ASN Wikibase Occurrence # 202068
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Date: | Wednesday 10 March 1999 |
Time: | 10:10 LT |
Type: | Schweizer 269C |
Owner/operator: | Smith Helicopters, Inc. |
Registration: | N36254 |
MSN: | S1186 |
Total airframe hrs: | 3367 hours |
Engine model: | Lycoming HIO-360-DIA |
Fatalities: | Fatalities: 0 / Occupants: 2 |
Aircraft damage: | Substantial |
Category: | Accident |
Location: | Laredo, TX -
United States of America
|
Phase: | Taxi |
Nature: | Executive |
Departure airport: | (NONE) |
Destination airport: | |
Investigating agency: | NTSB |
Confidence Rating: | Accident investigation report completed and information captured |
Narrative:The helicopter was at a 50-foot hover over a creek when the pilot heard a loud banging, followed by a loss of engine power. The pilot executed a right pedal turn and set the helicopter down hard in a creek. Examination of the engine revealed that the crankshaft was separated at the number 3 main bearing journal to number 3 connecting rod journal crossover cheek. A magnaflux examination of the crankshaft revealed that the number 3 main bearing journal displayed lateral cracks. Examination of the crankshaft fracture surfaces revealed that the crankshaft had failed in fatigue. The fracture features were damaged near the origin area; however, 'nearby crack arrest positions clearly indicated crack initiation from at least two locations on the journal surface near the crank cheek.' Examination of the number 3 bearing shell halves revealed that 'one shell had shifted relative to the other when the damage occurred.'
Probable Cause: The loss of engine power due to a bearing shift, which resulted in fatigue cracking of the crankshaft and subsequent failure of the crankshaft. A factor was a lack of suitable terrain for the forced landing.
Accident investigation:
|
| |
Investigating agency: | NTSB |
Report number: | FTW99LA092 |
Status: | Investigation completed |
Duration: | 1 year and 9 months |
Download report: | Final report |
|
Sources:
NTSB FTW99LA092
Location
Revision history:
Date/time | Contributor | Updates |
26-Nov-2017 10:55 |
ASN Update Bot |
Added |
08-Apr-2024 08:53 |
ASN Update Bot |
Updated [Time, Other fatalities, Phase, Departure airport, Source, Narrative, Category, Accident report] |
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