ATL91FA013 · Bell 47J-2
Pigeon Forge Helicopters Bell 47J-2 · Accident: airframe, component or system failure en route
From Pigeon Forge, TN (no airport) to an unrecorded destination
Event
- NTSB case
- ATL91FA013
- 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 47J-2
- 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
- N49DA
- Operator
- Pigeon Forge Helicopters
- Onboard fatalities
- Unknown
- Route
- From Pigeon Forge, TN (no airport)To 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 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
- Airframe, component or system failure
- Also codedOther events the NTSB coded in the sequence, such as a wire strike after a loss of power. Flight Findings uses them for its kinds of event. Glossary
- Tree(s)
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Destroyed
Cause areas
- Company maintenance personnel › Maintenance, inspection, inadequate
- Rotor drive system, tail rotor drive shaft bearing › Worn
- Rotor drive system, tail rotor drive shaft › Fatigue
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
THE TWO PASSENGERS REPORTED THAT THEY HEARD A 'POP' SOUND, FOLLOWED BY THE HELICOPTER STARTING A CLOCKWISE SPIN TO THE RIGHT. THE HELICOPTER DESCENDED INTO THE TREES ON THE SIDE OF A STEEP SLOPE. INVESTIGATION REVEALED THAT THE TAIL ROTOR DRIVE SHAFT FAILED IMMEDIATELY FORWARD OF THE TAILBOOM EXTENSION TUBE. THE DRIVE SHAFT FAILED FROM FATIGUE CRACKING, PROPAGATING AT A HIGH RATE, SUGGESTING HIGH LOADS. THE T/R DRIVE SHAFT FORWARD BEARING HOUSING OUTER DIAMETER DIMENSION AND THE INNER DIAMETER OF THE TAILBOOM EXTENSION TUBE WERE WORN BEYOND REPLACEMENT LIMITS AND SHOULD HAVE BEEN REPLACED ACCORDING TO THE BELL MAINTENANCE AND OVERHAUL MANUAL. THE PASSENGER THREE-PLACE BENCH SEAT HAD BEEN ALTERED SO THAT THE INDIVIDUAL SEAT BELTS HAD BEEN MODIFIED INTO ONE SINGLE LONG BELT. THE BELT COULD BE OPENED ONLY ON THE LEFT SIDE OF THE BELT; THE BUCKLE ON THE RIGHT SIDE OF THE BELT WAS TAPED CLOSED WITH SILVER DUCT TAPE.
Probable cause
THE ACCIDENT WAS INADEQUATE MAINTENANCE OF THE HELICOPTER, ALLOWING A TAIL ROTOR DRIVE SHAFT BEARING TO EXCEED WEAR LIMITS. THIS RESULTED IN HIGH LOADS ON THE TAIL ROTOR DRIVE SHAFT, AND THE RESULTING FATIGUE FAILURE OF THE DRIVE SHAFT.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record ATL91FA013
- Event ID
- 20001212X24558
- Case number
- ATL91FA013
- 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: 3cb21028004dcc8c48d08f5bc696aab880e07db596648304d294fe96a9a7fca1; retrieved 2026-09-21T15:33:53.825Z.