# NTSB ATL82DA100: S.N.I.A.S. AS350D Astar, N3605B, Alcoa, TN, April 12, 1982

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Final report
- Date: April 12, 1982
- Place: Alcoa, TN
- Coordinates: 35.789009, -83.97039 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=35.7890&lon=-83.9704&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor, 2 uninjured
- Status: Completed, report April 12, 1983
- Report: Approved by Office Director
- Safety recommendations: Yes
- NTSB case key (mKey): 69732
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ATL82DA100
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/69732/pdf
- Page: https://openairdocs.org/ntsb/ATL82DA100

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Airframe/component/system failure/malfunction, approach
  - rotor drive system,tail rotor drive shaft bearing - binding(mechanical) (cause)
  - rotor drive system,tail rotor drive shaft - failure,total (cause)
- Hard landing, landing - flare/touchdown
  - run on landing - performed, pilot in command

## Analysis

WHILE PREPARING TO LAND, THE PILOT EXPERIENCED A TAIL ROTOR DRIVE FAILURE AT A SPEED OF LESS THAN 60 KNOTS. AT THAT SPEED, HE WAS UNABLE TO MAKE THE NECESSARY RIGHT TURN FROM HIS POSITION TO LAND ON THE RUNWAY. INSTEAD, HE CLIMBED ABOUT 50 FT IN A LEFT TURN TO LINE-UP FOR A RUN-ON LANDING. AS HE SLOWED TO ABOUT 20 KNOTS AT LOW ALTITUDE, THE HELICOPTER BEGAN TO YAW HARD TO THE LEFT. THE COLLECTIVE WAS LOWERED TO TOUCHDOWN BEFORE CONTROL WAS LOST. DURING THE LANDING, THE HELICOPTER BOUNCED AND ROTATED ABOUT 90 DEGREES BEFORE COMING TO REST. AN EXAMINATION REVEALED THAT THE NUMBER 4 TAIL ROTOR DRIVE SHAFT BEARING, PN 6007-2RS1MT47CA, HAD SEIZED. THE TAIL ROTOR DRIVE SHAFT AND RUBBER MOUNTING COLLAR CONTINUED TURNING UNTIL THE SEIZED BEARING CHAFFED THROUGH THE COLLAR AND ALSO THE DRIVE SHAFT ITSELF. SUBSEQUENTLY, THE TAIL ROTOR DRIVE SHAFT, PN 350A34-0110-02, SHEARED. THE TAIL ROTOR DRIVE SHAFT BEARING WAS FACTORY LUBED AND SEALED AND HAD NO RETIREMENT TIME LIMIT. THE BEARING FAILED AFTER 729 HOURS OF OPERATION.

## Aircraft

- Registration: [N3605B](https://openairdocs.org/deregistered/N3605B-1989-05-23), registration cancelled 1989-05-23, S/N 1215 (OpenAirDocs)
- Reported make and model: S.N.I.A.S. AS350D ASTAR (AS350D AST)
- Registry model: [S N I A S AS350D ASTAR](https://openairdocs.org/model/s-n-i-a-s-as350d-astar) (registry code 8680803) (OpenAirDocs)
- Category: Helicopter
- Serial number: 1215
- Airframe hours: 729
- Engines: LYCOMING LTS101-600A-2 615 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Executive/Corporate, Part 91
- Operator: Mountain Coals Inc.
- Registered owner: Mountain Coals Inc.
- Departed: MIDDESBORO, KY
- Destination: ALCOA, TN
- Airport: TYS, Mcghee Tyson, runway 22, 6,000 × 150 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 41; commercial, airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; flight hours: 4,615 total, 700 in this make and model, 4,510 as pilot in command, 176 in the last 90 days, 2 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 210° at 13 knots
- Visibility: 15 statute miles
- Lowest ceiling: 30,000 ft broken
- Temperature: 149 °F
- Altimeter: 30.00 inHg
- Observed at: TYS

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19820412009189A](https://openairdocs.org/incident/19820412009189A), Apr 12, 1982: Snias AS350D, Alcoa, TN, Substantial damage. Tail rotor drive failure on landing approach. Lost directional control. Made hard landing. Driveshaft bearing failed

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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