Amateur-built Long-EZE SR7-1 N97EZ accident near Falfurrias, Texas

Probable cause

A total loss of engine power due to a failure of the crankshaft behind the No. 3 connecting rod journal for undetermined reasons.

NTSB analysis

The pilot reported that he was in level cruise flight at 3,500 feet mean sea level when the engine suddenly vibrated then seized. The pilot made a "firm" forced landing on rolling brush and rock-strewn terrain. During the landing roll, the landing gear was sheared off and the canard wing was crushed. Engine disassembly revealed case fretting and main bearing movement. A representative of the engine manufacturer indicated that the failure mode was extremely rare, if not unique. The pilot had installed a Hertzler “Silver Bullet” composite propeller to the extended hub. According to the representative, it was possible that a harmonic vibration could have emanated from the propeller through the extended hub to the crankshaft. However, this propeller had not been tested to determine if there were amplified propeller harmonics to the crankshaft and the investigation was unable to determine that such vibration led to the engine failure.

Text from the NTSB. Open the NTSB docket for CEN10LA131 for the full record.