# NTSB LAX92LA041: Bell 206B, N16712, Hilo, HI, November 9, 1991

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: November 9, 1991, 10:45 local (20:45 UTC)
- Place: Hilo, HI
- Coordinates: 19.689947, -155.07936 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=19.6899&lon=-155.0794&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 1 serious, 2 minor, 2 uninjured
- Status: Completed, report April 27, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 27500
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX92LA041
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/27500/pdf
- Page: https://openairdocs.org/ntsb/LAX92LA041

## Probable cause

THE INADVERTENT ENCOUNTER WITH A LOSS OF TAIL ROTOR EFFECTIVENESS PHENOMENA AND THE RESULTANT PILOT INFLIGHT LOSS OF CONTROL.

## Sequence of events

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

- Loss of control - in flight, maneuvering - turn to reverse direction
  - aircraft performance,yawing maneuvers - exceeded
  - compensation for wind conditions - inadequate, pilot in command (cause)
  - directional control - not maintained, pilot in command (cause)
- In flight collision with terrain/water, descent - emergency
  - descent - intentional, pilot in command

## Analysis

ACCORDING TO THE PILOTS STATEMENT, AS THE HELICOPTER FLEW OVER A SADDLE PASS IN A MOUNTAIN AREA THE FLIGHT ENCOUNTERED CLOUDS WHICH RAPIDLY CLOSED DOWN ON AND AROUND THE AIRCRAFT. THE PILOT SAID 'I HAD NO CHOICE BUT TO SLOW DOWN AND TRY TO TURN AROUND WITHOUT GETTING INTO THE LOW CLOUDS THAT WERE MOVING IN.' AS THE AIRCRAFT SLOWED, IT SUDDENLY BEGAN TO ROTATE TO THE RIGHT. THE PILOT WAS UNABLE TO CORRECT THE YAW WITH LEFT PEDDLE INPUT AND AFTER THREE REVOLUTIONS THE LOW ROTOR RPM HORN SOUNDED. THE PILOT SAID THAT SHE FELT THE HELICOPTER CONTROL DIMINISH AND SHE ELECTED TO PUT THE HELICOPTER DOWN ON THE GROUND. AT AN ALTITUDE OF ABOUT 6 FEET THE PILOT LOWERED THE COLLECTIVE AND THE HELICOPTER LANDED HARD IN A LEVEL ATTITUDE.

## Aircraft

- Registration: [N16712](https://openairdocs.org/deregistered/N16712-2012-07-19), registration cancelled 2012-07-19, S/N 2181 (OpenAirDocs)
- Reported make and model: BELL 206B
- Registry model: [Bell 206B](https://openairdocs.org/model/bell-206b) (registry code 1181511) (OpenAirDocs)
- Category: Helicopter
- Serial number: 2181
- Airframe hours: 13499
- Engines: ALLISON 250-C20 420 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Part 135
- Operator: Kona Helicopters
- Registered owner: Kona Helicopters
- Airworthiness certificate: Standard, Normal
- Last inspection: AAIP, October 23, 1991, 58 hours before
- Departed: HI07, WAIKOLOA, HI
- Destination: ITO, HILO, HI
- Flight plan: Company VFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 30; flight instructor, commercial; medical: class 2, valid medical--no waivers/lim.; seat: right; flight hours: 1,600 total, 1,530 as pilot in command, 220 in the last 90 days, 55 in the last 30 days, 5 in the last 24 hours

## Weather

- Conditions: Instrument (IMC), Day
- Lowest ceiling: 900 ft broken
- Temperature: 61 °F, dew point -0 °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 19911109050069A](https://openairdocs.org/incident/19911109050069A), Nov 9, 1991: Bell 206B, Hilo, HI, Substantial damage. Encountered low clouds and rain. Slowed to turn around. Lost tail rotor control. RPM decay and hard landing ensued.

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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