PILOT'S FAILURE TO TAKE ACTION THAT WOULD PREVENT THE FORMATION OF CARBURETOR ICE. FOLLOWING THE ENGINE MALFUNCTION, THE PILOT DID NOT CONFIGURE THE AIRPLANE SO AS TO REDUCE THE SEVERITY OF THE IMPACT, I.E. EXTEND THE FLAPS AND SLOW THE AIRPLANE. CONTRIBUTING TO THE ACCIDENT WAS THE LACK OF A REQUIREMENT BY THE FAA FOR THE AUTOGAS STC HOLDER TO PUBLISH CARBURETOR ICING PROBABILITY IMFORMATION.