B737 crew descended below cleared altitude.

Attributes
ACN	467650
Time
Date	200003
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	intersection : wolvs
State Reference	MN
Altitude	msl single value : 5000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	descent : intermediate altitude
Route In Use	arrival : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 12500 flight time type : 3800
ASRS Report	467650
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial pilot : multi engine
Events
Anomaly	non adherence : published procedure non adherence : company policies non adherence : clearance other anomaly other
Independent Detector	atc equipment other atc equipment : altitude radar readout other controllera
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:

ATC advised us of altimeter setting 29.55. First officer set his altimeter to 29.95. I looked at his and set mine also to 29.95. We discovered the error when ATC asked about our altitude. We were approximately 350 ft lower than assigned due to altimeter being set wrong. I should have looked at ATIS myself instead of trusting first officer.

Original NASA ASRS Text

Title: B737 CREW DSNDED BELOW CLRED ALT.

Narrative: ATC ADVISED US OF ALTIMETER SETTING 29.55. FO SET HIS ALTIMETER TO 29.95. I LOOKED AT HIS AND SET MINE ALSO TO 29.95. WE DISCOVERED THE ERROR WHEN ATC ASKED ABOUT OUR ALT. WE WERE APPROX 350 FT LOWER THAN ASSIGNED DUE TO ALTIMETER BEING SET WRONG. I SHOULD HAVE LOOKED AT ATIS MYSELF INSTEAD OF TRUSTING FO.

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.