, WE WERE BOTH TIRED FROM THE EARLY SIGN-IN AT XA40 AND WE BOTH HAD A TERRIBLE NIGHT'S SLEEP THE NIGHT PRIOR. HOPEFULLY NO MATTER HOW TIRED I AM, I'LL KEEP CHKING AND DOUBLECHKING THINGS ON DSCNT.

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.

Altitude deviation altitude overshot by an MD80 flight crew when the altitude alerter is knocked off the preset crossing altitude northwest of sfo, ca.