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NTSB Report
September 14, 1983 · Sikorsky S-76A · N521AC
Chicago, IL
Overview
Report Status
Preliminary report
Event Type
Accident
Date
September 14, 1983
Injury Outcomes
3 injuries (3 minor injuries), 3 uninjured
Location
Chicago, IL
Aircraft
Sikorsky S-76A
Tail Number
N521AC
Injuries
Minor
Aircraft Damage
Destroyed
NTSB Number
CHI83FA428
WHILE CRUISING AT 2000 FT MSL & 150 KTS, THE CREW HEARD A LOUD NOISE, AND SIMULTANEOUSLY, THE HELICOPTER YAWED APRX 30 TO 40 DEG TO THE RIGHT & PITCHED NOSE DOWN. THE AIRCREW BEGAN AN AUTOROTATION & ACTIVATED THE EMERGENCY FLOATS. THE HELICOPTER CONTINUED IN A RIGHT DESCENDING TURN DURING THE AUTOROTATION. TOUCHDOWN IN THE WATER (LAKE MICHIGAN) OCCURRED WITH A FORWARD SPEED OF ABOUT 40 TO 50 KTS. AFTER CONTACTING THE WATER, THE HELICOPTER TURNED AN ADDITIONAL 180 DEG, THEN LISTED ABOUT 10 DEG TO THE LEFT. THE OCCUPANTS DONNED THEIR LIFE VESTS & EXITED THE HELICOPTER. ABOUT 11 TO 13 MINUTES AFTER LANDING, THE ACFT ROLLED OVER IN THE WATER & EVENTUALLY SUNK. THE OCCUPANTS WERE RESCUED BEFORE THE HELICOPTER SANK. AN INVESTIGATION REVEALED THAT THE LEFT SIDE TAIL ROTOR CABLE. PN 76400-03191-043, HAD FAILED WHERE IT HAD BEEN RUBBING. THE RUBBING WAS ATTRIBUTED TO INCORRECT ROUTING OF THE CABLE.
Full Narrative
WHILE CRUISING AT 2000 FT MSL & 150 KTS, THE CREW HEARD A LOUD NOISE, AND SIMULTANEOUSLY, THE HELICOPTER YAWED APRX 30 TO 40 DEG TO THE RIGHT & PITCHED NOSE DOWN. THE AIRCREW BEGAN AN AUTOROTATION & ACTIVATED THE EMERGENCY FLOATS. THE HELICOPTER CONTINUED IN A RIGHT DESCENDING TURN DURING THE AUTOROTATION. TOUCHDOWN IN THE WATER (LAKE MICHIGAN) OCCURRED WITH A FORWARD SPEED OF ABOUT 40 TO 50 KTS. AFTER CONTACTING THE WATER, THE HELICOPTER TURNED AN ADDITIONAL 180 DEG, THEN LISTED ABOUT 10 DEG TO THE LEFT. THE OCCUPANTS DONNED THEIR LIFE VESTS & EXITED THE HELICOPTER. ABOUT 11 TO 13 MINUTES AFTER LANDING, THE ACFT ROLLED OVER IN THE WATER & EVENTUALLY SUNK. THE OCCUPANTS WERE RESCUED BEFORE THE HELICOPTER SANK. AN INVESTIGATION REVEALED THAT THE LEFT SIDE TAIL ROTOR CABLE. PN 76400-03191-043, HAD FAILED WHERE IT HAD BEEN RUBBING. THE RUBBING WAS ATTRIBUTED TO INCORRECT ROUTING OF THE CABLE.
Flight
Event TypeAccident
Event Time18:23 CDT
Nearest Airport0nm N
Runway0
Flight Plan FiledNone
Aircraft FireNo
Aircraft ExplosionNo
Aircraft
AircraftSikorsky S-76A
Tail NumberN521AC
Aircraft CategoryHeli
DamageDestroyed
Operating RulePart 91
Engines2
Engine TypeTurboshaft
Engine DetailsAllison · 250-C30 · Turboshaft · 969
Seats7
People & Injuries
Injury Summary3 injuries (3 minor injuries), 3 uninjured
Fatal0
Serious0
Minor3
Uninjured3
Total6
Crew 1Age 29 · Second Class
Conditions
ConditionsVMC
LightDaylight
Wind360° @ 10 kt
Visibility20 sm
CeilingNone
Temperature / Dew Point68 F / 0 C
Altimeter30.00 inHg
Weather SourcePILO