NTSB Identification: LAX85FA136.
The docket is stored on NTSB microfiche number 28473.
Accident occurred Tuesday, February 05, 1985 in HILO, HI
Aircraft: HUGHES 369D, registration: N369LA
Injuries: 1 Fatal.

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.

A SEARCH WAS INITIATED WHEN THE HELICOPTER DID NOT ARRIVE. IT WAS FND 2 DAYS LATER WHERE IT CRASHED DRG AN AUTOROTATION IN A RAIN FOREST. DRG THE FLARE/TOUCHDOWN, VEGETATION HAD CAUGHT ON A TUNDRA PAD ON THE L SKID & THE ACFT ROLLED OVER. AN EXAM REVEALED THE LWR BENDIX COUPLING ON THE ENG-TO-TRANSMISSION DRIVE SHAFT, PN 369A4410, & THE UPPER R ENG MOUNT, PN 369H8017, HAD FAILED. UNAPPROVED MOD/REPAIRS HAD BEEN MADE TO BOTH THE DRIVE SHAFT & OVERLYING COVER PANEL. A STEEL REINFORCING ROD HAD BEEN INSTALLED INSIDE THE COVER PANEL. DUE TO PRESSURE OF CARGO (LARGE WTR BUCKET), THE STEEL ROD HAD BEEN FORCED ONTO THE DRIVE SHAFT. THERE WAS EVIDENCE OF ANGULAR MISALIGNMENT & LATER FAILURE OF THE DRIVE SHAFT. A METALLURGICAL EXAM OF THE ENG MOUNT REVEALED LOW CYCLIC FATIGUE IN THE THREADED ROD AREA OF THE ADJUSTING SCREW. THE FRACTURE AREA OF THE DRIVE SHAFT WAS TOO BADLY DAMAGED TO DETERMINE THE MODE OF FAILURE. ACFT PREV OPERD IN CANADA, REG C-GVTJ. ANNUAL INSPN & U.S. AIRWORTHINESS CERTIFICATE ISSUED DESPITE UNAPPROVED MOD. DATE OF MOD UNKNOWN.

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

MAINTENANCE,MODIFICATION..IMPROPER..OTHER MAINTENANCE PERSONNEL

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

FUSELAGE,FAIRING..DISTORTED

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

AIRCRAFT PREFLIGHT..INADEQUATE..PILOT IN COMMAND

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

ROTOR DRIVE SYSTEM,ENGINE TO TRANSMISSION DRIVE..WORN

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

ROTOR DRIVE SYSTEM,ENGINE TO TRANSMISSION DRIVE..FAILURE,TOTAL

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

ENGINE ASSEMBLY,MOUNT..FAILURE,TOTAL



Contributing Factors

TERRAIN CONDITION..NONE SUITABLE


Contributing Factors

TERRAIN CONDITION..HIGH VEGETATION


Contributing Factors

TERRAIN CONDITION..MOUNTAINOUS/HILLY


Contributing Factors

MAINTENANCE,INSPECTION..INADEQUATE


Contributing Factors

OBJECT..TREE(S)

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