NTSB Identification: LAX86LA142.
The docket is stored on NTSB microfiche number 30308.
Accident occurred Sunday, March 16, 1986 in POTERVILLE, CA
Aircraft: HILLER 12E, registration: N90475
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.

A HILLER 12E HELICOPTER LANDED HARD AFTER AN ENG FAILURE. THE ACFT WAS ENROUTE TO ANOTHER FIELD SITE AT APRX 100 FT AGL AND 40 KTS IAS. THE ENG QUIT ABRUPTLY AND THE ROTOR RPM DECAYED 100 RPM. THE ACFT WAS ABOUT 2,000 POUNDS GWT AT THE TIME OF THE ACCIDENT AND THE AUTOROTATIONAL RPM WAS RIGGED FOR THE MAXIMUM GWT OF 3,100 POUNDS. THE ENG MAIN CASE WAS CRACKED IN THE VICINITY OF CYL #6. DURING THE ENG TEARDOWN #6 PISTON, CONNECTING ROD AND ONE RODCAP BOLT CAME OFF WITH THE CYL. ONE ROD BOLT WAS BROKEN AND THE NUT WAS STILL ATTACHED TO THE BROKEN END. THE OTHER ROD BOLT WAS UNBROKEN AND THE NUT WAS MISSING.

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

ENGINE ASSEMBLY..FAILURE,TOTAL

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

ENGINE ASSEMBLY,CONNECTING ROD..FAILURE,TOTAL


Contributing Factors

AUTOROTATION..POOR..PILOT IN COMMAND

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