Incident Description
During a sightseeing flight, a Hughes 369D helicopter was maneuvering near a waterfall when it experienced a loss of engine power. The helicopter descended and landed hard on rough, rocky terrain.
Examination Findings
An examination of the engine revealed that the fuel nozzle strainer was contaminated and blocked with sodium. The strainer was also partially collapsed. Tests of the nozzle showed that fuel flow rates were below the manufacturer's specifications.
Maintenance Context
The helicopter was operated exclusively in a marine environment. The operator performed compressor wash procedures on a daily basis. A service letter from the engine manufacturer prescribed turbine engine compressor wash procedures that resulted in the immersion of the fuel nozzle in contaminated wash water. There was evidence of subsequent infiltration of wash water into the fuel nozzle strainer. The fuel nozzle strainer had a life limit of 2,500 hours, but according to the manufacturer, it was not subject to any prior routine inspection requirement.