Incident Summary
An aircraft en route to Salt Lake City (SLC), where it was scheduled to be placed on static display with other aircraft equipped with Soloy conversions (Allison 250-C20S turboshaft engine installation), experienced an engine flameout and subsequent surges during descent. The pilot executed a forced landing on a mud flat in the Great Salt Lake.
Sequence of Events
During descent through 12,000 feet into the SLC area, the engine flamed out and the propeller auto-feathered. The pilot successfully restarted the engine, but upon advancing the power lever, the engine surged and quit. The pilot restarted the engine again and turned on engine anti-ice. When power was advanced, the engine surged and quit once more. After restarting the engine a third time, the pilot applied alternate air. When power was advanced, the engine surged, and power dropped to idle. The pilot then turned off engine anti-ice and alternate air, pulled the auto-feather circuit breaker, switched the start/motor switch to start, and attempted to advance power. The engine continued to surge. Subsequently, the pilot made a forced landing on a mud flat in the Great Salt Lake.
Investigation Findings
Disassembly, examination, and testing of the engine, fuel control, power turbine governor, and fuel revealed no discrepancies. However, examination of the fuel flow transducer revealed a partial blockage. The blockage was blown out during inspection and was never found; therefore, it could not be identified.
Conclusion
No probable cause was stated in the investigation source.