Incident Overview
An aircraft experienced a loss of engine power, necessitating a forced landing. During the landing, the aircraft contacted a tree and a large bale of hay. The circumstances leading to the power loss were investigated through a post-accident inspection.
Fuel System Examination
Following the accident, inspectors examined the aircraft's fuel system. Measurements revealed that 18 gallons of fuel remained in the left main tank and 3 gallons remained in the left wing tip tank. Both right wing fuel tanks were ruptured. A very small amount of fuel was found in the fuel lines, and the fuel strainer bowl at the bottom of the fuel selector valve was empty.
Fuel Selector Valve Condition
Detailed examination of the fuel selector valve disclosed that the valve seat to the right tip tank was coated with dirt and debris. This contamination prevented the valve from seating properly. The source noted that this condition would allow the engine-driven fuel pump to draw air when the right tip tank was emptied.
Conclusion
The aircraft's forced landing and subsequent collision with a tree and a hay bale occurred after a loss of engine power. The inspection identified fuel distribution issues and a contaminated fuel selector valve.