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NTSB Report
June 26, 1985 · Aerospatiale AS35OD · N148BH
Dallas, TX
Overview
Report Status
Preliminary report
Event Type
Accident
Date
June 26, 1985
Injury Outcomes
1 injury (1 fatality)
Location
Dallas, TX
Aircraft
Aerospatiale AS35OD
Tail Number
N148BH
Operator
Telstar Transports
Injuries
Fatal
Aircraft Damage
Destroyed
NTSB Number
FTW85FA265
THE ENG TO TRANSMISSION SHORT SHAFT BECAME DISCONNECTED IN FLT. THIS RESULTED IN COMPLETE LOSS OF PWR TO THE MAIN ROTOR ASSEMBLY. HOWEVER, THE TAIL ROTOR ASSEMBLY WAS STILL BEING POWERED BY THE ENG. UPON COLLECTIVE PITCH APPLICATION TO STOP THE DESCENT THE ACFT YAWED ABOUT 90 DEGS TO THE RIGHT AND ALSO ROLLED ABOUT 70 DEGS TO THE RIGHT AND IMPACTED THE TRUNK OF A LARGE TREE. THIS IMPACT RESULTED IN DISINTEGRATION OF THE HELICOPTER. INVESTIGATION REVEALED THAT COTTER PINS HAD NOT BEEN INSTALLED IN THE BOLTS WHICH CONNECT THE FORWARD END OF THE SHORT SHAFT TO THE FLEXIBLE COUPLING AT THE TRANSMISSION. IT ALSO REVEALED THAT A REQUIRED 30 HR RECURRING INSPECTION HAD NOT BEEN COMPLETED AND WAS 15.9 HRS OVERDUE. THE COMPLETION OF THIS REQUIRED INSPECTION WOULD HAVE REVEALED THAT THE COTTER PINS WERE MISSING.
Full Narrative
THE ENG TO TRANSMISSION SHORT SHAFT BECAME DISCONNECTED IN FLT. THIS RESULTED IN COMPLETE LOSS OF PWR TO THE MAIN ROTOR ASSEMBLY. HOWEVER, THE TAIL ROTOR ASSEMBLY WAS STILL BEING POWERED BY THE ENG. UPON COLLECTIVE PITCH APPLICATION TO STOP THE DESCENT THE ACFT YAWED ABOUT 90 DEGS TO THE RIGHT AND ALSO ROLLED ABOUT 70 DEGS TO THE RIGHT AND IMPACTED THE TRUNK OF A LARGE TREE. THIS IMPACT RESULTED IN DISINTEGRATION OF THE HELICOPTER. INVESTIGATION REVEALED THAT COTTER PINS HAD NOT BEEN INSTALLED IN THE BOLTS WHICH CONNECT THE FORWARD END OF THE SHORT SHAFT TO THE FLEXIBLE COUPLING AT THE TRANSMISSION. IT ALSO REVEALED THAT A REQUIRED 30 HR RECURRING INSPECTION HAD NOT BEEN COMPLETED AND WAS 15.9 HRS OVERDUE. THE COMPLETION OF THIS REQUIRED INSPECTION WOULD HAVE REVEALED THAT THE COTTER PINS WERE MISSING.
Flight
Event TypeAccident
Event Time11:40 CDT
Nearest Airport0nm N
Runway0
Runway Length0
Runway Width0
Flight Plan FiledNone
Aircraft FireNo
Aircraft ExplosionNo
Aircraft
AircraftAerospatiale AS35OD
Tail NumberN148BH
Aircraft CategoryHeli
DamageDestroyed
OperatorTelstar Transports
Operating RulePart 91
Engines1
Engine TypeTurboshaft
Engine DetailsLycoming · LTS-101-600A2 · Turboshaft · 531
Seats6
People & Injuries
Injury Summary1 injury (1 fatality)
Fatal1
Serious0
Minor0
Uninjured0
Total1
Crew 1Age 41 · Second Class
Conditions
ConditionsVMC
LightDaylight
Wind180° @ 14 kt
Visibility15 sm
CeilingBroken clouds 3000 ft
Temperature / Dew Point68 F
Altimeter29.00 inHg
Observation Time16:47
Weather SourceWFAC