Accident Glasair GlaStar N4970Y,
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ASN Wikibase Occurrence # 146863
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Date:Sunday 22 July 2012
Type:Silhouette image of generic GLST model; specific model in this crash may look slightly different    
Glasair GlaStar
Registration: N4970Y
MSN: 5377
Total airframe hrs:1424 hours
Engine model:SUBARU Boxer 2.5L
Fatalities:Fatalities: 0 / Occupants: 1
Aircraft damage: Substantial
Location:Port District land north of Calumet Park, Chicago, IL -   United States of America
Phase: Landing
Departure airport:Osh Kosh, WI (OSH)
Destination airport:Benton Harbor, MI (BEH)
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
The pilot was on a cross-country flight in an experimental airplane when the engine began to “race.” The pilot tried to reduce power by adjusting the throttle, but the engine and propeller were unresponsive. He then made a forced landing to a soft field, and the airplane nosed over. Examination of the automotive engine revealed that the spline-shaft and adapter gears in the reduction gearbox were worn, which resulted in the gearbox's failure. According to the pilot, the gearbox was not a regularly inspected item for this particular engine/gearbox combination. At the time it failed, the gearbox had accrued 247 total hours since new.
Probable Cause: Failure of the automotive engine's reduction gearbox while in cruise flight.

Accident investigation:
Investigating agency: NTSB
Report number: CEN12LA470
Status: Investigation completed
Duration: 5 months
Download report: Final report



History of this aircraft

Other occurrences involving this aircraft
21 August 2005 N4970Y William Yomokoski 0 Marcellus, Michigan sub


Revision history:

22-Jul-2012 20:31 Geno Added
30-Jul-2012 04:13 gerard57 Updated [Damage]
21-Dec-2016 19:28 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]
27-Nov-2017 20:54 ASN Update Bot Updated [Operator, Other fatalities, Departure airport, Destination airport, Source, Narrative]

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