LAX01LA243 · Bell 206B
Bell 206B · Accident: total loss of engine power (mechanical failure) en route
From San Francisco International Airport (SFO) to San Francisco International Airport (SFO)
Event
- NTSB case
- LAX01LA243
- 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 206B
- Aircraft type
- Bell 206
- 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
- N474SF
- Operator
- Mcclelland, John and Teri
- Onboard fatalities
- Unknown
- Route
- From San Francisco International Airport (SFO), San Francisco, CATo San Francisco International Airport (SFO), San Francisco, CA
- 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
- En route · cruise
- 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
- Accessory drive assembly › Fractured
- Accessory drive assembly, drive bearing › Fatigue
- Pilot in command › Directional control, not maintained
- Pilot in command › Flare, inadequate
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The helicopter made a hard landing and severed the tail boom after an in-flight engine failure and autorotation. The pilot reported seeing an engine chip light and hearing a whining sound in the engine about 700 feet agl. An engine out light followed by a complete engine failure occurred about 1 minute later. The pilot had been descending to land in an open field by that time. The collective was lowered to enter an autorotation and aft cyclic applied to slow the forward airspeed. As he neared the bottom of the maneuver, he pulled collective pitch to cushion the landing; however, the helicopter abruptly spun 90 degrees to the left. The main rotor blades struck the tail boom and the ground. The tail boom was separated from the helicopter. After an inspection and teardown of the engine, the 2 1/2 bearing was found to have failed in fatigue. Records revealed that a chip light had been reported in the same helicopter on a flight (4) days prior. Before being returned to service, a magnetic plug inspection/cleaning and an engine ground test run were performed. According to the Allision 250 Series Operation and Maintenance Manual, when either a chip light is encountered after a gearbox flush and a second ground test run has been performed or when a total of (4) chip lights have been encountered within 50 hours of engine operation, the engine must be removed from service and sent to the manufacturer's authorized maintenance center.
Probable cause
The failure of the accessory gearbox 2 1/2 bearing in fatigue resulting in the complete loss of engine power and a subsequent forced landing. The pilot's failure to maintain directional control during the autorotational flare maneuver is also causal. The operator's failure to comply with the recommendations in the engine service manual regarding removal of the engine from service for detailed inspection is a factor.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record LAX01LA243
- Event ID
- 20010713X01426
- Case number
- LAX01LA243
- 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. 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: 32af39718afd3a0157e1403a14e39c2d8521b8328483420a6db78799fe2bb093; retrieved 2026-09-22T11:46:39.834Z.