# NTSB LAX84FA095: Aerospatiale AS 355F, N57901, Black Mountain, NV, December 7, 1983

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Field investigation · Final report
- Date: December 7, 1983, 12:29 local (20:29 UTC)
- Place: Black Mountain, NV
- Coordinates: 36.159759, -115.430442 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=36.1598&lon=-115.4304&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 3 fatal
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 23914
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX84FA095
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/23914/pdf
- Page: https://openairdocs.org/ntsb/LAX84FA095

## Sequence of events

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

- Airframe/component/system failure/malfunction, takeoff - initial climb
  - engine instruments,torquemeter - inoperative (contributing factor)
  - maintenance,replacement - not performed (contributing factor)
  - cooling system,cowling - undetermined (contributing factor)
  - cooling system,cowling - separation (contributing factor)
  - turboshaft engine,free turbine governor - false indication (contributing factor)
- Forced landing, landing
  - emergency procedure - improper, pilot in command (cause)
  - wrong engine shutdown - performed, pilot in command (cause)
  - autorotation - performed, pilot in command
- Roll over, landing - flare/touchdown
  - terrain condition - mountainous/hilly (contributing factor)
  - terrain condition - rough/uneven (contributing factor)

## Analysis

THE HELICOPTER TOOKOFF ON AN AIR AMBULANCE FLT AT ABOUT 1219 PST. ACCORDING TO TOWER PERSONNEL, THE DEPARTURE APPEARED NORMAL. RADAR SERVICE WAS TERMINATED AT 1227 & THERE WAS NO FURTHER RADIO CONTACT WITH THE HELICOPTER. LATER, THE HELICOPTER WAS FOUND WHERE IT HAD CRASH LANDED ON STEEP MOUNTAINOUS TERRAIN, ROLLED OVER & BURNED. AN INVESTIGATION REVEALED AN OPEN LOGBOOK ENTRY THAT THE #1 TORQUE TRANSMITTER WAS INOP. A PERSON NEAR THE DEPARTURE POINT NOTICED THE L ENG COWLING WAS LOOSE. A SHORT TIME LATER, A 3' X 4' PIECE OF ENG COWLING WAS OBSERVED TO FALL FROM THE HELICOPTER. THERE WAS NO INDICATION IN THE AIRCREW'S RADIO TRANSMISSIONS THAT THEY WERE AWARE OF THE COWLING PROBLEM. AN EXAM REVEALED EVIDENCE THAT THE COWLING STANDOUT TUBE FOR THE L ENG HAD RUBBED AGAINST THE FREE WHEELING TURBINE GOVERNOR CABLE. AEROSPATIALE PSNL SAID THIS COULD DECREASE FUEL FLOW TO THE L ENG; AT HI POWER, THE R ENG GOVERNOR WOULD THEN INCREASE ITS FUEL FLOW & EXCEED LIMITS UNLESS PLT COMPENSATED. R FUEL SHUTOFF VALVE WAS FOUND NEAR ITS CLOSED POSITION.

## Aircraft

- Registration: [N57901](https://openairdocs.org/deregistered/N57901-1988-08-11), registration cancelled 1988-08-11, S/N 5103 (OpenAirDocs)
- Reported make and model: AEROSPATIALE AS 355F
- Registry model: [Aerospatiale AS 355 F ECUREUIL](https://openairdocs.org/model/aerospatiale-as-355-f-ecureuil) (registry code 8680806) (OpenAirDocs)
- Category: Helicopter
- Serial number: AS-355F
- Airframe hours: 961
- Engines: ALLISON 250-C20F 420 horsepower turbo shaft
- Damage: Destroyed
- Fire: In-Flight
- Flight: Part 135
- Operator: Craig Huntington, doing business as Helicopter West, Inc.[Ems]
- Registered owner: Rts Helicopter Service Corp.
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, December 6, 1983, 2 hours before
- Departed: NV53, LAS VEGAS, NV
- Destination: NEEDLES, CA
- Flight plan: Company VFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 39; airline transport, flight instructor; instrument ratings: helicopter; medical: class 1, valid medical--no waivers/lim.; seat: right; toxicology performed; flight hours: 5,300 total, 400 in this make and model, 5,200 as pilot in command, 90 in the last 90 days, 30 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 75 statute miles
- Lowest ceiling: 25,000 ft overcast
- Temperature: 48 °F, dew point 18 °F
- Altimeter: 30.00 inHg
- Observed at: LAS

## 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 19831207063309A](https://openairdocs.org/incident/19831207063309A), Dec 7, 1983: Aerosp AS355F, Black Mountain, NV, Destroyed, 2 fatal. Helicopter crashed in mountainous terrain. Unsecured engine cowl door tore off hit throttle causing N2 zero thrust.

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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