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NTSB Report
May 31, 1990 · Bell 47G-3B1 · N39268
Becket, MA
Overview
Report Status
Probable Cause
Event Type
Accident
Date
May 31, 1990
Injury Outcomes
No injuries (1 uninjured)
Location
Becket, MA
Aircraft
Bell 47G-3B1
Tail Number
N39268
Operator
Thomas M Mazzeo
Injuries
None
Aircraft Damage
Substantial
NTSB Number
NYC90LA122
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.
NTSB 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.
Full Narrative
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.
Flight
Event TypeAccident
Event Time09:45 EDT
Nearest Airport0nm N
Runway0
Runway Length0
Runway Width0
Flight Plan FiledNone
Aircraft FireNo
Aircraft ExplosionNo
Aircraft
AircraftBell 47G-3B1
Tail NumberN39268
Aircraft CategoryHeli
DamageSubstantial
OperatorThomas M Mazzeo
Operating RulePart 91
Engines1
Engine TypeReciprocating
Engine DetailsLycoming · VO-435-A1 · Reciprocating · 240
Seats3
People & Injuries
Injury SummaryNo injuries (1 uninjured)
Fatal0
Serious0
Minor0
Uninjured1
Total1
Crew 1Age 49 · Third Class
Conditions
ConditionsVMC
LightDaylight
Wind310° @ 18 kt
Visibility7 sm
CeilingNone
Temperature / Dew Point55 / 0 C
Altimeter0
Weather SourcePILO