Accident Sonex Onex N1950J,
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ASN Wikibase Occurrence # 183397
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Date:Sunday 10 January 2016
Type:Sonex Onex
Registration: N1950J
MSN: ONX0118
Year of manufacture:2011
Total airframe hrs:0 hours
Engine model:VW Type 1VW
Fatalities:Fatalities: 1 / Occupants: 1
Aircraft damage: Substantial
Location:Fresno Chandler Executive Airport (KFCH), Fresno, CA -   United States of America
Phase: Take off
Departure airport:Fresno, CA (FCH)
Destination airport:Fresno, CA (FCH)
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
The pilot/builder was carrying out the initial flight test after recently building the amateur experimental airplane. Shortly after takeoff, the airplane's engine experienced a total power loss and the pilot initiated a descending left turn in order to avoid an airport fence. Subsequently, the airplane impacted terrain, in a nose down attitude with the left wing low.

An examination of the engine revealed that the Force One Main Bearing seized to the crankshaft. Further, there were multiple circular impressions on the bearing surface. Based on this evidence, it is likely that while building the experimental engine, the pilot did not properly align the Force One Main Bearing, and the oil feed hole was inadvertently used as the dowel pin hole, which resulted in a blockage of the oil transfer hole, thus preventing oil into the bearing and resulted in engine seizure and total power loss.

Probable Cause: The pilot/builder's failure to properly align the Force One Main Bearing, which resulted in a blockage of the oil transfer hole and culminated with a total engine power loss. Contributing to the accident was the pilot's failure to arrest the bank and sink rate prior to impact.

Accident investigation:
Investigating agency: NTSB
Report number: WPR16LA050
Status: Investigation completed
Duration: 2 years
Download report: Final report


FAA register:


Revision history:

11-Jan-2016 06:18 Geno Added
11-Jan-2016 16:30 Geno Updated [Aircraft type, Registration, Cn, Operator, Source, Damage, Narrative]
21-Dec-2016 19:30 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]
07-Feb-2018 13:48 ASN Update Bot Updated [Time, Total fatalities, Nature, Departure airport, Destination airport, Source, Narrative]

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