# NTSB NYC90DNA04: Bell 47G-3B-1, N34691, Hanson, MA, August 1, 1990

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Final report
- Date: August 1, 1990, 07:30 local (11:30 UTC)
- Place: Hanson, MA
- Location: 42.0650° N, 70.8498° W: Placed by OpenAirDocs: center of Hanson, MA, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=42.0650&lon=-70.8498&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report December 14, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 36505
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=NYC90DNA04
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/36505/pdf
- Page: https://openairdocs.org/ntsb/NYC90DNA04

## Probable cause

THE PILOT'S LOSS OF CONTROL OF THE HELICOPTER DUE TO THE FAILURE OF THE TAIL ROTOR DRIVE SHAFT.

## Sequence of events

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

- Airframe/component/system failure/malfunction, maneuvering - aerial application
  - rotor drive system,tail rotor drive shaft - failure,total (cause)
- Hard landing, descent - uncontrolled
  - terrain condition - grass

## Analysis

THE PILOT STATED THAT WHILE HE WAS OPERATING THE HELICOPTER AT 100 FEET ABOVE THE GROUND IN AERIAL APPLICATION ACTIVITIES, THERE WAS A LOSS OF TAIL ROTOR CONTROL. THE HELICOPTER ENTERED A 'SLOW SPIN' AND DESCENDED INTO THE GROUND. POST-ACCIDENT INVESTIGATION REVEALED THAT THE TAIL ROTOR DRIVE SHAFT WAS 'SHEARED OFF' BETWEEN THE NUMBER 5 AND NUMBER 6 BEARINGS.

## Aircraft

- Registration: [N34691](https://openairdocs.org/deregistered/N34691-1993-07-14), registration cancelled 1993-07-14, S/N 3822 (OpenAirDocs)
- Reported make and model: BELL 47G-3B-1
- Registry model: [Bell 47G-3B-1](https://openairdocs.org/model/bell-47g-3b-1) (registry code 1181028) (OpenAirDocs)
- Category: Helicopter
- Serial number: 3822
- Airframe hours: 5306
- Engines: LYCOMING TV0-435-B1A 260 horsepower reciprocating
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Registered owner: Ashley Cranberry Enterprise
- Airworthiness certificate: Special, Restricted (Special); Standard, Normal
- Last inspection: 100 hour, July 14, 1990, 11 hours before
- Departed: NONE, WAREHAM, MA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 32; commercial, flight instructor; airplane ratings: single-engine land, multi-engine land; instrument ratings: helicopter, airplane; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 4,100 total, 2,000 in this make and model, 3,700 as pilot in command, 150 in the last 90 days, 100 in the last 30 days, 4 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 350° at 3 knots
- Lowest ceiling: none
- Temperature: 72 °F
- Altimeter: 30.00 inHg

## 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 19900801029489A](https://openairdocs.org/incident/19900801029489A), Aug 1, 1990: Bell 47G3B1, Hanson, MA, Substantial damage. Tail rotor drive shaft sheared during spray run,autorotated too hard landing in cranberry bog.

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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