# NTSB ANC90LA135: Aerospatiale SA-315B, N58000, Tok, AK, August 7, 1990

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: August 7, 1990, 12:30 local (20:30 UTC)
- Place: Tok, AK
- Coordinates: 63.18085, -143.099975 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=63.1808&lon=-143.1000&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 1 serious
- Status: Completed, report June 19, 1992
- Report: Approved by Office Director
- NTSB office: Alaska Regional Office
- Safety recommendations: Yes
- NTSB case key (mKey): 5420
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC90LA135
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/5420/pdf
- Page: https://openairdocs.org/ntsb/ANC90LA135

## 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.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Loss of engine power(total) - nonmechanical, hover
  - fuel system,filter - other (cause)
  - acft/equip,inadequate design, manufacturer (contributing factor)
  - maintenance,installation - improper, company maintenance personnel (cause)
  - lack of familiarity with aircraft, company maintenance personnel (contributing factor)
  - fluid,fuel - contamination (cause)
- Forced landing, descent - emergency
  - autorotation - performed, pilot in command
- Hard landing, landing

## Analysis

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.

## Aircraft

- Registration: [N58000](https://openairdocs.org/aircraft/N58000), registered now, S/N 2639 (OpenAirDocs)
- Reported make and model: AEROSPATIALE SA-315B
- Registry model: [Aerospatiale SA315B](https://openairdocs.org/model/aerospatiale-sa315b) (registry code 8680615) (OpenAirDocs)
- Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs)
- Category: Helicopter
- Serial number: 2639
- Airframe hours: 3607
- Engines: TURBOMECA ARTOUSTE IIIB 878 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Other work use, Part 133
- Registered owner: Pegasus Helicopters, Inc.
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, August 4, 1990, 17 hours before
- Departed: TKJ, TOK, AK
- Flight plan: Company VFR
- Airport: NONE

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 43; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: right; flight hours: 13,000 total, 5,000 in this make and model, 13,000 as pilot in command, 265 in the last 90 days, 98 in the last 30 days, 4 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 220° at 10 knots, gusting 12
- Visibility: 50 statute miles
- Lowest ceiling: 5,000 ft broken
- Temperature: 63 °F, dew point -0 °F
- Altimeter: 29.00 inHg

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19900807031499A](https://openairdocs.org/incident/19900807031499A), Aug 7, 1990: Aerosp SA315B, Tok, AK, Substantial damage. Engine quit at hover with external load. Made hard landing. Fuel filter element installed upside down by pilot.

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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