Narrative:

I was at 9000' and told to descend and maintain 5000'. I was getting ready to begin my approach to hfd, so I set the altitude preselect and began my descent. At this point I switched over to listen to the ATIS for hfd. While copying the ATIS I hit a few bumps which disengaged the autoplt. Since I was busy with getting ready for the approach, I did not notice the autoplt disengage. The altitude preselect did not capture 5000'. I noticed when approximately at 4500' and immediately went back to 5000'. I could not have been below 5000' for more than 2 mins. Comment: autoplts are great, but don't stop scanning all INS just because it is clear out and no traffic in area.

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Original NASA ASRS Text

Title: PLT OF SMA ON IFR PLAN CLEARED TO 5000' INADVERTENTLY DISENGAGED HIS AUTOPLT AND ACFT DESCENDED TO 4500' BEFORE RECOVERY TO 5000'.

Narrative: I WAS AT 9000' AND TOLD TO DSND AND MAINTAIN 5000'. I WAS GETTING READY TO BEGIN MY APCH TO HFD, SO I SET THE ALT PRESELECT AND BEGAN MY DSNT. AT THIS POINT I SWITCHED OVER TO LISTEN TO THE ATIS FOR HFD. WHILE COPYING THE ATIS I HIT A FEW BUMPS WHICH DISENGAGED THE AUTOPLT. SINCE I WAS BUSY WITH GETTING READY FOR THE APCH, I DID NOT NOTICE THE AUTOPLT DISENGAGE. THE ALT PRESELECT DID NOT CAPTURE 5000'. I NOTICED WHEN APPROX AT 4500' AND IMMEDIATELY WENT BACK TO 5000'. I COULD NOT HAVE BEEN BELOW 5000' FOR MORE THAN 2 MINS. COMMENT: AUTOPLTS ARE GREAT, BUT DON'T STOP SCANNING ALL INS JUST BECAUSE IT IS CLR OUT AND NO TFC IN AREA.

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.