NTSB Identification: DEN88LA046.
The docket is stored on NTSB microfiche number 35499.
Accident occurred Saturday, January 02, 1988 in VERNAL, UT
Probable Cause Approval Date: 03/30/1989
Aircraft: HILLER UH-12E, registration: N400AH
Injuries: 3 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 COMMERCIAL PLT AND TWO PASSENGERS WERE SURVEYING A ROAD ROUTE IN MOUNTAINOUS TERRAIN. AT CRUISE, THE PILOT NOTICED A DROP IN MANIFOLD PRESSURE, FOLLOWED BY A LOSS OF OIL PRESSURE. THE PLT REPORTED THAT THE ENGINE QUIT. AN AUTOROTATION TO A SNOW COVERED ROAD RESULTED IN A HARD LANDING. THE MAIN ROTOR BLADES SEVERED THE TAIL BOOM AND THE LANDING SKIDS COLLAPSED. A POST ACCIDENT ENGINE TEAR DOWN REVEALED EVIDENCE CONSISTENT WITH CONNECTING ROD FAILURE. THE NUMBER FIVE ROD BEARING HAD DISINTEGRATED AND THE ROD END CAP HAD BROKEN IN SERVICE. THE DAMAGED ROD END CAP AND CONNECTING ROD WERE EXAMINED FOR FAILURE MODE DETERMINATION. THE METALLURGIST'S FACTUAL REPORT STATES THAT THE ROD SHOWS FRACTURE DETAILS CHARACTERISTICS OF HIGH CYCLE FATIGUE.

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

ENGINE ASSEMBLY,CONNECTING ROD..FATIGUE

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

ALTITUDE..MISJUDGED..PILOT IN COMMAND

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

FLARE..IMPROPER..PILOT IN COMMAND

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

MAINTENANCE,REBUILD/REMANUFACTURE..POOR..OTHER MAINTENANCE PERSONNEL

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

ENGINE ASSEMBLY,CONNECTING ROD BOLT..STRIPPED THREAD

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

ENGINE ASSEMBLY,CONNECTING ROD CAP..FAILURE,TOTAL


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