Altitude overshoot over dxo VOR.

Attributes
ACN	493880
Time
Date	200011
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : dxo.vor
State Reference	MI
Altitude	msl bound lower : 10700 msl bound upper : 12000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : d21.tracon
Operator	common carrier : air carrier
Make Model Name	DC-9 30
Operating Under FAR Part	Part 121
Flight Phase	descent : vacating altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : cfi pilot : multi engine pilot : atp pilot : instrument
Experience	flight time last 90 days : 180 flight time total : 17000 flight time type : 9500
ASRS Report	493880
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : instrument pilot : commercial
Events
Anomaly	altitude deviation : overshoot non adherence : clearance
Independent Detector	aircraft equipment : altitude alert 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:

First officer flying on autoplt. ATC cleared us from 12000 ft to 11000 ft. First officer descended at about 500 FPM. I was somehow distraction and looked up when I heard the altitude alerter sound and saw us descending 300 ft below assigned altitude. I immediately disconnected autoplt and returned us to 11000 ft. I don't believe there was a traffic conflict because controller cleared us to 7000 ft. I have learned 1000 ft altitude changes can be the most dangerous, as there is not altitude awareness calls by the PNF. The rate of descent or climbs are very slow and can foster complacency.

Original NASA ASRS Text

Title: ALT OVERSHOOT OVER DXO VOR.

Narrative: FO FLYING ON AUTOPLT. ATC CLRED US FROM 12000 FT TO 11000 FT. FO DSNDED AT ABOUT 500 FPM. I WAS SOMEHOW DISTR AND LOOKED UP WHEN I HEARD THE ALT ALERTER SOUND AND SAW US DSNDING 300 FT BELOW ASSIGNED ALT. I IMMEDIATELY DISCONNECTED AUTOPLT AND RETURNED US TO 11000 FT. I DON'T BELIEVE THERE WAS A TFC CONFLICT BECAUSE CTLR CLRED US TO 7000 FT. I HAVE LEARNED 1000 FT ALT CHANGES CAN BE THE MOST DANGEROUS, AS THERE IS NOT ALT AWARENESS CALLS BY THE PNF. THE RATE OF DSCNT OR CLBS ARE VERY SLOW AND CAN FOSTER COMPLACENCY.

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.