NTSB Identification: ANC90LA135.
The docket is stored on NTSB microfiche number 42875.
Accident occurred Tuesday, August 07, 1990 in TOK, AK
Probable Cause Approval Date: 06/19/1992
Aircraft: AEROSPATIALE SA-315B, registration: N58000
Injuries: 1 Serious.

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 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.

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

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.

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