LAX03TA043 · Bell 47G-3B-1
Bell 47G-3B-1 · Accident: total loss of engine power (mechanical failure) while maneuvering
From Caliente, NV to Panaca, NV
Event
- NTSB case
- LAX03TA043
- 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
- Unknown
- 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
- N48020
- Operator
- Bureau of Land Managment
- Onboard fatalities
- Unknown
- Route
- From Caliente, NVTo Panaca, NV
- 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 91: General Aviation
- 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
- 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
- Engine assembly, valve, intake › Separation
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The helicopter experienced a loss of engine power and landed hard during an autorotation, severing the tail boom. The number 6 cylinder's intake valve separated, with the valve's head wedged in the intake valve seat bore. Removal of the rocker box cover on that cylinder revealed that the spring retainer was broken into numerous pieces. The piston head showed over 15 impressions consistent in dimension to that of the valve head. After examining the number 6 cylinder, a metallurgist determined that the valve failed in between the intake valve head and the valve stem.
Probable cause
separation of the no. 6 cylinder intake valve head from the valve stem, which resulted in a loss of engine power. The mechanism responsible for the valve failure is unknown.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record LAX03TA043
- Event ID
- 20021204X05560
- Case number
- LAX03TA043
- 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: investigation status, coordinates. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: 96a1fcfa57b4b171349c6f7dca7f833124cfc2ee96c678028196585af4e1a4ef; retrieved 2026-09-22T09:51:07.846Z.