GA SMA ENCOUNTERED ICING DURING DESCENT THAT LIMITED CLIMB CAPABILITY.

Narrative

I WAS ON A FLT ORIGINATING IN ROCKFORD; IL TO JOHNSON COUNTY INDUSTRIAL ARPT (IXD) IN OLATHE; KS. AN HOUR INTO FLT MY RIGHT ALTERNATOR FAILED. AFTER SECURING THE SYS; I CONTACTED FLT SVC FOR AN UPDATED WX BRIEFING AT MY DEST AND DECIDED TO CONTINUE THE FLT AND ADVISED CHICAGO CENTER. LATER THE KS CITY CTLR ADVISED ME OF THE ROUTE CHANGE DIRECT TO LASSO INTXN; LASSO TWO ARR; AND TO DSND PLT'S DISCRETION TO 6000'. I ACKNOWLEDGED TO THE CTLR I WOULD PREFER TO STAY AT 8000' AND ABOVE THE TOPS DUE TO ONE ALTERNATOR INOP; AS THE LAST PLT RPT IN THE AREA WERE TOPS AT 6300'. SHORTLY AFTER REACHING LASSO INTXN AND TURNED OVER TO KS CITY APCH CTL; I WAS IN THE CLOUDS AT 8500' AND PICKING UP MODERATE RIME. DECIDING TO ASK FOR LOWER ALT; WE WERE CLRED TO 6000 AND THEN 4000'. DURING THIS DSCNT PERIOD OF TIME; APPROX 6 TO 8 MINS; I ENTERED MODERATE AND SEVERE MIXED RIME AND CLR ICE AND FREEZING RAIN. THERE WERE TIMES WHERE I HAD TO CYCLE MY BOOTS EVERY 30 SECONDS; AS I WAS HAVING IN EXCESS OF 1/2' OF BUILD UP ON THE WING BOOTS. MY WINDSHIELD WAS ICED UP HEAVILY AND AS I WENT THROUGH A SMALL LAYER (300') OF RAIN THERE WAS SOME RELIEF FROM THE ICING. HOWEVER; THE PRECIP CHANGED BACK TO ICE AND THE BUILD UP BECAME SEVERE AGAIN ALL OVER THE AIRPLANE. THE ICE BUILD UP ON MY L ENG INNER COOLER SCOOP ON THE NACELLE HAD TWO LAYERS OF ICE TOTALING IN EXCESS OF 2' AND CLR ICE WAS ROLLED BACK OVER THE WING TO THE BEGINNING OF THE FRONT SPAR AND THE SIDE WINDOWS WERE ICED UP WHERE I HAD TO PULL MY HEAD BACK AND TURN TO SEE THE WING AND THE ENG NACELLE. I WAS 30 TO 40 MI FROM THE ARPT AND REQUESTED A CLB BACK ON TOP OR TO FIND A LAYER WHERE ICING WAS NOT SO SEVERE. I CONFIGURE THE AIRPLANE FOR A CLB AT 140 KTS; CLB PWR OF 36' AND 2400 RPM; AND MAINTAINED THE 140 KTS SPD THROUGH CONTINUOUS MODERATE TO SEVERE ICING CONDITIONS. AT 8500' THERE WAS NO CLB LEFT AVAILABLE AND THE AIRPLANE WAS IN CONTINUOUS AERODYNAMIC BUFFET; AS WHAT IS PROCEEDED BEFORE A STALL. I DECLARED AN EMER WITH APCH CTL; WHICH THEY ACKNOWLEDGED AND I STARTED AN IMMED DSCNT AND ASKED FOR VECTORS FOR THE ILS35 AT MY DEST. APCH CTL WAS VERY EXPEDITIOUS AND OBVIOUSLY A TREMENDOUS ASSIST; WHICH HELPED MY CONFIDENCE LEVEL TREMENDOUSLY. MY XMISSIONS WERE BREAKING UP AND MY NAV RECEIVERS WERE ALSO HAVING OCCASIONAL GLITCHES WITH THE NAV FLAG COMING ON AND OFF. I WAS ABLE TO HEAR APCH CTL CLRING AND ADVISED THEM OF THE POSSIBILITY OF HAVING TO GIVE ME A NO GYRO APCH. DSCNT WAS AT 1000' PER MINUTE AT 160 TO 170 KTS WITH THE ICING CONDITIONS CONTINUING. ALL THIS TIME REQUIRING FULL ELECTRICAL DE-ICE HEAT; (RIGHT ALTERNATOR INOP) AND USE OF THE BOOTS EVERY COUPLE MINUTES FOR 1/4' TO 1/2' OF ICE ON THE WING. DURING DSCNT SOME OF THE ICE DID DISSIPATE FROM SOME OF THE APPENDAGES OF THE AIRPLANE. AFTER INTERCEPTING THE LOC AND BELOW G/S IT REQUIRED FULL PWR AND FULL RPM TO COAX THE AIRPLANE BACK UP THE G/S. I BROKE OUT AT APPROX 700 TO 800' AGL AND HAD THE ARPT IN SIGHT APPROX 2 1/2 TO 3 MI. I LEFT THE GEAR UP UNTIL OVER THE RABBIT AND DID NOT DUMP THE FLAPS UNTIL I WAS OVER THE RWY AT A LOW ALT OF 20'; AS I WAS STILL AT 140 KTS INDICATED AND LANDED W/O INCIDENT.