Altitude overshoot during descent toward dtw, mi.

Attributes
ACN	471520
Time
Date	200005
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : dtw.airport
State Reference	MI
Altitude	msl bound lower : 16700 msl bound upper : 17000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zob.artcc
Operator	common carrier : air carrier
Make Model Name	DC-9 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	descent : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : cfi pilot : atp
Experience	flight time last 90 days : 130 flight time total : 11000 flight time type : 5000
ASRS Report	471520
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : commercial pilot : instrument
Events
Anomaly	altitude deviation : overshoot non adherence : clearance
Independent Detector	other controllerb other flight crewa
Resolutory Action	controller : issued advisory 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:

We were descending to 17000 ft. First officer was flying. I made the 2000 ft to go call and the 1000 ft to go call at FL180. We set the altimeters at FL180. The altitude alert sounded at FL180. I looked down to get my approach chart, looked up and we were at 16700 ft. I looked up and said 17! The first officer immediately corrected and pulled up to 17000 ft. The controller queried our altitude and I stated 17000 ft. There was no conflict. Both of us needed to be more alert in the term phase. I didn't expect this and the first officer couldn't explain why this happened.

Original NASA ASRS Text

Title: ALT OVERSHOOT DURING DSCNT TOWARD DTW, MI.

Narrative: WE WERE DSNDING TO 17000 FT. FO WAS FLYING. I MADE THE 2000 FT TO GO CALL AND THE 1000 FT TO GO CALL AT FL180. WE SET THE ALTIMETERS AT FL180. THE ALT ALERT SOUNDED AT FL180. I LOOKED DOWN TO GET MY APCH CHART, LOOKED UP AND WE WERE AT 16700 FT. I LOOKED UP AND SAID 17! THE FO IMMEDIATELY CORRECTED AND PULLED UP TO 17000 FT. THE CTLR QUERIED OUR ALT AND I STATED 17000 FT. THERE WAS NO CONFLICT. BOTH OF US NEEDED TO BE MORE ALERT IN THE TERM PHASE. I DIDN'T EXPECT THIS AND THE FO COULDN'T EXPLAIN WHY THIS HAPPENED.

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.