What happened
Shortly after departing, the pilot reported that the engine began losing power. While the engine did not quit completely, it remained at a level barely above idle. Passengers on board noted that the engine continued to run smoothly at this partial power without sputtering.
The pilot was unable to restore power to the engine and subsequently executed a forced landing at a nearby golf course. Because golfers were present on the fairways, the pilot could not utilize the fairway for the landing. The aircraft instead struck rough terrain and traveled through a ravine, resulting in substantial damage to the aircraft. No injuries were reported.
The investigation
An examination of the aircraft confirmed that fuel was available in all four fuel tanks prior to the impact damage. Investigators inspected the fuel lines leading to the engine-driven fuel pump and found them to be intact with no evidence of leakage.
Testing of the fuel system showed that the electric boost pump operated and indicated normal fuel pressure. Additionally, the engine-driven fuel pump was bench tested and found to be operating normally. A subsequent test run of the engine demonstrated that it operated within all required specifications.