What happened
A commercial pilot was performing an aerial moose survey on behalf of the State of Alaska, accompanied by a wildlife biologist. While the aircraft was in cruise flight at approximately 500 feet above the ground, the engine lost all power. The pilot attempted to restore engine power, but these efforts were unsuccessful. To avoid rising terrain, the pilot maneuvered the aircraft, which resulted in a forced landing that involved a collision with trees. Both the pilot and the passenger were not injured, though the aircraft sustained substantial damage to its wings and fuselage.
The investigation
An FAA airworthiness inspector examined the wreckage of the aircraft and collected a fluid sample from the fuel system gascolator. The sample revealed two distinct, separated layers of liquid. The upper layer was a blue-colored liquid consistent with 100LL aviation fuel, while the lower layer was a clear liquid. Upon testing the clear fluid with water finding paste, the NTSB investigator-in-charge confirmed that the sample contained water contamination.