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NTSB Report
June 4, 1988 · Fairchild Hiller FH-1100 · N53EP
Lihue, HI
Overview
Report Status
Probable Cause
Event Type
Accident
Date
June 4, 1988
Injury Outcomes
No injuries (5 uninjured)
Location
Lihue, HI
Aircraft
Fairchild Hiller FH-1100
Tail Number
N53EP
Operator
Safari Helicopters Tours
Injuries
None
Aircraft Damage
Substantial
NTSB Number
LAX88LA212
THE PILOT SAID THAT THE AIRCRAFT WAS IN NORMAL CRUISE FLIGHT WHEN HE NOTICED THAT THE ENGINE WAS NO LONGER DRIVING THE ROTOR SYSTEM. THE PILOT ENTERED AN AUTOROTATION AND HAD TO STRETCH THE GLIDE SLIGHTLY TO A SUITABLE LANDING AREA ON AN OFF SHORE REEF. THE HELICOPTER MADE A HARD LANDING ON THE REEF IN ABOUT ONE FOOT OF WATER. ON SITE EXAMINATION OF THE HELICOPTER BY FAA AIRWORTHINESS INSPECTORS REVEALED THAT THE BENDIX COUPLING ON THE ENGINE TO TRANSMISSION SHAFT HAD RUPTURED ON THE ENGINE END OF THE SHAFT. METALLURGICAL EXAMINATION OF THE FAILED COUPLING REVEALED A FATIGUE FRACTURE IN A CIRCUMFERENTIAL ORIENTATION ON THE COUPLING DISK. THE DRIVE SHAFT COUPLINGS ARE THE SUBJECT OF A RECURRING AD WHICH MANDATES ALIGNMENT MEASUREMENTS OF THE DRIVE SHAFT EVERY 100 HOURS. THE LAST ALIGNMENT CHECK WAS DONE ABOUT 60 HOURS PRIOR TO THE ACCIDENT.
NTSB Probable Cause
FATIGUE FAILURE OF THE ENGINE TO TRANSMISSION DRIVE SHAFT ENGINE COUPLING DUE TO AN ANGULAR MISALIGNMENT OF THE DRIVE SHAFT.
Full Narrative
THE PILOT SAID THAT THE AIRCRAFT WAS IN NORMAL CRUISE FLIGHT WHEN HE NOTICED THAT THE ENGINE WAS NO LONGER DRIVING THE ROTOR SYSTEM. THE PILOT ENTERED AN AUTOROTATION AND HAD TO STRETCH THE GLIDE SLIGHTLY TO A SUITABLE LANDING AREA ON AN OFF SHORE REEF. THE HELICOPTER MADE A HARD LANDING ON THE REEF IN ABOUT ONE FOOT OF WATER. ON SITE EXAMINATION OF THE HELICOPTER BY FAA AIRWORTHINESS INSPECTORS REVEALED THAT THE BENDIX COUPLING ON THE ENGINE TO TRANSMISSION SHAFT HAD RUPTURED ON THE ENGINE END OF THE SHAFT. METALLURGICAL EXAMINATION OF THE FAILED COUPLING REVEALED A FATIGUE FRACTURE IN A CIRCUMFERENTIAL ORIENTATION ON THE COUPLING DISK. THE DRIVE SHAFT COUPLINGS ARE THE SUBJECT OF A RECURRING AD WHICH MANDATES ALIGNMENT MEASUREMENTS OF THE DRIVE SHAFT EVERY 100 HOURS. THE LAST ALIGNMENT CHECK WAS DONE ABOUT 60 HOURS PRIOR TO THE ACCIDENT.
Flight
Event TypeAccident
Event Time12:00 HST
Nearest Airport0nm N
Runway0
Runway Length0
Runway Width0
Flight Plan FiledNone
Aircraft FireNo
Aircraft ExplosionNo
Aircraft
AircraftFairchild Hiller FH-1100
Tail NumberN53EP
Aircraft CategoryHeli
DamageSubstantial
OperatorSafari Helicopters Tours
Operating RulePart 91
Engines1
Engine TypeTurboshaft
Engine DetailsAllison · 250-C18C · Turboshaft · 274
Seats5
People & Injuries
Injury SummaryNo injuries (5 uninjured)
Fatal0
Serious0
Minor0
Uninjured5
Total5
Crew 1Age 40 · Second Class
Conditions
ConditionsVMC
LightDaylight
Wind90° @ 14 kt
Visibility15 sm
CeilingNone
Temperature / Dew Point0 C
Altimeter0
Weather SourcePILO