WPR23FA188 · Cessna T182T

The pilot and passenger departed the airport on an instrument flight rules (IFR) flight in an airplane that was prohibited from flight into icing conditions and over the maximum takeoff weight. Instrument meteorological conditions (IMC) prevailed and included forecasted moderate icing conditions, mountain obscurations, moderate turbulence, and cloud formations from about 8,300 ft mean sea level (msl) to 18,000 ft. About 30 minutes after departure while enroute at 13,000 ft, the pilot reported mild ice to the air route controller but stated that they were “OK.” The airplane remained on the assigned route and altitude for about the next 17 minutes, when it gradually slowed from its cruise speed by about 20 knots without an indication of a reduction of power. The airplane then turned right, off course, and began to descend from its assigned altitude. Engine data monitor (EDM) data showed that, about that time, the pilot added power above the cruise power setting. The airplane stopped turning but continued heading off course while descending for about 1 mile. The air route controller made multiple altitude alerts and advised the pilot to climb immediately. The pilot only advised the controller that he had a problem. The airplane continued deviating away from the assigned route and descending, while the groundspeed of the airplane varied. The airplane entered a descending, tightening right turn with climb power applied. The airplane remained in the descending, tightening right turn at descent rates of up to 1,825 ft per minute until the last recorded data point at 965 ft above ground level (agl), located about 890 ft north of the accident site. Postaccident examination of the airframe and engine revealed no evidence of preexisting mechanical malfunctions or anomalies that would have precluded normal operation. Lack of maintenance records precluded the investigation from determining the status of the attitude indicator. The pilot and passenger were returning from a trip that occurred over several days and consisted of multiple flight legs and included weather delays. The day of the accident was to be the final day of the trip. Departing on the flight while moderate icing conditions were forecast, and continuing along the flight route after experiencing ice accretion on an airplane prohibited from operating in icing conditions, are consistent with poor aeronautical decision making. The continuous right turn with a reducing radius suggests that the pilot remained in IMC conditions during the descent and may have experienced spatial disorientation while also reacting to the stall recovery; however, the airplane’s steep impact angle, minimal debris field, and damage signatures were consistent with a stall/spin event when the accident occurred.

Verbatim NTSB analysis and probable cause from the NTSB dataset