Mechanical & Engine Failure · NTSB WPR16LA050

MOORE ONEX — Fresno, CA

1 fatal
DateJanuary 10, 2016
LocationFresno, CA
AircraftMOORE ONEX (amateur-built)
Purpose of flightPersonal
ConditionsDay · Visual Meteorological Cond
Phase / occurrencePrior to flight Aircraft maintenance event
Pilot age70
Pilot total time484 hrs · Building experience
Time in typeUnknown
Fatalities1

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.

NTSB findings

  • Personnel issues-Task performance-Maintenance-Installation-Owner/builder - C
  • Personnel issues-Task performance-Use of equip/info-Aircraft control-Pilot - F
  • Personnel issues-Action/decision-Info processing/decision-Decision making/judgment-Pilot - F

What happened

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.

An editorial "what led to it / how to avoid it" analysis for this accident is generated separately and will appear here.

View the official NTSB docket →