Cessna TR182 N4777T accident near Thief River Falls, Minnesota

Probable cause

The noninstrument-rated pilot's decision to depart into instrument meteorological conditions, and his subsequent loss of control due to spatial disorientation.

NTSB analysis

The noninstrument-rated private pilot and 2 passengers departed in instrument meteorological conditions (IMC) with an overcast cloud layer at 400 ft above ground level (agl). Data obtained from an onboard GPS unit showed the airplane depart toward the destination airport and climb and descend several times. About 2 minutes after takeoff, the airplane descended to 250 ft above ground level (agl), then turned and quickly climbed to 1,400 ft agl. The final GPS points showed the airplane in a descending right turn. A witness reported hearing the airplane overhead and stated that the engine was "screaming" before impact. The airplane impacted a field about 4 minutes after takeoff resulting in a debris path about 230 yards long, consistent with a relatively high forward airspeed at the time of impact.

A postaccident examination of the airframe and engine did not reveal any preimpact anomalies that would have precluded normal operation. The primary vacuum pump was not found in the wreckage; however, an examination of the standby vacuum pump revealed that the rotor was fractured by impact, but the vanes were intact. The heading indicator and turn coordinator gyros exhibited rotational scoring consistent with rotation at the time of impact. The damage to the propeller blades was consistent with the engine producing power at impact.

The autopsy report revealed no significant coronary artery disease; however, microscopic examination revealed focal areas of fine fibrosis suggestive of prior ischemic episodes. This finding was not significant enough to suggest an incapacitating event. No other significant natural disease was present that could pose a hazard to flight safety.

Review of the pilot's logbook and his statements to individuals who spoke with him before the accident suggested that he had a history of flying in and around IMC. Given the weather conditions at the time of departure and observations of the pilot checking the weather conditions before the flight, the pilot was aware that he would be required to fly in or under IMC during the flight and chose to do so despite not holding an instrument rating. Based on the reported weather conditions and GPS data, it is likely that, while maneuvering on course after takeoff, the pilot entered IMC; he likely subsequently experienced spatial disorientation, which resulted in a loss of control and descent into terrain.

Text from the NTSB. Open the NTSB docket for CEN17FA361 for the full record.