What happened
Prior to departing Knoxville (TYS) for Nashville (BNA), a Flight Service Station specialist briefed the pilot on a cold front west of BNA, noting reported icing at 2,000 feet and 4,000 feet. The pilot was also informed of Airmet Zulu 3, which forecasted only light to moderate rime or mixed icing between 8,000 and 20,000 feet along the route.
During the flight, the pilot entered instrument meteorological conditions (IMC) and activated the pitot heat. While descending from 6,000 feet to 4,000 feet, the pilot encountered icing conditions and attempted to climb back to 5,000 feet. The aircraft was unable to maintain altitude and began to descend. The pilot reported that the pitot system iced over, causing the airspeed indicator to drop to zero, prompting him to declare an emergency.
The pilot diverted to Smithville to utilize a published NDB approach. Although the NDB was not operational, the ARTCC controller provided a frequency for it. As the aircraft descended to approximately 2,000 feet MSL, it broke through the cloud layer. The pilot requested a frequency to activate the runway lights and, after a two-minute delay, received the information.
Upon extending the landing gear and reducing power for final approach, the pilot noted a slight buffet. Ice accumulation on the windscreen restricted forward visibility. In an attempt to visually check runway alignment, the pilot applied rudder to yaw the aircraft. During this maneuver, the airplane struck rising terrain approximately 239 feet short of the runway. Post-accident inspection confirmed that the pitot heat was operational.