Introduction
A single-engine aircraft experienced a power loss during cruise flight, resulting in an emergency landing on a highway. The aircraft struck trees and crashed into terrain. Post-accident examination revealed a mechanical issue with the fuel selector valve.
Event Sequence
The pilot reported that the aircraft was fueled before departure. Approximately two hours after takeoff, the engine began to run roughly. The pilot observed a drop in fuel pressure and switched fuel tanks in an attempt to resolve the issue. Despite these efforts, the engine stopped producing power. The pilot was forced to attempt an emergency landing on a highway. During the landing attempt, the aircraft struck trees and subsequently crashed into the terrain.
Examination Findings
Examination of the aircraft's fuel selector valve disclosed that the detent washer was broken, with approximately one-quarter of the washer missing. As a result, there was no noticeable detent; the selector rotated freely and could be easily moved to a position between tanks or to the 'off' position.
Probable Cause
No probable cause was determined in the source material.