NTSB Identification: LAX94FA197.
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Accident occurred Monday, April 18, 1994 in HANAPEPE, HI
Probable Cause Approval Date: 04/07/1995
Aircraft: HUGHES 369D, registration: N1103N
Injuries: 1 Fatal,4 Serious.

NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.

THE PILOT REPORTED THAT WHILE MANEUVERING NEAR A WATERFALL ON A SIGHT-SEEING FLIGHT, THE HUGHES 369D SUSTAINED A LOSS OF ENGINE POWER, DESCENDED, AND LANDED HARD ON ROUGH/ROCKY TERRAIN. AN EXAM OF THE ENGINE REVEALED THE FUEL NOZZLE STRAINER WAS CONTAMINATED AND BLOCKED WITH SODIUM, AND IT WAS PARTIALLY COLLAPSED. TESTS OF THE NOZZLE REVEALED THAT FLOW RATES WERE BELOW THE MANUFACTURER'S SPECIFICATIONS. THE HELICOPTER WAS BEING OPERATED EXCLUSIVELY IN A MARINE ENVIRONMENT AND THE OPERATOR PERFORMED COMPRESSOR WASH PROCEDURES ON A DAILY BASIS. IN A SERVICE LETTER, THE ENGINE MANUFACTURER PRESCRIBED TURBINE ENGINE COMPRESSOR WASH PROCEDURES WHICH RESULTED IN 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 2500 HOURS, BUT ACCORDING TO THE MANUFACTURER, IT WAS NOT SUBJECT TO ANY PRIOR ROUTINE INSPECTION REQUIREMENT.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

INADEQUATE TURBINE ENGINE COMPRESSOR CLEANING PROCEDURES BASED ON INFORMATION IN THE MANUFACTURER'S SERVICE LETTER, AND LOSS OF ENGINE POWER DUE TO BLOCKAGE OF THE FUEL NOZZLE STRAINER WITH FOREIGN MATERIAL (SODIUM). FACTORS RELATED TO THE ACCIDENT WERE: THE LACK OF A SPECIFIED SERVICE REQUIRMENT FOR INSPECTION OF THE FUEL STRAINER, AND TERRAIN CONDITIONS IN THE EMERGENCY LANDING AREA.

Full narrative available

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