Navion NAVION N4418K accident near Lompoc, California

Probable cause

A total loss of engine power after takeoff for reasons that could not be determined because postaccident examination did not reveal any anomalies that would have precluded normal operation.

NTSB analysis

After the airplane took off and turned downwind, the engine began to lose power. The pilot activated the boost pump, but this was followed by a total loss of engine power. The pilot then elected to return to the departure runway, but after he realized that he had insufficient altitude to reach the runway, he chose to land in an open field. Following touchdown, the airplane sustained substantial damage to the aft fuselage after sliding about 80 feet before coming to rest upright. A postaccident examination of the carburetor, boost pump, and relief valve revealed no anomalies that would have precluded normal operation. Although the airplane was operating in a regime where it may be susceptible to serious carburetor icing at cruise power, the engine was operating at higher power setting, and there was no evidence that carburetor icing played a role in the accident. The reason for the loss of engine could not be determined.

Text from the NTSB. Open the NTSB docket for WPR12LA434 for the full record.