NTSB Identification: LAX97LA088.
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Accident occurred Sunday, January 12, 1997 in KAMUELA, HI
Probable Cause Approval Date: 02/02/1998
Aircraft: McDonnell Douglas 369D, registration: N7012G
Injuries: 1 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 helicopter was being operated in a marine environment. The pilot reported he lost engine power during the initial takeoff climb and autorotated to an open field. The helicopter landed hard and the main rotor blades severed the tailboom. Examination of the engine fuel filter, the fuel control unit (FCU) screen, and the fuel nozzle screen revealed contamination in the fuel system. The helicopter had been inspected in accordance with the manufacturer's 100/300 hour inspection about 21.2 flight hours before the accident. There were no reports of the engine fuel filter bypassing or the fuel filter caution light illuminating. The manufacturer's inspection program does not require the inspection of the fuel screens at the 100 or 300 hour intervals. The airframe manufacturer's maintenance manual does indicate that a conditional inspection be performed after the fuel filter caution light has illuminated. Review of the conditional inspection procedures revealed the FCU screen is to be removed and cleaned; however, there is no requirement for the removal and cleaning of the nozzle screen, which is downstream of the FCU screen, before the part's 2,500 hour overhaul cycle.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: fuel system contamination resulting in a partial loss of power, and the failure of the pilot to maintain adequate rotor rpm to cushion the autorotative landing and prevent main rotor blade contact with the tailboom. Factors were the inadequacy of manufacturer's maintenance inspection procedures for aircraft operated in a marine environment. Full narrative available
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