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Atlas / NTSB / LAX86LA142

NTSB CAROL · Event

Event LAX86LA142

1986-03-16 POTERVILLE, California, United States None 1 aircraft Status: Completed

Aircraft involved

Factual narrative

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. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12

Verbatim from NTSB's published report. Source file NTSB_1986_LAX86LA142.txt. Findings + structured fields enriched from FAA avall.mdb. Full investigation docket on data.ntsb.gov ↗.