DEBONAIR PLT OVERSHOOTS HIS ALT IN DSCNT WHILE IMC INTO VMC CONDITIONS; A NEAR CFTT; 18 MI SE OF PKD; MN.

Narrative

ON SEP/FRI/03; I WAS FLYING A DEBONAIR IFR FROM GGI TO PKD. CRUISING AT 8000 FT THERE WAS A SOLID CLOUD LAYER IN THE AREA OF PKD WITH TOPS RPTED AT 6500 FT. THE PKD ASOS RPTED CEILING AT 3300 FT WHICH WOULD PUT THE BOTTOM OF THE LAYER AT 4700 FT MSL. I WAS CLRED DOWN TO 5000 FT BY ZMA; WHICH PUT ME IN THE CLOUDS. ABOUT 20 MI OUT I WAS CLRED TO 3500 FT. I PUNCHED OFF ALT HOLD; BEGAN THE DSCNT AND SET UP THE APCH ON THE GPS. KNOWING I WOULD BREAK OUT BEFORE REACHING 3500 FT I MONITORED DSCNT RATE WHILE ORGANIZING THE COCKPIT AND PANEL. ATC ASKED IF I COULD DO A VISUAL APCH INTO PKD AND I RESPONDED; BASED ON THE ASOS CEILING RPT; THAT YES; I SHOULD BE ABLE TO DO THE VISUAL. JUST AS I BROKE OUT OF THE CLOUDS; AND ATC CALLED AND SAID RADAR CONTACT WAS LOST. IT WAS THEN I GLANCED AT THE ALTIMETER AND DISCOVERED I WAS AT 3000 FT 500 FT BELOW THE ASSIGNED ALT. (THE CEILING WAS ACTUALLY 2000 FT AGL OR ABOUT 3400 FT MSL.) I APOLOGIZED THAT I HAD GONE SO LOW. ATC TOLD ME TO CLB BACK TO 3500 FT AND RPT ESTABLISHED ON AN APCH TO PKD. HOWEVER; I HAD THE ARPT IN SIGHT AND KNEW THERE WAS ANOTHER ACFT BEHIND ME ENRTE TO PKD. RATHER THAN CLB BACK INTO IMC AND MANEUVER TO GET ON AN APCH; I CANCELED IFR AND PROCEEDED STRAIGHT IN TO RWY 31 AT PKD. LESSONS LEARNED -- MONITOR ALTIMETER CLOSER -- DON'T GET DISTR BY COCKPIT CHORES; ASOS MAY BE ACCURATE BUT ONLY ABOVE THE ARPT. I CHOSE TO CANCEL AND GO STRAIGHT TO ARPT TO AVOID DELAYS OR CONFLICTS WITH OTHER ACFT WHICH WOULD HAVE MADE THIS MISTAKE WORSE.