Investigators zero in on possible cause of Wisconsin plane crash that killed 6

A small plane that crashed in Wisconsin, killing six people, including a child, had plummeted toward the ground at a rate of up to 4,000 feet per minute after its pilot reported ice accumulating on the wings, according to newly released flight data and federal investigators.

The National Transportation Safety Board (NTSB) said the pilot of the Piper PA-46 Malibu was flying at 24,000 feet on Tuesday night when he alerted air traffic control to ice building up on the aircraft's wings and requested permission to descend.