# NTSB DEN87FA018: Bell 206L-3, N3889S, Billings, MT, November 7, 1986

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Field investigation · Final report
- Date: November 7, 1986, 08:20 local (15:20 UTC)
- Place: Billings, MT
- Coordinates: 45.760971, -108.569938 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=45.7610&lon=-108.5699&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 2 serious, 1 minor
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 17082
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN87FA018
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/17082/pdf
- Page: https://openairdocs.org/ntsb/DEN87FA018

## Sequence of events

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

- Airframe/component/system failure/malfunction, climb
  - misc eqpt/furnishings - other (cause)
  - aircraft preflight - not performed, pilot in command (cause)
  - pressure induced by others, pilot in command (cause)
  - weather condition - snow
  - weather condition - low ceiling
  - weather condition - fog
- Loss of control - in flight, climb
- In flight collision with terrain/water, descent - uncontrolled
  - terrain condition - none suitable (contributing factor)
  - terrain condition - high obstruction(s) (contributing factor)

## Analysis

WHILE ON TAKEOFF FROM A HOSPITAL ROOF TOP HELIPAD ON AN EMERGENCY MEDICAL SERVICE FLT, A SYNCHRONIZED ELEVATOR COVER BLEW OFF AND STRUCK THE TAIL ROTOR. THIS RESULTED IN AN INFLIGHT SEPARATION OF ONE TAIL ROTOR BLADE AND A LOSS OF ANTI-TORQUE CONTROL. THE PLT EXECUTED AN AUTOROTATION IN THE URBAN AREA WITH NO SUITABLE TERRAIN FOR AN EMERGENCY FORCED LANDING.

## Aircraft

- Registration: N3889S (not matched to a registry record)
- Reported make and model: BELL 206L-3
- Category: Helicopter
- Serial number: 45576
- Airframe hours: 2869
- Engines: ALLISON 250-C30 650 horsepower turbo shaft
- Damage: Destroyed
- Flight: Part 135
- Registered owner: Rocky Mountain Helicopter Inc.
- Airworthiness certificate: Standard, Normal
- Last inspection: AAIP, November 4, 1986, 1 hours before
- Departed: BILLINGS, MT

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 36; airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: helicopter, airplane; medical: class 2, valid medical--no waivers/lim.; seat: right; flight hours: 7,000 total, 1,350 in this make and model, 6,730 as pilot in command, 73 in the last 90 days

## Weather

- Conditions: Instrument (IMC), Day
- Wind: 40° at 7 knots
- Lowest ceiling: 100 ft overcast
- Temperature: 28 °F, dew point 28 °F
- Altimeter: 29.00 inHg
- Observed at: BIL, 1 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 19861107054299A](https://openairdocs.org/incident/19861107054299A), Nov 7, 1986: Bell 206L3, Billings, MT, Destroyed. The helicopter lost the tail rotor after striking a protective cover. Pilot failed to remove cover on preflight.

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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