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Aviation safety reports, made easier to study

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NTSB Report

August 7, 1990 · Aerospatiale SA-315B · N58000

Tok, AK

Overview

Report Status
Probable Cause
Event Type
Accident
Date
August 7, 1990
Injury Outcomes
1 injury (1 serious injury)
Location
Tok, AK
Aircraft
Aerospatiale SA-315B
Tail Number
N58000
Injuries
Serious
Aircraft Damage
Substantial
NTSB Number
ANC90LA135

THE HELICOPTER WAS BEING USED IN AN EXTERNAL LOAD OPN TO CARRY CARGO WITH A 100 FT CABLE. WHILE HOVERING OUT OF GROUND EFFECT, THE ENG LOST PWR. A SUBSEQUENT HOVERING AUTOROTATION RESULTED IN A HARD LANDING. AN EXAM REVEALED THE LOSS OF POWER WAS DUE TO FUEL CONTAMINATION ALTHOUGH AN AIRFRAME FUEL FILTER WAS INSTALLED IN THE MAIN FUEL SUPPLY LINE. AN EXAM REVEALED THE FILTER ELEMENT HAD BEEN INSTALLED BACKWARD IN THE FILTER CANISTER. THIS ALLOWED CONTAMINATED FUEL TO BYPASS THE FILTER ELEMENT & ENTER THE ENG FUEL CTL UNIT. THE REVERSE INSTLN ALSO RESULTED IN AN INOP 'FUEL FILTER CLOGGED' WARNING LGT & PREVENTED THE PRESSURE DIFFERENTIAL BUTTON ON THE FILTER HOUSING FM EXTDG. THE FILTER HAD BEEN INSPECTED & REINSTLD DRG A 100 HR INSPN, 17 FLT HRS BFR THE ACDNT. THIS WORK WAS DONE BY A PLT UNDER SUPERVISION OF A MECHANIC. THE MECHANIC HAD NO PREV EXPERIENCE WITH THIS MAKE & MODEL OF HELICOPTER. 'TOP' & 'BOTTOM' WERE STENCILED ON THE FILTER ELEMENT IN FRENCH. CONTAMINATED FUEL WAS ALSO FND IN THE FUEL TRUCK.

NTSB Probable Cause

IMPROPER INSTALLATION OF THE FUEL FILTER ELEMENT IN THE AIRCRAFT BY COMPANY/MAINTENANCE PERSONNEL, AND SUBSEQUENT CONTAMINATION OF THE FUEL SYSTEM BY UNFILTERED FUEL. FACTORS RELATED TO THE ACCIDENT WERE: INADEQUATE DESIGN OF THE FUEL FILTER ASSEMBLY, WHICH ALLOWED THE IMPROPER INSTALLATION OF THE FILTER ELEMENT, THE MECHANICS LACK OF FAMILIARITY WITH THE AIRCRAFT, AND FAILURE OF GROUND PERSONNEL TO INSURE THAT FUEL FROM THE FUEL TANKER WAS FREE OF CONTAMINATION.

Full Narrative

THE HELICOPTER WAS BEING USED IN AN EXTERNAL LOAD OPN TO CARRY CARGO WITH A 100 FT CABLE. WHILE HOVERING OUT OF GROUND EFFECT, THE ENG LOST PWR. A SUBSEQUENT HOVERING AUTOROTATION RESULTED IN A HARD LANDING. AN EXAM REVEALED THE LOSS OF POWER WAS DUE TO FUEL CONTAMINATION ALTHOUGH AN AIRFRAME FUEL FILTER WAS INSTALLED IN THE MAIN FUEL SUPPLY LINE. AN EXAM REVEALED THE FILTER ELEMENT HAD BEEN INSTALLED BACKWARD IN THE FILTER CANISTER. THIS ALLOWED CONTAMINATED FUEL TO BYPASS THE FILTER ELEMENT & ENTER THE ENG FUEL CTL UNIT. THE REVERSE INSTLN ALSO RESULTED IN AN INOP 'FUEL FILTER CLOGGED' WARNING LGT & PREVENTED THE PRESSURE DIFFERENTIAL BUTTON ON THE FILTER HOUSING FM EXTDG. THE FILTER HAD BEEN INSPECTED & REINSTLD DRG A 100 HR INSPN, 17 FLT HRS BFR THE ACDNT. THIS WORK WAS DONE BY A PLT UNDER SUPERVISION OF A MECHANIC. THE MECHANIC HAD NO PREV EXPERIENCE WITH THIS MAKE & MODEL OF HELICOPTER. 'TOP' & 'BOTTOM' WERE STENCILED ON THE FILTER ELEMENT IN FRENCH. CONTAMINATED FUEL WAS ALSO FND IN THE FUEL TRUCK.

Flight

Event TypeAccident
Event Time12:30 AKDT
Nearest Airport0nm N
Runway0
Flight Plan FiledCvfr
Aircraft FireNo
Aircraft ExplosionNo

Aircraft

AircraftAerospatiale SA-315B
Tail NumberN58000
Aircraft CategoryHeli
DamageSubstantial
Operating RulePart 133
Engines1
Engine TypeTurboshaft
Engine DetailsTurbomeca · ARTOUSTE IIIB · Turboshaft · 878
Seats5

People & Injuries

Injury Summary1 injury (1 serious injury)
Fatal0
Serious1
Minor0
Uninjured0
Total1
Crew 1Age 43 · Second Class

Conditions

ConditionsVMC
LightDaylight
Wind220° @ 10 kt, gusting 12 kt
Visibility50 sm
CeilingBroken clouds 5000 ft
Temperature / Dew Point63 F / 0 C
Altimeter29.00 inHg
Weather SourceWIT

Appendix: Source Data