DURING ARRIVAL, A DESCENT WAS BEGUN FROM 8000 TO 7000 FT MSL AT 0151 HST. AT 0155 HST, THE AIRCREW WAS CLEARED FOR A VISUAL APCH FROM 7000 FT MSL & A RAPID DESCENT WAS STARTED WITH 20 DEG OF FLAPS & APRX 25 INCHES MAP (MANIFOLD PRESSURE). THE ACFT WAS MANEUVERED TO INTERCEPT THE ILS LOCALIZER & GLIDE SLOPE AS A REFERENCE. AFTER INTERCEPTING THE GLIDE SLOPE AT ABOUT 3000 FT, THE PILOT-IN-COMMAND (PIC) CALLED FOR 2250 RPM & GEAR EXTENSION. WHILE DESCENDING THRU APRX 2000 FT, HE NOTICED THE ACFT SLOWING DOWN & DESCENDING BELOW THE GLIDE SLOPE, SO HE CALLED FOR A POWER INCREASE TO 27 INCHES MAP. AT ABOUT THAT TIME, THE AIRCREW NOTED THAT THE ENGS WERE NOT RESPONDING & HAD LOST POWER. SUBSEQUENTLY, A FORCED LANDING WAS MADE IN A SUGAR CANE FIELD WITH THE GEAR IN A TRANSIENT POSITION. THE FUEL SELECTORS WERE FOUND POSITIONED TO FUEL TANKS CONTAINING FUEL, BUT THE POSITIONING DURING THE DESCENT WAS NOT VERIFIED. THE TEMP &DEW POINT WERE 72 & 65 DEG. THIS WOULD HAVE BEEN BARELY WITHIN THE ENVELOPE FOR CARB ICE ON ICING PROBABILITY CHARTS.