NTSB Identification: LAX86FVM06.
The docket is stored on NTSB microfiche number 31537.
Accident occurred Tuesday, August 12, 1986 in SALINAS, CA
Aircraft: HILLER UH21E, registration: N169HA
Injuries: 1 Uninjured.

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 PLT EXPERIENCED A 'RATCHETING' TO THE RIGHT AND A DECREASE IN ROTOR RPM DURING CRUISE FLT AT 75-100 FT AGL. THE PLT MADE AN AUTOROTATION BUT COULD NOT CUSHION THE LANDING DUE TO THE LOW ALT AND LACK OF ROTOR RPM. THE HELICOPTER IMPACTED HARD AND CARTWHEELED. POST ACCIDENT EXAMINATION OF THE HELICOPTER REVEALED THE UPPER HOUSING OIL ORIFICE WAS COMPLETELY BLOCKED WITH A FOREIGN MATERIAL WHICH RESULTED IN OIL STARVATION TO THE SECONDARY PLANET SYSTEM. THE FOREIGN MATERIAL WAS ANALYZED AND FOUND TO CONTAIN 'SIGNIFICANT QUANTITIES OF SILICON'.

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

LUBRICATING SYSTEM..BLOCKED(TOTAL)



Contributing Factors

ROTOR RPM..INADEQUATE

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