Narrative:

Upon descending from FL350 to FL240 the first officer turned off the autothrottles. Autoplt tried to level off but it appeared that it was going to go below FL240. Autoplt was turned off, and aircraft was hand flown to leveloff. I believe this was due to turning off autothrottle during leveloff. The autoplt could not level smoothly or at assigned altitude without autothrottle on.

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Original NASA ASRS Text

Title: MD80 SUPER 80 DSNDED 300 FT BELOW ASSIGNED ALT WHEN AUTOPLT FAILED TO CAPTURE ALT. AUTOTHROTTLES WERE INOP.

Narrative: UPON DSNDING FROM FL350 TO FL240 THE FO TURNED OFF THE AUTOTHROTTLES. AUTOPLT TRIED TO LEVEL OFF BUT IT APPEARED THAT IT WAS GOING TO GO BELOW FL240. AUTOPLT WAS TURNED OFF, AND ACFT WAS HAND FLOWN TO LEVELOFF. I BELIEVE THIS WAS DUE TO TURNING OFF AUTOTHROTTLE DURING LEVELOFF. THE AUTOPLT COULD NOT LEVEL SMOOTHLY OR AT ASSIGNED ALT WITHOUT AUTOTHROTTLE ON.

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.