Hiller UH-12E N400AH

Summary

On 2 January 1988 at about 22:30 local time, a Hiller UH-12E registered N400AH was involved in an accident near Vernal, Utah, United States. 3 people were on board and nobody was injured. The aircraft was substantially damaged. No probable cause statement is available for this record.

Date

2 January 1988 at 22:30

Classification

Accident

Location

Vernal, Utah, United States

Coordinates

40.5490, -109.5700

Aircraft

Hiller UH-12E

Registration

N400AH

Category

Helicopter

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Business

Phase of flight

Not recorded

Route

Vernal → Unknown

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

DEN88LA046

Nobody was injured.

The NTSB has not published a probable cause for this record. No probable cause statement is present in the source data.

Nothing about the cause is stated here that is not in the source record.

Read the full NTSB 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.

Quoted verbatim from the NTSB record.