An altimeter not set to qnh when beginning descent from FL180 results in an altitude overshoot.

Attributes
ACN	510390
Time
Date	200105
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : cyvr.airport
State Reference	BC
Altitude	msl bound lower : 7500 msl bound upper : 8000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B737 Undifferentiated or Other Model
Flight Phase	descent : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : commercial pilot : instrument pilot : multi engine
Experience	flight time last 90 days : 210 flight time total : 7000 flight time type : 2100
ASRS Report	510390
Person 2
Qualification	pilot : instrument pilot : multi engine pilot : commercial pilot : atp
Experience	flight time last 90 days : 210 flight time total : 7000 flight time type : 2100
ASRS Report	510390
Events
Anomaly	altitude deviation : overshoot non adherence : clearance non adherence : far
Resolutory Action	flight crew : became reoriented 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:

2 pilot crew failed to remember to reset aircraft altimeters from cruise setting of 29.92 to arrival setting at vancouver of 30.41. This resulted in our leveling off at 7500 ft MSL instead of assigned altitude of 8000 ft MSL. Part of the reason for our failure was our unusual cruise altitude of FL180. Normally, we descend from a much higher altitude (mid FL300's) and change our altimeter setting about 1/2 way through our descent. This habit pattern caused us to notice our incorrectly set altimeters just after leveling off at 7500 ft MSL (500 ft low).

Original NASA ASRS Text

Title: AN ALTIMETER NOT SET TO QNH WHEN BEGINNING DSCNT FROM FL180 RESULTS IN AN ALT OVERSHOOT.

Narrative: 2 PLT CREW FAILED TO REMEMBER TO RESET ACFT ALTIMETERS FROM CRUISE SETTING OF 29.92 TO ARR SETTING AT VANCOUVER OF 30.41. THIS RESULTED IN OUR LEVELING OFF AT 7500 FT MSL INSTEAD OF ASSIGNED ALT OF 8000 FT MSL. PART OF THE REASON FOR OUR FAILURE WAS OUR UNUSUAL CRUISE ALT OF FL180. NORMALLY, WE DSND FROM A MUCH HIGHER ALT (MID FL300'S) AND CHANGE OUR ALTIMETER SETTING ABOUT 1/2 WAY THROUGH OUR DSCNT. THIS HABIT PATTERN CAUSED US TO NOTICE OUR INCORRECTLY SET ALTIMETERS JUST AFTER LEVELING OFF AT 7500 FT MSL (500 FT LOW).

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.