# NTSB DEN84LA036: Bell 205A-1, N1084N, Cokeville, WY, December 2, 1983

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: December 2, 1983, 10:45 local (17:45 UTC)
- Place: Cokeville, WY
- Coordinates: 42.079574, -110.950119 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=42.0796&lon=-110.9501&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 16299
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN84LA036
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/16299/pdf
- Page: https://openairdocs.org/ntsb/DEN84LA036

## Sequence of events

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

- In flight encounter with weather, cruise
  - planning/decision - improper, pilot in command (cause)
  - weather condition - low ceiling (contributing factor)
  - weather condition - snow (contributing factor)
  - precautionary landing - initiated, pilot in command
  - terrain condition - snow covered (contributing factor)
  - weather condition - whiteout (contributing factor)
  - vfr flight into imc - inadvertent, pilot in command (cause)
- In flight collision with terrain/water, landing

## Analysis

THE PLT REPORTED THAT SNOW HAD BEEN FALLING REGULARILY FOR THE PREVIOUS FEW DAYS BEFORE THE FLT. HE DEPARTED THE STAGING AREA WITH 12 DRILL CREW MEMBERS. AT THAT TIME, THE VISIBILITY WAS 2 TO 3 MI & A CEILING OF 800 TO 1000 FT. THE PLT FLEW 9 OF THE PASSENGERS TO A SEISMIC LINE ON AN 8000 FT RIDGE LINE, THEN FLEW THE OTHER PASSENGERS TO THE VALLEY FLOOR, WHERE THEIR EQUIPMENT WAS LOCATED. DURING ARRIVAL, THERE WAS A 500 FT CEILING, THE VISIBILITY WAS ABOUT 1 MI & SNOW WAS FALLING LIGHTLY. WHILE LANDING, THE ROTOR WASH KICKED UP CONSIDERABLE SNOW, BUT THE PLT WAS ABLE TO USE THE DRILL RIGS FOR A VISUAL REFERENCE. HE TOOK OFF AGAIN TO RETURN TO THE STAGING AREA, BUT AFTER FLYING APRX 1/4 MI, THE SNOW SHOWER INCREASED & THE VISIBILITY BEGAN DROPPING. HE DECIDED TO LAND & WAIT FOR THE WX TO IMPROVE. HOWEVER, AS HE APPROACHED THE GROUND, ALL VISUAL REFERENCE WAS LOST DUE TO SNOW KICKED UP FROM THE ROTOR WASH. SUBSEQUENTLY, THE HELICOPTER DRIFTED TO THE RIGHT, THE RIGHT SKID DUG INTO THE SNOW & THE HELICOPTER ROLLED OVER.

## Aircraft

- Registration: N1084N (not matched to a registry record)
- Reported make and model: BELL 205A-1
- Category: Helicopter
- Serial number: 30308
- Airframe hours: 2172
- Engines: LYCOMING T5313B 1250 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Part 135
- Registered owner: Heli-Jet Corporation
- Airworthiness certificate: Standard, Normal
- Last inspection: Continuous airworthiness, November 11, 1983, 32 hours before
- Departed: COKEVILLE, WY

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 35; commercial; airplane ratings: single-engine land; instrument ratings: helicopter; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 5,361 total, 5,011 in this make and model, 5,191 as pilot in command, 67 in the last 90 days

## Weather

- Conditions: Instrument (IMC), Day
- Wind: 50° at 5 knots
- Temperature: 28 °F, dew point 28 °F
- Altimeter: 29.00 inHg
- Observed at: EVW, 52 nm away

## 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 19831202059719A](https://openairdocs.org/incident/19831202059719A), Dec 2, 1983: Bell 205A1, Cokeville, WY, Substantial damage. Lost visual reference while landing on a snow covered area. Downwash and snow shower caused whiteout and rollover.

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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