Altitude deviation occurs when EMB120 crew fails to properly monitor altitude after an altimeter setting change near pdz, ca.

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Attributes
ACN	512100
Time
Date	200105
Day	Thu
Local Time Of Day	1801 To 2400
Place
Locale Reference	navaid : pdz.vortac
State Reference	CA
Altitude	msl bound lower : 12000 msl bound upper : 12500
Environment
Flight Conditions	VMC
Light	Dusk
Aircraft 1
Controlling Facilities	tower : msp.tower
Operator	common carrier : air carrier
Make Model Name	Brasilia EMB-120 All Series
Flight Phase	climbout : intermediate altitude cruise : level
Flight Plan	IFR
Person 1
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 7100 flight time type : 2300
ASRS Report	512100
Events
Anomaly	altitude deviation : overshoot altitude deviation : excursion from assigned altitude inflight encounter : turbulence non adherence : published procedure non adherence : clearance other anomaly other
Resolutory Action	controller : issued advisory flight crew : returned to assigned altitude
Supplementary
Problem Areas	Flight Crew Human Performance Environmental Factor Aircraft Weather
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We had departed palm springs and were climbing to 12000 ft MSL. The wind in psp was strong and gusty and we were experiencing turbulence. Leveling at 12000 ft we were provided a new altimeter setting from socal approach 29.98. This was quite a large difference from the previous psp setting of 29.74. The new setting caused our indicated altitude to be approximately 200 ft high of assigned altitude (12000 ft). I observed the first officer begin a descent back to 12000 ft. I then started to calculate cruise engine torque data using performance charts. When I looked back at altimeter I realized (simultaneously with first officer) that we had climbed to 12500 ft. An ATC inquiry as to our altitude deviation occurred shortly thereafter and we corrected altitude. Contributing factors: -- #1) I believe the altimeter change affected the altitude capture mode of the flight director and autoplt in a way we should have anticipated, but didn't. #2) its possible that due to the winds in the pass at the time, we encountered an up-draft that was beyond the normal corrective range of the flight director autoplt. Summary -- we should have been paying more attention to the aircraft.

Original NASA ASRS Text

Title: ALT DEV OCCURS WHEN EMB120 CREW FAILS TO PROPERLY MONITOR ALT AFTER AN ALTIMETER SETTING CHANGE NEAR PDZ, CA.

Narrative: WE HAD DEPARTED PALM SPRINGS AND WERE CLBING TO 12000 FT MSL. THE WIND IN PSP WAS STRONG AND GUSTY AND WE WERE EXPERIENCING TURBULENCE. LEVELING AT 12000 FT WE WERE PROVIDED A NEW ALTIMETER SETTING FROM SOCAL APCH 29.98. THIS WAS QUITE A LARGE DIFFERENCE FROM THE PREVIOUS PSP SETTING OF 29.74. THE NEW SETTING CAUSED OUR INDICATED ALT TO BE APPROX 200 FT HIGH OF ASSIGNED ALT (12000 FT). I OBSERVED THE FO BEGIN A DSCNT BACK TO 12000 FT. I THEN STARTED TO CALCULATE CRUISE ENGINE TORQUE DATA USING PERFORMANCE CHARTS. WHEN I LOOKED BACK AT ALTIMETER I REALIZED (SIMULTANEOUSLY WITH FO) THAT WE HAD CLBED TO 12500 FT. AN ATC INQUIRY AS TO OUR ALT DEV OCCURRED SHORTLY THEREAFTER AND WE CORRECTED ALT. CONTRIBUTING FACTORS: -- #1) I BELIEVE THE ALTIMETER CHANGE AFFECTED THE ALTITUDE CAPTURE MODE OF THE FLT DIRECTOR AND AUTOPLT IN A WAY WE SHOULD HAVE ANTICIPATED, BUT DIDN'T. #2) ITS POSSIBLE THAT DUE TO THE WINDS IN THE PASS AT THE TIME, WE ENCOUNTERED AN UP-DRAFT THAT WAS BEYOND THE NORMAL CORRECTIVE RANGE OF THE FLT DIRECTOR AUTOPLT. SUMMARY -- WE SHOULD HAVE BEEN PAYING MORE ATTN TO THE ACFT.

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.