Wisconsin Plane Crash: Icing Data Reveals Fatal 4,000 FPM Dive

A single-engine Piper PA-46 Malibu carrying six people, including a child, entered an unrecoverable dive after ice accumulated on its wings at 24,000 feet over Wisconsin, according to preliminary flight data released by the National Transportation Safety Board.

The aircraft plummeted at up to 4,000 feet per minute late Tuesday night, with radar tracking showing airspeed nearly doubling to 340 mph before all communications and telemetry were lost. The plane crashed in a wooded area of Dellona in Sauk County, roughly 10 miles west of Wisconsin Dells near Mirror Lake State Park, shortly before 10 p.m. All six occupants died. No structures were struck and no one on the ground was injured. A thunderstorm was moving through the area, bringing rain at the time of impact.

Flight data indicates the pilot contacted air traffic control to report icing on the wings and requested an immediate descent. Controllers approved the request, but the aircraft subsequently entered a descending right turn that tightened progressively until radar contact ceased.

“It has all the earmarks of an icing-related loss of control,” aviation safety expert Jeff Guzzetti, a former investigator for both the NTSB and the Federal Aviation Administration, told The Associated Press.

Atmospheric icing remains one of the most lethal hazards in general aviation. When supercooled water droplets freeze on an aircraft’s leading edges, they alter the aerodynamic profile of the wing. This disruption destroys smooth airflow, drastically reducing lift while simultaneously increasing drag. In severe cases, ice accumulation can render standard control surfaces ineffective within minutes. Aircraft certified for flight into known icing conditions carry pneumatic de-icing boots or heated leading edges, but these systems have operational limits and cannot always shed heavy or rapid accumulations, particularly in convective weather such as thunderstorms.

The Piper PA-46 Malibu is a high-performance, pressurized, six-seat aircraft widely used by owner-pilots and charter operators for cross-country travel. Its ability to cruise at high altitudes makes it popular for regional flights, but operating in the mid-to-upper flight levels exposes the airframe to severe icing environments that require specialized training to manage safely. The model has drawn federal scrutiny previously over its vulnerability to winter weather. Between 1989 and 1991, the NTSB conducted a special safety review examining seven icing-related crashes involving Piper Malibu and Mirage variants. That investigation found that several accidents involved pilots who lacked sufficient experience handling the complex, high-altitude aircraft in freezing conditions. The resulting safety recommendations prompted changes to pilot training requirements, revised operating manuals, updated checklists, and the mandated addition of indicator lights for pitot tube heating systems, which are critical for maintaining accurate airspeed readings when ice is present.

The doomed flight originated in Kenosha, Wisconsin, and was bound for Menomonie, a route spanning roughly 250 miles across the state. Authorities have not yet publicly released the identities of the victims.

The crash occurred during a week of heightened scrutiny on U.S. aviation safety. Separately, the Coast Guard recently suspended a search for a Boston-bound medevac aircraft carrying six people that disappeared off the coast of Nantucket. Another fatal air ambulance crash earlier this year exposed growing vulnerabilities related to GPS signal interference affecting domestic flights.

NTSB investigators are currently analyzing the aircraft’s final transmissions with air traffic control. An official cause of the crash has not been determined.