Accident Sequence
The airplane was established at a cruise altitude of 12,000 feet with no reported issues during the en route portion. Upon initial clearance to descend, the pilot advised the controller of potential ice, leading to a clearance to 7,000 feet instead of the initial 4,000 feet. About 15 miles from the destination airport, the pilot was cleared for a GPS approach and instructed to maintain 3,900 feet until the initial approach fix. The pilot later requested and received clearance to 3,600 feet, commenting that the airplane was "picking up some ice."
Track data showed the airplane descended to as low as 3,200 feet. Approximately 2.25 miles from the airport, the pilot declared a missed approach, citing too much ice. The flight was cleared to an alternate airport and instructed to climb to 5,000 feet, but the airplane could not climb above 4,500 feet. The pilot reported continued ice accumulation and was unable to maintain altitude, noting "more ice" and losing altitude "pretty good." The pilot requested vectors out of the icing conditions, but the controller was unaware of any better area.
The pilot selected an intermediate airport closer to the present position. The controller cleared the flight and instructed to maintain 4,000 feet; the pilot replied, "All I can do is 4,000." Track data indicated the airplane established an east-southeasterly course, passed about 0.6 miles south of the intermediate airport, then entered a left turn to a northeast course, passing the airport apparently intending to return. The airplane impacted trees and terrain about 1.75 miles northeast of the intermediate airport. A witness reported the airplane came through the treetops, "nose dived into the ground," and spun around before coming to rest.
GPS altitude data revealed a steadily increasing descent rate after reaching 4,500 feet during the diversion.
Weather Conditions
AIRMET advisories for moderate icing were in effect for the destination and alternate airports. The pilot obtained two pre-flight weather briefings where the AIRMET was advised. Although the AIRMET was updated after the briefings, the predicted icing intensity and geographical coverage area remained the same.
Aircraft Information
A post-accident inspection of the airplane revealed no anomalies consistent with a pre-impact failure or malfunction. Several ice fragments, consistent in appearance to rime ice, were observed on the ground at the accident site by initial responders. The fragments exhibited a contour approximately matching the profile of the wing leading edge. The Pilot's Operating Handbook stated that the airplane was not certified for flight into known icing conditions and advised that in the case of an inadvertent icing encounter, "evasive action should be initiated immediately when icing conditions are first encountered."