NTSB Identification: LAX90LA050.
The docket is stored on NTSB microfiche number 42409.
Accident occurred Friday, December 08, 1989 in WAIMEA, HI
Probable Cause Approval Date: 09/09/1992
Aircraft: HUGHES 369HS, registration: N9161F
Injuries: 5 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

THE CERTIFICATED AIR LINE TRANSPORT PILOT WAS CONDUCTING A HELICOPTER SIGHTSEEING FLIGHT WITH 4 PASSENGERS WHEN THE ENGINE SUDDENLY LOST POWER. THE PILOT MADE AN EMERGENCY AUTOROTATION TO THE BOTTOM OF A SMALL RIVER BOTTOM. WHILE LANDING, THE HELICOPTER ROLLED OVER. EXAMINATION OF THE ENGINE SHOWED THAT THE FUEL CONTROL PC TUBE TO THE POWER TURBINE GOVERNOR HAD FRACTURED, CAUSING THE ENGINE TO GO TO A FLIGHT IDLE CONDITION. THIS TUBE WAS FOUND TO EXCEED THE SPECIFIED REQUIRED LENGTH OF MANUFACTURE. DURING INSTALLATION, THE TUBE WAS BENT BY COMPANY MAINTENANCE PERSONNEL TO FIT. METALLURGICAL EXAM DISCLOSED A FRACTURE DUE TO FATIGUE NEAR THE FUEL CONTROL END. THIS FATIGUE WAS INTRODUCED BY BENDING STRESSES IN THE TUBE.

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

THE IMPROPER INSTALLATION OF THE PC TUBE BY COMPANY MAINTENANCE PERSONNEL, WHICH RESULTED IN FATIGUE FAILURE OF THE TUBE DUE TO INDUCED BENDING STRESSES.

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