LAX94LA200 · Bell 47G-3B-1
Sundown Helicopters Bell 47G-3B-1 · Accident: total loss of engine power (mechanical failure) while maneuvering
Event
- NTSB case
- LAX94LA200
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- 0
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Bell 47G-3B-1
- Aircraft type
- Bell 47
- Category
- Helicopter
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N304JP
- Operator
- Sundown Helicopters
- Onboard fatalities
- Unknown
- Route
- From not recordedTo not recorded
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 137: Agricultural
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Maneuvering · aerial application
- First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Total loss of engine power (mechanical failure)
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Other maintenance personnel › Maintenance, installation, improper
- Throttle/power lever, bellcrank › Separation
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot reported that the helicopter had completed a swath run and was pulling up to clear a line of trees when the engine decelerated to idle. The pilot entered an autorotation and landed hard, damaging the skids and the fuselage. Postaccident inspection of the engine revealed that the throttle arm had come off the carburetor throttle body shaft. The operator stated that the arm and shaft were new components, installed on February 24, 1994, by a contract mechanic. The operator also stated that an 'excessive amount (about 2 inches) of safety wire was on the arm, which allowed the arm to slip off the shaft.'
Probable cause
an uncommanded engine deceleration to idle due to the improper installation of the throttle arm on the carburetor shaft.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record LAX94LA200
- Event ID
- 20001206X01140
- Case number
- LAX94LA200
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: local date, investigation status. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 1994-04-17.
- API snapshot SHA-256: 549698dd9e4dd2c2d2848cc45037cb63b1693945a9dea12073f4386a5ad9bc5b; retrieved 2026-09-23T01:10:11.383Z.