Narrative:

Climb from FL280 to FL310, the autoplt failed to capture FL310. The altitude alert sounded at FL312.5. The ascent was reversed and FL310 was captured. Why the autoplt failed to capture FL310 is unknown. Contributing factors to this altitude excursion were thunderstorm deviations and the activation of anti-ice system which diverted our attention.

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Original NASA ASRS Text

Title: AN MD80 FLT CREW OVERSHOT ASSIGNED ALT WHILE BEING DISTR BY WX.

Narrative: CLB FROM FL280 TO FL310, THE AUTOPLT FAILED TO CAPTURE FL310. THE ALT ALERT SOUNDED AT FL312.5. THE ASCENT WAS REVERSED AND FL310 WAS CAPTURED. WHY THE AUTOPLT FAILED TO CAPTURE FL310 IS UNKNOWN. CONTRIBUTING FACTORS TO THIS ALT EXCURSION WERE TSTM DEVS AND THE ACTIVATION OF ANTI-ICE SYS WHICH DIVERTED OUR ATTN.

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.