Small aircraft trainee and instructor penetrated stl class B airspace.

Attributes
ACN	460130
Time
Date	200001
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : t75.tracon
State Reference	MO
Altitude	msl single value : 3500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : instructional
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Fixed Gear
Operating Under FAR Part	Part 91
Navigation In Use	other vortac
Flight Phase	climbout : vacating altitude
Flight Plan	VFR
Person 1
Affiliation	other
Function	flight crew : single pilot instruction : trainee
Qualification	pilot : private
Experience	flight time last 90 days : 25 flight time total : 748 flight time type : 100
ASRS Report	460130
Person 2
Affiliation	other
Function	instruction : instructor oversight : pic
Qualification	pilot : cfi pilot : commercial
Events
Anomaly	airspace violation : entry altitude deviation : overshoot non adherence : published procedure non adherence : far
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to assigned airspace
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We were climbing out of cps northbound. We leveled off at 2500 ft. Class B started at 3000 ft. I noted to my instructor that it took us an awfully long time to climb to 2500 ft. After discussing that for 30 seconds or so, we figured out that due to a drastic pressure change from the day before that we set the altimeter 1000 ft low. Thus, making us actually at 3500 ft. We descended out of class B as quickly as possible. More thoroughness on my part would have prevented the problem.

Original NASA ASRS Text

Title: SMA TRAINEE AND INSTRUCTOR PENETRATED STL CLASS B AIRSPACE.

Narrative: WE WERE CLBING OUT OF CPS NBOUND. WE LEVELED OFF AT 2500 FT. CLASS B STARTED AT 3000 FT. I NOTED TO MY INSTRUCTOR THAT IT TOOK US AN AWFULLY LONG TIME TO CLB TO 2500 FT. AFTER DISCUSSING THAT FOR 30 SECONDS OR SO, WE FIGURED OUT THAT DUE TO A DRASTIC PRESSURE CHANGE FROM THE DAY BEFORE THAT WE SET THE ALTIMETER 1000 FT LOW. THUS, MAKING US ACTUALLY AT 3500 FT. WE DSNDED OUT OF CLASS B AS QUICKLY AS POSSIBLE. MORE THOROUGHNESS ON MY PART WOULD HAVE PREVENTED THE PROB.

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.