# NTSB LAX93LA050: Bell 206B-III, N789N, Hilo, HI, November 21, 1992

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: November 21, 1992, 11:15 local (21:15 UTC)
- Place: Hilo, HI
- Coordinates: 19.689428, -155.079681 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=19.6894&lon=-155.0797&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 3 minor
- Status: Completed, report September 14, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 27872
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX93LA050
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/27872/pdf
- Page: https://openairdocs.org/ntsb/LAX93LA050

## Probable cause

THE PILOT'S INTENTIONAL FLIGHT IN AND NEAR A VOLCANIC GAS CLOUD WHICH INDUCED A PARTIAL LOSS OF ENGINE POWER DUE TO A LACK OF COMBUSTIBLE OXYGEN IN THE ATMOSPHERE.

## Sequence of events

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

- Loss of engine power(partial) - nonmechanical, maneuvering
  - in-flight planning/decision - improper, pilot in command (cause)
- Forced landing, descent - emergency
- In flight collision with terrain/water, descent - emergency
  - terrain condition - blind/box canyon

## Analysis

THE HELICOPTER WAS EQUIPPED WITH 2 CAMERAS AND WAS DOING FILMING RUNS OF A VOLCANO VENT CRATER AND ITS ASSOCIATED SMOKE PLUME FOR A MOTION PICTURE. THE PILOT SAID THAT ON THE THIRD PASS OVER THE CRATER HE NOTICED THE MAIN ROTOR RPM DECREASING AND SAW THE ROTOR CAUTION LIGHT. HE SAID HE LOWERED THE COLLECTIVE AND INADVERTENTLY ENTERED THE VOLCANO SMOKE AND STEAM CLOUD. AFTER TURNING HE EXITED THE CLOUD AND AUTOROTATED TO THE CRATER BOTTOM. THE MAIN ROTOR STRUCK THE SHEAR ROCK WALL DURING THE FLARE AND SEPARATED FROM THE HELICOPTER. TWO CAMERA OPERATORS ONBOARD SAID THE PILOT ANNOUNCED 'WE'VE GOT A PROBLEM' AS THEY ENTERED THE SMOKE CLOUD. BOTH WITNESSES SAID THEY DID NOT HEAR THE LOW ROTOR WARNING TONE AND PERCEIVED NO CHANGE IN ENGINE SOUND DURING THE EVENT. ONE SAID HE FELT 'SIDEWARD YAWING MOTIONS' DURING THE DESCENT. THE CAMERA OPERATORS SAID THAT AFTER THE HELICOPTER EMERGED FROM THE CLOUD NEAR THE BOTTOM OF THE CRATER THE ROTOR STRUCK THE ROCK WALL.

## Aircraft

- Registration: [N789N](https://openairdocs.org/deregistered/N789N-1993-03-11), registration cancelled 1993-03-11, S/N 1267 (OpenAirDocs)
- Reported make and model: BELL 206B-III
- Registry model: [Bell 206B](https://openairdocs.org/model/bell-206b) (registry code 1181511) (OpenAirDocs)
- Category: Helicopter
- Serial number: 1267
- Airframe hours: 13609
- Engines: ALLISON 250-C20B 420 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Other work use, Part 91
- Operator: Paramount Pictures
- Registered owner: Hilo Bay Air, Inc.
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, December 16, 1992, 10 hours before
- Departed: NONE, HILO, HI

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 35; flight instructor, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: left; toxicology performed; flight hours: 8,762 total, 2,239 in this make and model, 8,509 as pilot in command, 91 in the last 90 days, 26 in the last 30 days, 5 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 90° at 5 knots
- Visibility: 5 statute miles
- Lowest ceiling: 2,000 ft broken
- Altimeter: 30.00 inHg

## 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 19921121047539A](https://openairdocs.org/incident/19921121047539A), Nov 21, 1992: Bell 206B3, Hilo, HI, Substantial damage. Filming movie flew low over volcano vent plume. Lost power. Rotors hit rocks. Engine corroded by sulphur. No STC ops

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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