ERA21LA339 · Enstrom 280 C
Enstrom 280 C · Accident: system/component malfunction/failure (non-power) on approach
Event
- NTSB case
- ERA21LA339
- 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
- Event fatalities
- Unknown
- 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
Enstrom 280 C
- Aircraft type
- Enstrom 280
- 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
- N9285
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From not recordedTo not recorded
- Aircraft age
- About 43 years (built 1978)
- 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
- Approach · VFR pattern final
- 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
- System/component malfunction/failure (non-power)
- 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
- Aircraft › Aircraft propeller/rotor
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot was conducting a local flight when just prior to touchdown, the helicopter began to spin to the right and made an uncommanded climb and spin to the right. The pilot applied full left rudder pedal, but the helicopter continued to spin to the right. He lowered the collective and landed hard on the skids, which resulted in substantial damage to the fuselage. Postaccident examination of the helicopter revealed the tail rotor driveshaft was separated and free to spin inside the coupling. Metallurgical examination of the driveshaft revealed the bolt holes in the driveshaft were distorted, consistent with torsional shear-stress in the clockwise direction.
Probable cause
The failure of the tail rotor drive shaft at the coupling due to torsionally applied shear stress.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record ERA21LA339
- Event ID
- 20210826103759
- Case number
- ERA21LA339
- 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, cause areas. 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: d223f029a2ba1c90ed331cb93e5255dde03bb8e3d14300b76c5e8990251563b5; retrieved 2026-09-16T14:27:34.725Z.