Amateur-built CH 701 N75644 accident near Murfreesboro, Tennessee

Probable cause

A total loss of engine power due to the improper installation of the alternator drive gear.

NTSB analysis

According to the pilot of the experimental amateur-built airplane, about 15 minutes after departing the airport, and while flying approximately 1,000 feet above ground level, the engine lost power. The pilot immediately established the airplane in a glide, and began looking for a suitable landing site. He asked the passenger to attempt an engine restart, but the passenger was not successful. The pilot subsequently performed a forced landing to a pasture, which caused the nose landing gear to buckle and resulted in substantial damage to the airframe. Postaccident examination of the engine revealed that the alternator drive gear had sheared and jammed the accessory drive gears. Additionally, the alternator drive gear retaining nut did not have a cotter pin locking device installed, likely allowing the nut to back off. The airframe had accumulated 43 total hours since being assembled and the engine had accumulated 46 total hours since the most recent overhaul.

Text from the NTSB. Open the NTSB docket for ERA09LA446 for the full record.