# NTSB NYC90LA122: Bell 47G-3B1, N39268, Becket, MA, May 31, 1990

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: May 31, 1990, 09:45 local (13:45 UTC)
- Place: Becket, MA
- Location: 42.3320° N, 73.0829° W: Placed by OpenAirDocs: center of Becket, MA, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=42.3320&lon=-73.0829&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report December 14, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 36655
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=NYC90LA122
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/36655/pdf
- Page: https://openairdocs.org/ntsb/NYC90LA122

## Probable cause

A POWER LOSS DUE TO OIL STARVATION, AFTER MAINTENANCE PERSONNEL FAILED TO COMPLY WITH LYCOMING DIRECTIVES DURING THE ENGINE OVERHAUL. FACTORS RELATED TO THE ACCIDENT WERE: IMPROPER ADJUSTMENT OF THE ENGINE OIL PRESSURE BY MAINTENANCE PERSONNEL AND UNSUITABLE TERRAIN.

## Sequence of events

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

- Loss of engine power(total) - mech failure/malf, cruise - normal
  - maintenance,overhaul,major - improper, other maintenance personnel (cause)
  - maintenance,adjustment - improper, other maintenance personnel (cause)
  - lubricating system,oil port/passage,internal - blocked(total) (cause)
  - engine assembly,connecting rod - failure,total (cause)
- Forced landing, descent - emergency
- In flight collision with terrain/water, landing - flare/touchdown
  - terrain condition - rough/uneven (contributing factor)

## Analysis

THE HELICOPTER ENGINE LOST POWER AND THE PILOT AUTOROTATED INTO UNSUITABLE TERRAIN. THE CAUSE OF THE POWER LOSS WAS A OIL CHANNEL WHICH WAS BLOCKED WITH DEBRIS AND LED TO THE FAILURE OF THE NUMBER 4 BEARING AND CONNECTING ROD. THE ENGINE HAD BEEN OVERHAULED 6 YEARS AND 228.5 HOURS PRIOR TO THE ACCIDENT. LYCOMING SAID THEIR POST CRASH EXAMINATION OF THE ENGINE SHOWED THE OVERHAUL HAD NOT BEEN CONDUCTED IN ACCORDANCE WITH THEIR DIRECTIVES.

## Aircraft

- Registration: [N39268](https://openairdocs.org/deregistered/N39268-2013-07-09), registration cancelled 2013-07-09, S/N 2957, built 1965 (OpenAirDocs)
- Reported make and model: BELL 47G-3B1
- Registry model: [Bell 47G-3B-1](https://openairdocs.org/model/bell-47g-3b-1) (registry code 1181028) (OpenAirDocs)
- Registry engine: [Lycoming VO-435 series](https://openairdocs.org/engine/lycoming-vo-435-series) (registry code 41525, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Serial number: 2957
- Airframe hours: 5720
- Engines: LYCOMING VO-435-A1 240 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Thomas M. Mazzeo
- Registered owner: Thomas Mazzeo
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, May 15, 1990, 11 hours before
- Departed: PSF, PITTSFIELD, MA
- Destination: BAF, WESTFIELD, MA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 49; private; medical: class 3, valid medical--w/ waivers/lim; seat: left; flight hours: 245 total, 186 in this make and model, 81 as pilot in command, 43 in the last 90 days, 15 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 310° at 18 knots
- Visibility: 7 statute miles
- Temperature: 55 °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 19900531018229A](https://openairdocs.org/incident/19900531018229A), May 31, 1990: Bell 47G3B1, Becket, MA, Substantial damage. Lost power,autorotated to rough terrain. Sludge in oil starved rod bearings broke rods. Engine had improper overhaul

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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