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Aviation safety reports, made easier to study

NTSB Reports is an independent research and search tool for public aviation accident and incident records. It brings NTSB aviation reports, structured fields, docket files, extracted figures, photos, videos, and update history into one searchable interface.

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NTSB Report

June 12, 1986 · Bell 47G-2 · N11VH

Zillah, WA

Overview

Report Status
Preliminary report
Event Type
Accident
Date
June 12, 1986
Injury Outcomes
No injuries (1 uninjured)
Location
Zillah, WA
Aircraft
Bell 47G-2
Tail Number
N11VH
Injuries
None
Aircraft Damage
Destroyed
NTSB Number
SEA86LA143

EN ROUTE TO THE LOCAL SPRAY AREA A TOTAL LOSS OF POWER OCCURRED ALONG WITH A LOSS OF OIL PRESSURE. THE ACFT WAS APRX 200 FT AGL OVER A PEAR ORCHARD. THE PLT WAS ATTEMPTING TO AUTOROTATE ONTO A NEARBY ROAD BUT THE LEFT SKID CAUGHT THE ROOF TOP OF A METAL SHED. THE HELICOPTER CRASHED THROUGH THE ROOF OF THE SHED AND ROLLED OVER ONTO ITS SIDE. INVESTIGATION REVEALED THAT THE NUMBER THREE CYLINDER ROD BOLT HAD FAILED. METALLURGICAL EXAM REVEALED THAT THE NUMBER 3 CYLINDER CONNECTING ROD CAP HAD FAILED AS A RESULT OF OVERSTRESS FORCES DUE TO EXCESSIVE HEATING OF THE ROD AND CAP. FAILURE OF THE NUMBER 3 CYLINDER CONNECTING ROD BOLT WAS DUE TO FATIGUE CRACKING. THE MOST LIKELY CAUSE OF THE OVERHEATING WAS DUE TO A DETERIORATED BEARING.

Full Narrative

EN ROUTE TO THE LOCAL SPRAY AREA A TOTAL LOSS OF POWER OCCURRED ALONG WITH A LOSS OF OIL PRESSURE. THE ACFT WAS APRX 200 FT AGL OVER A PEAR ORCHARD. THE PLT WAS ATTEMPTING TO AUTOROTATE ONTO A NEARBY ROAD BUT THE LEFT SKID CAUGHT THE ROOF TOP OF A METAL SHED. THE HELICOPTER CRASHED THROUGH THE ROOF OF THE SHED AND ROLLED OVER ONTO ITS SIDE. INVESTIGATION REVEALED THAT THE NUMBER THREE CYLINDER ROD BOLT HAD FAILED. METALLURGICAL EXAM REVEALED THAT THE NUMBER 3 CYLINDER CONNECTING ROD CAP HAD FAILED AS A RESULT OF OVERSTRESS FORCES DUE TO EXCESSIVE HEATING OF THE ROD AND CAP. FAILURE OF THE NUMBER 3 CYLINDER CONNECTING ROD BOLT WAS DUE TO FATIGUE CRACKING. THE MOST LIKELY CAUSE OF THE OVERHEATING WAS DUE TO A DETERIORATED BEARING.

Flight

Event TypeAccident
Event Time04:45 PDT
Nearest Airport0nm N
Runway0
Runway Length0
Runway Width0
Flight Plan FiledNone
Aircraft FireNo
Aircraft ExplosionNo

Aircraft

AircraftBell 47G-2
Tail NumberN11VH
Aircraft CategoryHeli
DamageDestroyed
Operating RulePart 137
Engines1
Engine TypeReciprocating
Engine DetailsLycoming · TVO-435-BIA · Reciprocating · 270
Seats3

People & Injuries

Injury SummaryNo injuries (1 uninjured)
Fatal0
Serious0
Minor0
Uninjured1
Total1
Crew 1Age 25 · First Class

Conditions

ConditionsVMC
LightDawn
WindCalm
Visibility50 sm
CeilingNone
Temperature / Dew Point64 F / 0 C
Altimeter29.00 inHg
Weather SourcePILO

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Appendix: Source Data