# NTSB NYC87LA210: Bell 47G3, N6355, Marston Mills, MA, July 24, 1987

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: July 24, 1987, 15:40 local (19:40 UTC)
- Place: Marston Mills, MA
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 2 minor, 1 uninjured
- Status: Completed, report June 16, 1989
- Report: Approved by Office Director
- NTSB case key (mKey): 30700
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=NYC87LA210
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/30700/pdf
- Page: https://openairdocs.org/ntsb/NYC87LA210

## Sequence of events

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

- Loss of engine power, takeoff - initial climb
  - reason for occurrence undetermined (cause)
- Forced landing, descent - emergency
  - autorotation - attempted, pilot in command
  - altitude - inadequate
- Hard landing, landing

## Analysis

THE HELICOPTER REACHED AN ALTITUDE OF ABOUT 50 FEET WHEN A LOSS OF POWER WAS EXPERIENCED. IMMEDIATELY THE PILOT SET UP FOR AN EMERGENCY LANDING AND SET THE HELICOPTER DOWN. THE AIRCRAFT, HOWEVER, COLLIDED WITH THE GROUND HARD AND INCURRED SUBSTANTIAL DAMAGE. CONDITIONS WERE CONDUCIVE TO CARBURETOR ICING DURING GLIDE POWER, NOT TKOF POWER. INVESTIGATION REVEALED THAT FUEL WAS IN THE FUEL TANKS. NO REASON WAS FOUND THAT COULD EXPLAIN THE LOSS OF POWER TO THE ENGINE.

## Aircraft

- Registration: [N6355](https://openairdocs.org/aircraft/N6355), registered now, S/N 1670, built 1956 (OpenAirDocs)
- Reported make and model: BELL 47G3
- Registry model: [Bell 47G](https://openairdocs.org/model/bell-47g) (registry code 1181002) (OpenAirDocs)
- Registry engine: [Franklin 6V 350 series](https://openairdocs.org/engine/franklin-6v-350-series) (registry code 27043, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Serial number: 26079
- Engines: FRANKLIN 6VS-335-A 225 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Cornelius M.Throwbridge,III
- Registered owner: Cornelius M. Trowbridge
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, July 1, 1987, 70 hours before
- Departed: CAPE COD, MA
- Airport: Cape Cod

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 49; flight instructor, commercial; airplane ratings: single-engine land; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 6,510 total, 3,500 in this make and model, 6,500 as pilot in command, 10 in the last 90 days, 2 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Lowest ceiling: none

## 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 19870724044969A](https://openairdocs.org/incident/19870724044969A), Jul 24, 1987: Bell 47G, Marston Mills, MA, Substantial damage. Lost power at 50 ft AGL on vertical takeoff. Landed hard. No reason found for power loss.

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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