Cessna 180 N7620A accident near St Louis, Missouri

Probable cause

A total loss of engine power due to improper maintenance of the mixture control cable and attachment hardware, which led to a forced landing into a congested area.

NTSB analysis

While in cruise flight, the pilot reported hearing a loud “pop,” and the engine suddenly lost power. The pilot executed a forced landing toward a lacrosse field surrounded by residences. The airplane impacted terrain in a nose-down attitude, which substantially damaged both wings and seriously injured the pilot.

A postaccident examination revealed that the carburetor mixture control cable was disconnected from the carburetor control lever at the carburetor, with the attachment hardware (bolt, nut, and washer stack) still attached to the carburetor. No other anomalies were found that would have precluded normal operation.

Laboratory analysis of the mixture control cable and attachment hardware (bolt, nut, and washer stack) determined that the hardware was used repeatedly in numerous configurations, and the cable did not have a kink at the end indicating it had not been bent. The maintenance manual specified that the cable was to be bent 90 degrees after being threaded through the bolt hole to help secure the cable, and not doing so likely contributed to the cable becoming disconnected from the carburetor control lever inflight.

Text from the NTSB. Open the NTSB docket for CEN20LA360 for the full record.