ERA17LA278 · Piper PA28 180

The private pilot was conducting a solo cross-country personal flight. The pilot reported that, when the airplane was about 10 miles from the destination airport, he moved the mixture control handle and that it felt like it caught on something. He pushed on the handle harder until it moved to full rich, but the engine power reduced to idle. He added that, while attempting to troubleshoot the problem by moving the mixture control handle back to the point where he thought it had gotten caught to see if would happen again, he heard a "pop" sound, followed by a partial loss of engine power. His attempts to restore engine power were unsuccessful. He then maneuvered the airplane for a forced landing in a field, during which the left wing sustained substantial damage.

Postaccident examination of the engine compartment by the pilot, who was also a certificated mechanic and had performed the airplane's last 100-hour inspection, revealed that the mixture control cable had separated from the mixture control lever at the carburetor. The attachment hardware was not recovered. The pilot reported that, when he inspected the engine controls at the carburetor during the 100-hour inspection (about 30 to 40 flight hours before the accident flight), they were all properly secured. No maintenance was conducted on the mixture control at the carburetor after the inspection was completed. The separation of the mixture control cable from the mixture control lever at the carburetor likely resulted in the partial loss of engine power. The reason for the separation of the mixture control cable from the mixture control lever at the carburetor could not be determined because the attachment hardware was not recovered.

Verbatim NTSB analysis and probable cause from the NTSB dataset