Incident Description
Shortly after takeoff, at approximately 100 feet altitude, witnesses heard the engine sputter and lose power. The aircraft was then observed to bank steeply to the left and descend into trees, where a postcrash fire erupted.
Examination Findings
The investigation revealed that the No. 3 connecting rod had failed due to fatigue. The fatigue crack originated from galling marks in the bearing area on the end of the crankshaft. According to Lycoming Engines, galling is caused by engine overspeed or overboost. No records were found indicating that such events had occurred.
After separation, the connecting rod jammed into the engine case but did not hinder engine rotation. The propeller exhibited rotational damage, and the blade angle at impact was consistent with an engine speed in the 2100 RPM range. Several large tree limbs were found cut by the propeller at the crash site.