CUSTER, SD, USA
N150C
STINSON 108-2
THE PRIVATE PLT WAS PERFORMING A FLIGHT FOLLOWING HIS INSTALLATION OF TWO MAGNETOS. A WITNESS AND THE PLT REPORTED THAT ON CLIMB OUT THE ENGINE QUIT. THE PLT SAID HE HEARD SOMETHING BREAK IN THE ENGINE. THE PLT ATTEMPTED TO LAND ON A GRAVEL DRIVEWAY SOUTH OF THE RUNWAY. AT IMPACT, THE MAIN LANDING GEAR COLLAPSED. THE PLANE CAME TO REST AFTER SLIDING 150 FT. A POST ACCIDENT INSPECTION REVEALED THAT BOTH MAGNETOS HAD BEEN INSTALLED WITHOUT COTTER PINS ON THE DRIVE GEAR RETAINING NUTS. THIS RESULTED IN THE NUTS BACKING OFF, DISCONNECTING THE MAGNETOS, AND ONE OF THE GEARS FALLING INTO THE ENGINE, RESULTING IN THE REPORTED STOPPAGE.
THE IMPROPER MAINTENANCE BY THE PILOT IN COMMAND/OWNER IN THAT THE MAGNETO DRIVE GEAR RETAINING NUTS WERE NOT SAFETIED WHICH RESULTED IN THEM BACKING OFF, DISCONNECTING THE MAGNETOES AND ONE OF THE GEARS FALLING INTO THE ENGINE.
Source: NTSB Aviation Accident Database
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