- Date
- November 1, 1990, 14:00 local (19:00 UTC)
- Place
- Gatlinburg, TN
- Injuries
- 1 serious, 2 minor
- Damage
- Destroyed
- Phase of flight
- Enroute
- Aircraft
- N49DABell 47J-2
- Weather
- Visual (VMC) · Day
- Status
- Completed · report December 14, 1992
- Report
- Approved by Office Director
- FAA report
- 19901101048849A
- Case key
- 8296
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
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.
Sequence of events
NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.
Analysis
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.
Aircraft
- Registration
- N49DA
- Reported as
- Bell 47J-2
- Category
- Helicopter
- Serial number
- 1825
- Airframe hours
- 8,972
- Engine
- Lycoming VO-540-B1B3, 260 horsepower, reciprocating
- Damage
- Destroyed
- Flight
- Part 91
- Operator
- Pigeon Forge Helicopters, Inc.
- Registered owner
- Pigeon Forge Helicopters, Inc
- Last inspection
- Annual · October 7, 1990 · 85 hours before
- Departed
- NONE · Pigeon Forge, TN
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 43
- Certificate
- Commercial
- Airplane ratings
- Single-engine land
- Medical
- Class 2, Valid Medical--w/ waivers/lim
- Seat
- Front
- Toxicology
- Performed
- Flight hours
- 8,448 total · 8,370 as pilot in command · 385 in the last 90 days · 120 in the last 30 days · 2 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- Calm
- Visibility
- 15 statute miles
- Lowest ceiling
- None
- Temperature
- 73 °F, dew point 43 °F
- Altimeter
- 30.00 inHg
- Observed at
- TYS, 26 nm away
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.