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NTSB Report
December 2, 1988 · Bell 47D1 · N163B
Russell, MA
Overview
Report Status
Probable Cause
Event Type
Accident
Date
December 2, 1988
Injury Outcomes
1 injury (1 fatality)
Location
Russell, MA
Aircraft
Bell 47D1
Tail Number
N163B
Injuries
Fatal
Aircraft Damage
Destroyed
NTSB Number
NYC89DNE01
THE BELL 47D1 WAS ON A SOLO X-COUNTRY FLIGHT WITH A COMMERCIAL RATED (NON-ROTORCRAFT RATED) PILOT WHO WAS WORKING ON HIS ROTORCRAFT RATING. THE HELICOPTER CRASHED IN A WOODED AREA WITH DEBRIS SPREAD ALONG THE FLIGHT PATH FOR OVER 1/4 MILE. POST CRASH EXAMINATION SHOWED THAT ONE STABILIZER BAR WAS MISSING FROM THE ROTOR HEAD AND HAD FAILED OPPOSITE THE DIRECTION OF ROTATION. THE STABILIZER BAR WAS NOT RECOVERED. THERE WAS EVIDENCE OF BLADE FLAPPING AND LOW ROTOR RPM CONDITIONS. NO EVIDENCE OF A FAILURE ON THE FLIGHT CONTROL SYSTEM, OTHER THAN THE MISSING STABILIZER CONTROL BAR WAS FOUND. NO EVIDENCE OF A ENGINE FAILURE WAS NOTED, ALTHOUGH CONDITIONS WERE PRESENT FOR THE FORMATION OF CARBURETOR ICE.
NTSB Probable Cause
A PILOT INDUCED LOW ROTOR RPM CONDITION, FOLLOWED BY BLADE FLAPPING AS THE MAIN ROTOR BLADE CONTACTED THE TAIL OF THE HELICOPTER.
Full Narrative
THE BELL 47D1 WAS ON A SOLO X-COUNTRY FLIGHT WITH A COMMERCIAL RATED (NON-ROTORCRAFT RATED) PILOT WHO WAS WORKING ON HIS ROTORCRAFT RATING. THE HELICOPTER CRASHED IN A WOODED AREA WITH DEBRIS SPREAD ALONG THE FLIGHT PATH FOR OVER 1/4 MILE. POST CRASH EXAMINATION SHOWED THAT ONE STABILIZER BAR WAS MISSING FROM THE ROTOR HEAD AND HAD FAILED OPPOSITE THE DIRECTION OF ROTATION. THE STABILIZER BAR WAS NOT RECOVERED. THERE WAS EVIDENCE OF BLADE FLAPPING AND LOW ROTOR RPM CONDITIONS. NO EVIDENCE OF A FAILURE ON THE FLIGHT CONTROL SYSTEM, OTHER THAN THE MISSING STABILIZER CONTROL BAR WAS FOUND. NO EVIDENCE OF A ENGINE FAILURE WAS NOTED, ALTHOUGH CONDITIONS WERE PRESENT FOR THE FORMATION OF CARBURETOR ICE.
Flight
Event TypeAccident
Event Time10:15 EST
Nearest Airport0nm N
Runway0
Runway Length0
Runway Width0
Flight Plan FiledNone
Aircraft FireNo
Aircraft ExplosionNo
Aircraft
AircraftBell 47D1
Tail NumberN163B
Aircraft CategoryHeli
DamageDestroyed
Operating RulePart 91
Engines1
Engine TypeReciprocating
Engine DetailsFranklin · 6V-335-A · Reciprocating · 200
Seats3
People & Injuries
Injury Summary1 injury (1 fatality)
Fatal1
Serious0
Minor0
Uninjured0
Total1
Crew 1Age 46 · Second Class
Conditions
ConditionsUnknown
LightDaylight
Wind300° @ 13 kt
Visibility35 sm
CeilingUnknown 3000 ft
Temperature / Dew Point32 C / 18 C
Altimeter30.00 inHg
Observation Time14:45
Weather SourceWIT