# NTSB DEN83LA115: Bell 47G-3B-1, N1129W, Montrose, CO, May 20, 1983

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: May 20, 1983, 09:43 local (15:43 UTC)
- Place: Montrose, CO
- Coordinates: 38.489124, -107.870559 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=38.4891&lon=-107.8706&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor, 1 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 16077
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN83LA115
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/16077/pdf
- Page: https://openairdocs.org/ntsb/DEN83LA115

## Sequence of events

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

- In flight encounter with weather, maneuvering
  - weather condition - low ceiling (contributing factor)
  - weather condition - fog (contributing factor)
  - flight into known adverse weather - continued, pilot in command (cause)
- In flight collision with object, maneuvering
  - object - tree(s) (contributing factor)
  - terrain condition - open field (contributing factor)

## Analysis

WX AT THE DEPARTURE POINT WAS VMC BUT THE SURROUNDING MOUNTANS WERE PARTIALLY OBSCURED. THE PLT STATED THAT HE WAS FOLLOWING A ROAD UP THE MOUNTAIN & LANDED AS THE VISIBILITY DETERIORATED. EACH TIME THE CLOUD LIFTED THE PLT WOULD LIFT-OFF & AGAIN LAND AS THE VISIBILITY DETERIORATED. DURING THE 5TH TRIP UP THE ROAD, VISIBILITY WAS ABOUT 1/2 MI. THE PLT STATED THE 1ST SWITCHBACK WAS '...NOT LANDABLE, BUT THE SECOND ONE APPEARED TO BE.' ABOUT 1/2 WAY TO THE SECOND SWITCHBACK THE CEILING '...PLUMMETED DOWN. THE ROAD CLOSED IN BEHIND ME AND I STARTED LOOSING THE NEXT SWITCHBACK.' OAK BRUSH TREES ON THE HILLSIDE BORE EVIDENCE OF BEING CUT & BROKEN NEXT TO THE WRECKAGE.

## Aircraft

- Registration: N1129W (not matched to a registry record)
- Reported make and model: BELL 47G-3B-1
- Category: Helicopter
- Serial number: 1181028
- Airframe hours: 9429
- Engines: ALLISON 250-C20-B 400 horsepower turbo shaft
- Damage: Destroyed
- Fire: On-Ground
- Flight: Part 135
- Registered owner: Thunderbird Helicopters, Inc.
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, March 1, 1983, 55 hours before
- Departed: MONTROSE, CO
- Destination: STORM KING MTN, CO
- Flight plan: Company VFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 35; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 5,874 total, 342 in this make and model, 5,656 as pilot in command, 52 in the last 90 days

## Weather

- Conditions: Instrument (IMC), Day
- Wind: calm
- Visibility: 5 statute miles
- Lowest ceiling: 100 ft overcast
- Temperature: 37 °F

## 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 19830520020619A](https://openairdocs.org/incident/19830520020619A), May 20, 1983: Bell 47G3B1, Montrose, CO, Destroyed. Pilot flew into weather attempting to continue up mountain slope. Blade struck ground and helicopter disintegrated.

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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