Pre-Flight Briefing
Before departing Knoxville (TYS) for Nashville (BNA), a flight service station specialist at BNA briefed the pilot on a cold front west of Nashville and icing reported at 2,000 and 4,000 feet west of the front. The pilot was also briefed on information from Airmet Zulu 3, which forecast only light occasional moderate rime or mixed icing along the route between 8,000 and 20,000 feet.
En Route Icing Encounter
The pilot entered instrument meteorological conditions (IMC) en route and activated the pitot heat. After a descent from 6,000 to 4,000 feet, the pilot noted icing conditions and requested a climb to 5,000 feet. However, he was unable to maintain altitude, and the airplane began descending. The pilot reported that the pitot system had iced over, causing the airspeed indicator to drop to zero, and he declared an emergency.
Diversion to Smithville
The pilot diverted to Smithville, which had a published NDB approach. The NDB was not operating, but the ARTCC controller provided a frequency for the NDB. At about 2,000 feet mean sea level, the airplane descended below the clouds, and the pilot requested a frequency to activate the runway lights. After a delay of approximately two minutes, the frequency was provided. The pilot activated the runway lights, maneuvered onto final approach, and extended the landing gear. As power was reduced, he noted a slight buffet.
Approach and Collision with Terrain
Ice on the windscreen limited forward visibility. While attempting to reach the runway, the pilot applied rudder to yaw the airplane and visually check runway alignment. At about that time, the airplane struck rising terrain 239 feet short of the runway. The pitot heat was found to be operational after the accident.