Incident Details
The incident occurred during an instrument landing system (ILS) approach at Central Wisconsin Airport. The crew had executed a missed approach on the first attempt and decided to perform the complete procedure turn for the ILS. Both the first and second approaches were flown at an altitude of 3,000 feet mean sea level (MSL) in instrument meteorological conditions (IMC) with moderate to heavy rain.
Atmospheric Conditions
A temperature inversion existed between 5,000 feet and 3,000 feet MSL. According to the source, this created conditions conducive to moderate to severe clear icing. The aircraft remained in these conditions for 11.8 minutes.
Stall Event
Approximately halfway through the procedure turn, which was flown with the autopilot engaged, the captain reduced power to slow the aircraft for gear extension. At 157 knots in a clean configuration, the aircraft stalled. During the stall, the aircraft rolled 80 degrees to the left and 60 degrees to the right.
Recovery
The crew applied full power and executed stall recovery procedures. The aircraft was recovered with an altitude loss of 600 feet. The crew did not perceive any ice accretion, and the airframe deice system was not activated until after the stall.
Subsequent Approach
The third approach was conducted without incident.