CEN09LA198 · Bell 206 L4
Rotorcraft Leasing Bell 206 L4 · Accident: flight control system malfunction/failure while standing
From South Lafourche Leonard Miller Jr Airport (GAO) to South Lafourche Leonard Miller Jr Airport (GAO)
Event
- NTSB case
- CEN09LA198
- 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 206 L4
- 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
- N410RL
- Operator
- Rotorcraft Leasing
- Onboard fatalities
- Unknown
- Route
- From South Lafourche Leonard Miller Jr Airport (GAO), Galliano, LATo South Lafourche Leonard Miller Jr Airport (GAO), Galliano, LA
- 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
- Standing · engine(s) operating
- Defining eventThe 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
- Flight control system malfunction/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
- Personnel issues › Action/decision
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The commercial pilot was starting the single-engine helicopter's engine when he heard a loud bang and vibration. He immediately shut down the engine and exited the helicopter. Examination of the helicopter revealed that the tail rotor driveshaft and coupling had severed just forward of the gearbox, which resulted in substantial damage to the tail boom. The helicopter had undergone recent maintenance to the tail rotor gearbox input seal which included the removal of the tail rotor drive shaft from the coupling. When the two components were reattached, the mechanic only hand-tightened the bolts, figuring additional maintenance was still planned for the gearbox. He then installed the tail rotor drive shaft shaft cover. The mechanic moved on to another project and did not make a logbook entry of the work that he had completed or that the bolts were only hand-tightened. Another mechanic later performed additional maintenance to the gearbox, but the bolts were not checked since the maintenance manual did not require the removal of the tail rotor driveshaft cover. A .2-hour maintenance flight check was conducted and the helicopter was returned to service. The accident occurred on first engine start after it had been returned to service.
Probable cause
The failure of the tail rotor driveshaft and coupling during engine start due to the mechanic's failure to properly reattach the tail rotor driveshaft and coupling during maintenance.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN09LA198
- Event ID
- 20090310X83102
- Case number
- CEN09LA198
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
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: d5b8829352569ab80d029166ee9d0ee286559bf94caea7bf8753a056322b4e81; retrieved 2026-09-15T10:49:35.888Z.