What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
(-23) Aircraft in straight and level flight at approximately 1700 feet MSL when engine quit for unknown reason. Passenger tried to restart engine and was unnecessairly. Pilot made emergency landing in field. Aircraft hit rut in field and nose gear and left main collapsed. Left wing broke loose from rear mount and engine mount buckled firewall. Aircraft left smyrna airport mqy and landed at murfreesboro mbt, departed mbt and was in cruise flight of about 20 minutes when engine quit for reasons unknown. Engine tear down revealed that alternator drive gear had sheared and jammed accessory drive stopping engine. Alternator drive gear retaining nut did not have cotter pin locking device installed allowing nut to back off causing unit to jam and shear off then become lodged into accessory drive gears.
As the FAA filed it
(-23) AIRCRAFT IN STRAIGHT AND LEVEL FLIGHT AT APPROXIMATELY 1700 FEET MSL WHEN ENGINE QUIT FOR UNKNOWN REASON. PASSENGER TRIED TO RESTART ENGINE AND WAS UNNECESSAIRLY. PILOT MADE EMERGENCY LANDING IN FIELD. AIRCRAFT HIT RUT IN FIELD AND NOSE GEAR AND LEFT MAIN COLLAPSED. LEFT WING BROKE LOOSE FROM REAR MOUNT AND ENGINE MOUNT BUCKLED FIREWALL. AIRCRAFT LEFT SMYRNA AIRPORT MQY AND LANDED AT MURFREESBORO MBT, DEPARTED MBT AND WAS IN CRUISE FLIGHT OF ABOUT 20 MINUTES WHEN ENGINE QUIT FOR REASONS UNKNOWN. ENGINE TEAR DOWN REVEALED THAT ALTERNATOR DRIVE GEAR HAD SHEARED AND JAMMED ACCESSORY DRIVE STOPPING ENGINE. ALTERNATOR DRIVE GEAR RETAINING NUT DID NOT HAVE COTTER PIN LOCKING DEVICE INSTALLED ALLOWING NUT TO BACK OFF CAUSING UNIT TO JAM AND SHEAR OFF THEN BECOME LODGED INTO ACCESSORY DRIVE GEARS.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.