Narrative:

I was on a layover and awoke in the morning with less than a good night's sleep. I called my wife at home and proceeded to get into a disagreement with her. By the time I checked in for my trip I felt ok, but was still a little bothered by the disagreement with my wife. The copilot, who was new on the equipment, was flying as we climbed out of atlanta, on our way to akron/canton, oh. We were supposed to level off at FL310, and because the copilot had been doing a great job for the last few days, I lowered my guard and wasn't paying attention to what was going on. When he tried to level off at FL310 the autoplt malfunctioned and kept climbing. I didn't notice until the altitude warning went off. I immediately pushed forward on the yoke to stop the climb but by now we were over 250 ft high. ATC asked about our altitude and I told him we were high because of an autoplt malfunction and were correcting. We eventually had to disengage the autoplt because it wouldn't level off. Contributing factors were a new copilot, a bad autoplt, lack of a good night's sleep, and preoccupation with problems at home. The solution: when flying, leave your problems at home, and regardless of whose hands are on the controls, always pay attention to what is going on. Supplemental information from acn 436146: later in the flight we had trouble with the autoplt maintaining altitude. We flew the rest of the trip with the autoplt disengaged. Although maintenance later worked on the autoplt, I don't know what their findings were. I feel that a lack of experience with the autoplt contributed to the occurrence but that autoplt malfunction was the primary reason.

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Original NASA ASRS Text

Title: A CLBING DC9-30 OVERSHOOTS ITS ASSIGNED ALT BY ABOUT 250 FT.

Narrative: I WAS ON A LAYOVER AND AWOKE IN THE MORNING WITH LESS THAN A GOOD NIGHT'S SLEEP. I CALLED MY WIFE AT HOME AND PROCEEDED TO GET INTO A DISAGREEMENT WITH HER. BY THE TIME I CHKED IN FOR MY TRIP I FELT OK, BUT WAS STILL A LITTLE BOTHERED BY THE DISAGREEMENT WITH MY WIFE. THE COPLT, WHO WAS NEW ON THE EQUIP, WAS FLYING AS WE CLBED OUT OF ATLANTA, ON OUR WAY TO AKRON/CANTON, OH. WE WERE SUPPOSED TO LEVEL OFF AT FL310, AND BECAUSE THE COPLT HAD BEEN DOING A GREAT JOB FOR THE LAST FEW DAYS, I LOWERED MY GUARD AND WASN'T PAYING ATTN TO WHAT WAS GOING ON. WHEN HE TRIED TO LEVEL OFF AT FL310 THE AUTOPLT MALFUNCTIONED AND KEPT CLBING. I DIDN'T NOTICE UNTIL THE ALT WARNING WENT OFF. I IMMEDIATELY PUSHED FORWARD ON THE YOKE TO STOP THE CLB BUT BY NOW WE WERE OVER 250 FT HIGH. ATC ASKED ABOUT OUR ALT AND I TOLD HIM WE WERE HIGH BECAUSE OF AN AUTOPLT MALFUNCTION AND WERE CORRECTING. WE EVENTUALLY HAD TO DISENGAGE THE AUTOPLT BECAUSE IT WOULDN'T LEVEL OFF. CONTRIBUTING FACTORS WERE A NEW COPLT, A BAD AUTOPLT, LACK OF A GOOD NIGHT'S SLEEP, AND PREOCCUPATION WITH PROBS AT HOME. THE SOLUTION: WHEN FLYING, LEAVE YOUR PROBS AT HOME, AND REGARDLESS OF WHOSE HANDS ARE ON THE CTLS, ALWAYS PAY ATTN TO WHAT IS GOING ON. SUPPLEMENTAL INFO FROM ACN 436146: LATER IN THE FLT WE HAD TROUBLE WITH THE AUTOPLT MAINTAINING ALT. WE FLEW THE REST OF THE TRIP WITH THE AUTOPLT DISENGAGED. ALTHOUGH MAINT LATER WORKED ON THE AUTOPLT, I DON'T KNOW WHAT THEIR FINDINGS WERE. I FEEL THAT A LACK OF EXPERIENCE WITH THE AUTOPLT CONTRIBUTED TO THE OCCURRENCE BUT THAT AUTOPLT MALFUNCTION WAS THE PRIMARY REASON.

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.