Accident Summary
An instrument-rated commercial pilot, the sole occupant with 1,027 hours of flight experience, was conducting a cross-country flight under instrument flight rules (IFR). The pilot had limited his weather briefing, filed an IFR flight plan, and received an ATC clearance. Approximately 13 minutes after departure, the pilot reported that the airplane was accumulating ice. He requested and was cleared to descend from 5,000 to 4,000 feet mean sea level (msl). Subsequently, the pilot requested and was cleared to descend to 3,000 feet and proceed direct to the initial approach fix for the RNAV (GPS) Runway 36 non-precision approach at an alternate airport. No distress call or further ATC communications were recorded. The airplane struck trees and terrain about 17 nautical miles south of the airport. The impact characteristics—tree deformation, ground scars, and craters—were consistent with a near-vertical impact.
Weather Conditions
Instrument meteorological conditions prevailed at the departure airport and along the flight route, with low ceilings, reduced visibility, light rain, mist, and drizzle. A National Transportation Safety Board meteorological study indicated that the low-level vertical temperature profile in the accident area was likely: 1°C at the surface, -3°C at 3,000 feet, a freezing level at 5,000 feet, and above-freezing temperatures at 7,000–8,000 feet. Supercooled large droplets (SLD) were likely present at and below 5,000 feet, producing moderate to severe clear icing on the airframe in the minutes before the accident.
Post-Impact Findings
The airplane was equipped with alcohol propellers; however, impact and thermal destruction precluded determination of the anti-ice system's operational status. Both propellers exhibited blade bending and twisting consistent with high power (at or near the low pitch range) and rotation (symmetrical energy) at impact. No evidence of an in-flight mechanical or flight control malfunction was found that would have rendered the airplane uncontrollable prior to impact. The GPS unit was not approved for IFR operations. After the accident, the FAA flight-checked the RNAV (GPS) Runway 36 approach, and all components were found to be operating within prescribed tolerances.