What happened
During a ferry flight, the crew switched the fuel source to a chemical hopper that had been modified to serve as a fuel tank. Shortly after this transition, the engine failed. The pilot was unable to restart the engine and subsequently performed a forced landing in a wooded area.
The investigation
Following the accident, investigators examined the engine's operation. Post-crash testing demonstrated that the engine would not run when utilizing the engine driven fuel pump. However, after the fuel pump was replaced, the engine operated normally.
An inspection of the failed engine driven pump revealed black rubber particle contamination located under the bypass valve. Additionally, the pump was found to be worn, a condition that prevented the necessary buildup of fuel pressure. The investigation noted that the fuel line from the hopper tank entered the airframe fuel system downstream of the electric boost pump; consequently, the engine driven pump served as the sole source of fuel pressure for the hopper tank.