1) THE PILOTS DECISION TO ATTEMPT VFR FLIGHT INTO INSTRUMENT METEOROLOGICAL CONDITIONS, WHICH INCLUDED MOUNTAIN OBSCUREMENT AND SEVERE MIXED ICING, AND, 2) HIS FAILURE TO MAINTAIN CONTROL OF THE AIRCRAFT DUE TO A PROBABLE AERODYNAMIC STALL INDUCED BY SEVERE AIRFRAME ICING. FACTORS IN THE ACCIDENT WERE: 1) THE FORECAST WEATHER CONDITIONS OF ICING, LOW CLOUD CEILINGS AND MOUNTAIN OBSCURATION, AND 2) THE PILOTS FAILURE TO OBTAIN EITHER PREFLIGHT OR INFLIGHT WEATHER INFORMATION FOR HIS ROUTE OF FLIGHT.