While climbing toward 5000 ft, autoplt fails to keep aircraft climbing and it descends to 3000 ft.

Attributes
ACN	261514
Time
Date	199401
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : djb airport : cle
State Reference	OH
Altitude	msl bound lower : 3000 msl bound upper : 5000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : cle
Operator	common carrier : air carrier
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 121
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 250 flight time total : 9200 flight time type : 3500
ASRS Report	261514
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude
Independent Detector	other controllera other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

We were climbing to assigned altitude of 5000 ft with the autoplt operating. I got distracted with checking a chart as did the first officer. He suddenly said, 'what's going on here?' and I looked and saw that we were in a descent passing through 3000 ft. I immediately disengaged the autoplt and reinitiated a climb. Departure control asked what our altitude was and we reported it, as well as an autoplt malfunction. I asked if there was a problem and he said no. We retried the autoplt and had no further problems with it. I should not have allowed myself to become distracted during the climb out below 10000 ft, and should monitor the progress more alertly without total reliance upon the autoplt.

Original NASA ASRS Text

Title: WHILE CLBING TOWARD 5000 FT, AUTOPLT FAILS TO KEEP ACFT CLBING AND IT DSNDS TO 3000 FT.

Narrative: WE WERE CLBING TO ASSIGNED ALT OF 5000 FT WITH THE AUTOPLT OPERATING. I GOT DISTRACTED WITH CHKING A CHART AS DID THE FO. HE SUDDENLY SAID, 'WHAT'S GOING ON HERE?' AND I LOOKED AND SAW THAT WE WERE IN A DSCNT PASSING THROUGH 3000 FT. I IMMEDIATELY DISENGAGED THE AUTOPLT AND REINITIATED A CLB. DEP CTL ASKED WHAT OUR ALT WAS AND WE RPTED IT, AS WELL AS AN AUTOPLT MALFUNCTION. I ASKED IF THERE WAS A PROB AND HE SAID NO. WE RETRIED THE AUTOPLT AND HAD NO FURTHER PROBS WITH IT. I SHOULD NOT HAVE ALLOWED MYSELF TO BECOME DISTRACTED DURING THE CLBOUT BELOW 10000 FT, AND SHOULD MONITOR THE PROGRESS MORE ALERTLY WITHOUT TOTAL RELIANCE UPON THE AUTOPLT.

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.