Cessna U206E N1457M accident near Oroville, California

Probable cause

A total loss of engine power during cruise flight due to an excessively lean mixture for undetermined reasons.

NTSB analysis

The airplane owner/pilot departed for a personal flight with 55 gallons of fuel in the airplane's fuel tanks. After flying for nearly 40 minutes all engine power was suddenly lost. The pilot reported that, because he was only 1,100 feet above the ground, he had limited time to attempt an engine restart. Therefore, the pilot concentrated on performing the forced landing. The pilot landed in an open field. During rollout on the uneven terrain, the nose gear collapsed and the firewall was bent. Subsequently, the airplane was recovered and examined and no anomalies were found. The engine was test run and no evidence of any mechanical malfunction was noted. The airplane was equipped with an engine monitoring system that retained various engine related operating parameters. The extracted nonvolatile memory data revealed that the engine's exhaust gas temperature peaked a few seconds before the fuel flow decreased to zero and all power was lost. The data was consistent with an interruption of fuel flow to the engine due to an overly lean mixture; however, the investigation could not determine the cause of the excessively lean mixture.

Text from the NTSB. Open the NTSB docket for WPR09LA237 for the full record.