ASN Wikibase Occurrence # 42441
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Date: | Saturday 20 August 1983 |
Time: | 10:05 |
Type: | Boeing Vertol 107-II (CH-46A) |
Owner/operator: | Columbia Helicopters |
Registration: | N190CH |
MSN: | 2002 |
Total airframe hrs: | 2392 hours |
Fatalities: | Fatalities: 2 / Occupants: 2 |
Aircraft damage: | Destroyed |
Category: | Accident |
Location: | Shaver Lake, CA -
United States of America
|
Phase: | En route |
Nature: | External load operation |
Departure airport: | Shaver Lake, CA |
Destination airport: | local |
Investigating agency: | NTSB |
Confidence Rating: | Accident investigation report completed and information captured |
Narrative:THE ONLY WITNESS, THE HOOKER, WHO GETS LOGS READY FOR TRANSPORT BY THE HELICOPTER, STATED THAT HE HEARD NOISES AND THE ROTOR BLADES BEGAN COMING APART AS THE ACFT STARTED DOWNHILL WITH A LOG. EXAMINATION OF THE WRECKAGE REVEALED THAT #3 SYCHRONIZING SHAFT (BOEING P/N 10703141-13) HAD FAILED A FATIGUE CRACK ORIGINATING AT A RIVET HOLE. THE TOTAL TIME ON THE SHAFT WAS 17492 HOURS WITH 435 HOURS SINCE OVERHAUL. THE QUALITY OF THE SURFACE FINISH ON THE RIVET HOLES WAS CONSIDERED UNSATISFACTORY IN A POST ACCIDENT LABORATORY EVALUATION. AS A INTERIM MEASURE BOEING VERTOL ARBITRAILY IMPOSED A LIFE OF 8750 HOURS ON ALL SYNCHRONIZING SHAFTS OF THIS TYPE. THIS WAS BASED ON THE LIFE OF THIS FAILED PART. A PROGRAM IS ALSO BEING DEVELOPED TO DO A FLT STRAIN SURVEY ON A BV-107 FOR LOGGING OPERATIONS. THE HOOKER STATED THAT THE LOG BEING LIFTED BY THE ACCIDENT ACFT WEIGHED BETWEEN 8000 AND 9000 POUNDS. CAUSE:
Sources:
http://www.ntsb.gov/ntsb/brief.asp?ev_id=20001214X44195 Revision history:
Date/time | Contributor | Updates |
24-Oct-2008 10:30 |
ASN archive |
Added |
10-Jan-2011 05:56 |
TB |
Updated [Time, Aircraft type, Operator, Other fatalities, Nature, Destination airport, Source] |
21-Dec-2016 19:24 |
ASN Update Bot |
Updated [Time, Damage, Category, Investigating agency] |
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