Accident Hiller UH-12E N400AH,
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ASN Wikibase Occurrence # 371808
 
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Date:Saturday 2 January 1988
Time:17:30 LT
Type:Silhouette image of generic UH12 model; specific model in this crash may look slightly different    
Hiller UH-12E
Owner/operator:Private
Registration: N400AH
MSN: 1177
Total airframe hrs:6732 hours
Engine model:LYCOMING TIVO-540-A2A
Fatalities:Fatalities: 0 / Occupants: 3
Aircraft damage: Substantial
Category:Accident
Location:Vernal, UT -   United States of America
Phase: En route
Nature:Executive
Departure airport:Vernal, UT (KVEL)
Destination airport:
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
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.

Probable Cause:

Accident investigation:
cover
  
Investigating agency: NTSB
Report number: DEN88LA046
Status: Investigation completed
Duration: 1 year and 2 months
Download report: Final report

Sources:

NTSB DEN88LA046

History of this aircraft

Other occurrences involving this aircraft
31 August 1983 N400AH Craig Heliicopters, Inc. 0 Manning, ND sub
1 November 1985 N400AH Private 0 Vernal, UT sub

Location

Revision history:

Date/timeContributorUpdates
26-Mar-2024 10:25 ASN Update Bot Added

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