Accident Sikorsky S-76A N50KY,
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ASN Wikibase Occurrence # 74751
 
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Date:Friday 7 August 1992
Time:12:10 LT
Type:Silhouette image of generic S76 model; specific model in this crash may look slightly different    
Sikorsky S-76A
Owner/operator:Commonwealth Of Kentuky
Registration: N50KY
MSN: 760059
Year of manufacture:1980
Total airframe hrs:3950 hours
Engine model:ALLISON 250-C30
Fatalities:Fatalities: 0 / Occupants: 6
Aircraft damage: Destroyed
Category:Accident
Location:Graefenburg, KY -   United States of America
Phase: En route
Nature:Unknown
Departure airport:Frankfort, KY (KFFT)
Destination airport:Ft Knox, KY (KFTK)
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
BEFORE FLT, THE COPLT BGN A PREFLT INSPN, & SUBSEQUENTLY, THE HELICOPTER WAS MVD FM THE HANGAR TO THE TERMINAL, WHERE A WITNESS OBSERVED THE ENG COWLING OPEN. THE PLT ALSO MADE A WALKAROUND VISUAL INSPN OF THE HELICOPTER BFR FLT. NEITHER OF THE FLTCREW NOTED ANY DISCREPANCY. ABT 1 MIN & 40 SEC AFTER TAKEOFF, THE FLT CREW HEARD A NOISE, FLWD BY LOSS OF DRCTNL CTL; 3 OF THE PSGRS NOTED THE ODOR OF SOMETHING OVERHEATING. AN AUTOROTATION & LANDING WERE MADE ON HILLY TRRN, WHERE THE HELICOPTER CAME TO REST IN A RAVINE AGAINST A TREE. DRG AN EXAM, THE 2 LEFT SIDE ENG COWLING LATCHES WERE FND OPEN; ALSO, THE LEFT SIDE OF THE AFT ENG COWLING WAS OPEN. THERE WAS EVIDENCE THAT DURING FLT, THE LEFT SIDE OF THE COWLING CONTACTED THE MAIN ROTOR BLADES; THE COWLING THEN MADE CONTACT WITH SECTION II OF THE TAIL ROTOR DRIVESHAFT. FRICTION BTN THE COWLING & THE DRIVESHAFT RESULTED IN LOCALIZED HIGH TEMPERATURE & THE TAIL ROTOR SHAFT FAILED AT THAT LOCATION. ONE OF THE 4 TAIL ROTOR BLADES SEPARATED DURING THE OCCURRENCE.

Probable Cause: AN INADEQUATE PREFLIGHT INSPECTION BY THE FLIGHT CREW BY FAILING TO ASSURE THAT ALL FOUR OF THE ENGINE COWLING LATCHES WERE PROPERLY SECURED, WHICH RESULTED IN SUBSEQUENT FAILURE OF SECTION II OF THE TAIL ROTOR DRIVESHAFT AFTER THE COWLING CONTACTED THE MAIN ROTOR BLADES AND TAIL ROTOR DRIVESHAFT.

Accident investigation:
cover
  
Investigating agency: NTSB
Report number: NYC92GA147
Status: Investigation completed
Duration: 1 year 1 month
Download report: Final report

Sources:

NTSB NYC92GA147

Location

Revision history:

Date/timeContributorUpdates
12-Jun-2010 09:26 TB Added
21-Dec-2016 19:25 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]
10-Apr-2024 18:54 ASN Update Bot Updated [Time, Operator, Other fatalities, Phase, Departure airport, Destination airport, Source, Narrative, Category, Accident report]

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