Accident Sikorsky S-58E N70709,
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ASN Wikibase Occurrence # 380077
 
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Date:Monday 13 February 1984
Time:17:30 LT
Type:Silhouette image of generic S58P model; specific model in this crash may look slightly different    
Sikorsky S-58E
Owner/operator:Private
Registration: N70709
MSN: 145693
Engine model:WRIGHT R-1820-84
Fatalities:Fatalities: 0 / Occupants: 5
Aircraft damage: Substantial
Category:Accident
Location:Morgan City, LA -   United States of America
Phase: Taxi
Nature:Survey
Departure airport:
Destination airport:
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
THE HELICOPTER WAS HOVERING ABOVE TREES AT ABOUT 100 FT AGL WHEN THE TAIL ROTOR CHIP DETECTOR LGT FLICKERED SVRL TIMES, THEN ILLUMINATED STEADILY. THIS WAS FOLLOWED BY A LOUD GRINDING NOISE FROM THE TAIL AREA & THE ACFT YAWED TO THE RIGHT. THE ACFT ENTERED AN AUTOROTATION AFTER MAKING 3 TURNS TO THE RIGHT. IT DESCENDED INTO THE TREES AT WHICH TIME THE MAIN ROTOR BLADES WERE BROKEN OFF. AN EXAM OF THE INTERMEDIATE TAIL ROTOR GEAR BOX DISCLOSED THAT 6 TEETH IN THE INPUT BEVEL PINION GEAR, PN S1635-64114, HAD FAILED IN THE ROOT AREA. A METALLURGICAL EXAM DETERMINED THAT THE FAILURE ZONE HAD FATIGUE INDICATIONS. CRACKS WERE FOUND IN OTHER AREAS OF THE GEAR BOX. SIKORSKY ENGINEERS DETERMINED THAT THE GEAR BOX HAD BEEN SUBJECTED TO HEAVY LOADS. THE GEAR BOX HAD BEEN LAST OPENED IN 1968. ONE GEAR WAS NOT A SIKORSKY PRODUCT.

Probable Cause:

Accident investigation:
cover
  
Investigating agency: NTSB
Report number: FTW84LA136
Status: Investigation completed
Duration:
Download report: Final report

Sources:

NTSB FTW84LA136

Location

Revision history:

Date/timeContributorUpdates
01-Apr-2024 12:33 ASN Update Bot Added

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