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.