Six people, including a child, died Tuesday night when a Piper PA-46 Malibu flying from Kenosha to Menomonie crashed in a wooded part of Sauk County near Mirror Lake State Park.
The National Transportation Safety Board said the pilot, flying at 24,000 feet, told controllers ice was building on the wings and asked to descend. Controllers approved the request.
Investigators said the plane then entered a descending right turn that grew sharper, before contact and tracking were lost. Flight data cited by investigators showed speed rising and a descent rate reaching about 4,000 feet per minute.
Rain and a thunderstorm were moving through the Dellona area at the time. The plane came down shortly before 10 p.m., about 10 miles west of Wisconsin Dells.
No buildings were damaged and no one on the ground was hurt. Names of those aboard had not been released publicly.
The NTSB is leading the investigation and has not named an official cause. The Malibu model was the subject of a federal safety review decades ago after a series of icing-related crashes, which led to recommendations on training, checklists and ice-protection indicators.
