Cessna 172 N8488L accident near Cottage Grove, Minnesota

Probable cause

A steep descent and impact with terrain for reasons that could not be determined based on the available information.

NTSB analysis

The accident flight was a “discovery flight” arranged by the rear seat passenger for his girlfriend, the front seat passenger. A flight instructor was seated in the right front seat. Flight track information revealed that, about four minutes after departure at an altitude of about 1,900 ft, the airplane entered a steep descent that continued until water contact. The airplane was destroyed when it impacted the water.

Examination of the airplane revealed no evidence of mechanical anomalies that would have precluded normal operation, and no evidence of a bird strike. Visual meteorological conditions were present in the area at the time of the accident.

Available medical information provided no evidence that the CFI had any medical condition,

substance use, or toxic exposure that contributed to the accident. Based on the absence of detected

ethanol in the CFI’s urine, it is likely that ethanol detected in his cavity blood was from sources other

than ingestion.

Given the available information, the reason for the airplane’s impact with terrain could not be determined.

Text from the NTSB. Open the NTSB docket for CEN20LA392 for the full record.