# NTSB MIA92LA014: Bell 47G-5, N1201W, La Belle, FL, October 13, 1991

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: October 13, 1991, 08:25 local (12:25 UTC)
- Place: La Belle, FL
- Coordinates: 26.639184, -81.340873 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=26.6392&lon=-81.3409&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report May 27, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 33021
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MIA92LA014
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/33021/pdf
- Page: https://openairdocs.org/ntsb/MIA92LA014

## Probable cause

THE PILOT IN COMMAND'S IMPROPER AFT APPLICATION OF CYCLIC CONTROL DURING AN AUTOROTATIVE LANDING TO AN OPEN FIELD, RESULTING IN THE MAIN ROTOR BLADES COLLIDING WITH THE TAIL BOOM.  CONTRIBUTING TO THE ACCIDENT WAS THE IN FLIGHT FAILURE OF THE OUTER BEARING OF THE LOWER GEARCASE INPUT QUILL ASSEMBLY.

## Sequence of events

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

- Airframe/component/system failure/malfunction, cruise
  - rotor drive system,engine to transmission drive - failure,total (contributing factor)
- Forced landing, descent - emergency
- Abrupt maneuver, landing - flare/touchdown
  - flight controls - improper use of, pilot in command (cause)

## Analysis

THE PILOT WAS IN CRUISE FLIGHT AT 200 FEET AGL WHEN HE HEARD A LOUD BANG AND A ROARING NOISE.  THE PILOT CONDUCTED AN AUTOROTATION TO AN OPEN FIELD.  THE HELICOPTER TOUCHED DOWN IN A TAIL LOW ATTITUDE, NOSED OVER AND SLID FORWARD.  THE PILOT STATED, 'I PULLED A LITTLE TOO MUCH AFT CYCLIC AND THE MAIN ROTOR BLADES COLLIDED WITH THE TAIL BOOM. INVESTIGATION OF THE AIRFRAME SYSTEM FAILURE REVEALED THE OUTER BEARING OF THE LOWER GEARCASE INPUT QUILL ASSEMBLY FAILED FOR UNDETERMINED REASONS.

## Aircraft

- Registration: [N1201W](https://openairdocs.org/aircraft/N1201W), registered now, S/N 7819, built 1966 (OpenAirDocs)
- Reported make and model: BELL 47G-5
- Registry model: [Bell 47G-5](https://openairdocs.org/model/bell-47g-5) (registry code 1181032) (OpenAirDocs)
- Registry engine: [Allison 250 series](https://openairdocs.org/engine/allison-250-series) (registry code 03014, turbo-prop) (OpenAirDocs)
- Category: Helicopter
- Serial number: 7819
- Engines: ALLISON 250-C20B 420 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Part 137
- Operator: Colony Services, Inc.
- Registered owner: Colony Services, Inc.

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 50; airline transport, flight instructor, commercial; airplane ratings: multi-engine land, single-engine sea, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; flight hours: 7,000 total, 60 in this make and model, 6,500 as pilot in command

## Weather

- Conditions: Visual (VMC), Day
- Wind: 90° at 8 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: -0 °F, dew point -0 °F

## 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 19911013046479A](https://openairdocs.org/incident/19911013046479A), Oct 13, 1991: Bell 47G5, Labelle, FL, Substantial damage. En route to spray, loud noise and roaring sound. Autorotated but too much cyclic. Chopped boom. Quill assembly failed

## Other investigations on N1201W (2)

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 MIA84LA179](https://openairdocs.org/ntsb/MIA84LA179), Jun 7, 1984: Bell 47G-5 (N1201W), Jupiter, FL, substantial damage
- [NTSB DIA69F0110](https://openairdocs.org/ntsb/DIA69F0110), Nov 22, 1968: Bell 47G-5 (N1201W), Roanoke, VA, substantial damage

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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