Incident Overview
During the initial climb after takeoff, the pilot reported that the engine failed at approximately 100 to 200 feet above ground level. In response, the pilot executed a descending right turn to keep the aircraft within the airport boundary. The aircraft subsequently struck the ground.
Post-Accident Examination
An examination of the engine revealed that the upper portion of the magneto mount flange was broken. The magneto was hanging solely by its ignition wires. The upper flange exhibited a rectangular wear pattern, approximately 1/8 inch deep, corresponding to the mount block, and the flange had cracked away at that location. The lower mount block and its nut were missing. It appeared that either the bottom nut had been left off during installation or had vibrated off during operation.
Findings
The physical evidence indicated that the loss of magneto attachment likely resulted from the absence of the lower mount nut, which could have been due to improper installation or vibration-induced loosening.