Narrative:

After being cleared out of 25000', descent was initiated on autoplt. Aircraft immediately pitched up. Because of light weight and speed, aircraft climbed at 2000 FPM. Autoplt was disengaged after 450' of climb at 2000-2500 FPM. Descent was initiated after approximately 900' of climb. I believe low time in aircraft contributed to my response time. Because of VMC conditions and good visibility abrupt control inputs.

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Original NASA ASRS Text

Title: WHEN WDB ACFT WAS TAKEN OFF THE AUTOPLT TO START A DESCENT, ACFT PITCHED UP ABRUPTLY AND CLIMBED UNTIL FO FLYING WAS ABLE TO RECOVER THE ACFT AND START DESCENT.

Narrative: AFTER BEING CLRED OUT OF 25000', DSNT WAS INITIATED ON AUTOPLT. ACFT IMMEDIATELY PITCHED UP. BECAUSE OF LIGHT WT AND SPD, ACFT CLBED AT 2000 FPM. AUTOPLT WAS DISENGAGED AFTER 450' OF CLB AT 2000-2500 FPM. DSNT WAS INITIATED AFTER APPROX 900' OF CLB. I BELIEVE LOW TIME IN ACFT CONTRIBUTED TO MY RESPONSE TIME. BECAUSE OF VMC CONDITIONS AND GOOD VISIBILITY ABRUPT CTL INPUTS.

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.