# NTSB LAX86DVA13: Bell 47G-4A, N1185W, Shafter, CA, August 8, 1986

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Final report
- Date: August 8, 1986, 08:15 local (15:15 UTC)
- Place: Shafter, CA
- Coordinates: 35.489562, -119.299324 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=35.4896&lon=-119.2993&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 24867
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX86DVA13
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/24867/pdf
- Page: https://openairdocs.org/ntsb/LAX86DVA13

## Sequence of events

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

- Airframe/component/system failure/malfunction, takeoff - initial climb
  - rotor drive system,tail rotor drive shaft bearing - failure,total (cause)
  - rotor drive system,tail rotor drive shaft bearing - overtemperature (cause)
  - maintenance,lubrication - not performed, company maintenance personnel (cause)
  - maintenance,100-hour inspection - not performed, company maintenance personnel (cause)
- Forced landing, descent - emergency
  - autorotation - attempted, pilot in command
- In flight collision with terrain/water, descent - emergency
  - terrain condition - rough/uneven

## Analysis

SHORTLY AFTER DEPARTING THE LOADING RIG, EN ROUTE TO AN AGRICULTURAL AERIAL APPLICATION OPERATION, THE FORWARD COUPLING TAIL ROTOR DRIVE SHAFT FAILED. THE HELICOPTER WAS ABOUT 10 FT ABOVE GROUND LEVEL AND ABOUT 100 FT WEST OF THE LOADING RIG. THE PILOT ATTEMPTED AN IMMEDIATE AUTOROTATION BUT COLLIDED WITH THE GROUND AND ROLLED OVER. EXAMINATION OF THE WRECKAGE DISCLOSED THE COUPLING SUSTAINED EXTREME HIGH TEMP DISTRESS DUE TO LACK OF LUBRICATION. THE HELICOPTER HAD FLOWN 178 HOURS SINCE THE LAST ANNUAL/100-HOUR INSPECTION. A 100-HOUR INSPECTION IS REQUIRED FOR THE OPERATION.

## Aircraft

- Registration: [N1185W](https://openairdocs.org/deregistered/N1185W-2018-04-25), registration cancelled 2018-04-25, S/N 7513, built 1966 (OpenAirDocs)
- Reported make and model: BELL 47G-4A
- Registry model: [Bell 47G-4A](https://openairdocs.org/model/bell-47g-4a) (registry code 1181031) (OpenAirDocs)
- Registry engine: [Lycoming VO-540 series](https://openairdocs.org/engine/lycoming-vo-540-series) (registry code 41534, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Serial number: 7513
- Airframe hours: 7723
- Engines: LYCOMING VO-540 305 horsepower reciprocating
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Registered owner: Shafter Aviation Inc.
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: 100 hour, June 21, 1986, 178 hours before
- Airport: MIT, Shafter-Minter Field

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 40; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: right; flight hours: 2,438 total, 1,438 in this make and model, 2,438 as pilot in command, 7 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 130° at 5 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 79 °F, dew point 55 °F
- Altimeter: 31.00 inHg
- Observed at: BFL, 6 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 (OpenAirDocs).

- [Accident 19860808038149A](https://openairdocs.org/incident/19860808038149A), Aug 8, 1986: Bell 47G4A, Shafter, CA, Substantial damage. The helicopter struck the ground during takeoff after loss of directional control. Tailrotor drive shaft failed.

## Other investigations on N1185W (1)

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.

- [NTSB LAX93LA120](https://openairdocs.org/ntsb/LAX93LA120), Feb 13, 1993: Bell 47G (N1185W), Bakersfield, CA, substantial damage. Probable cause: THE CLUTCH SLIPPAGE AND FAILURE OF THE PILOT TO JETTISON THE LOAD.

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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