What happened
During the climb phase following takeoff, the pilot of the aircraft experienced a noticeable change in engine operation. Although the oil pressure and oil temperature gauges initially showed normal readings, the engine RPM briefly spiked beyond the redline before dropping to a lower level. The pilot attempted to divert to the nearest airport, but reported that a mechanical failure occurred within the engine, causing the yoke to vibrate. Shortly thereafter, oil began to splatter onto the windshield.
As the propeller continued to rotate, the aircraft was unable to maintain altitude. The pilot was forced to glide the aircraft until it impacted trees and entered a swamp. There were no injuries reported in the accident.
The investigation
Mechanical examination of the engine revealed cracks and a hole in the top of the crankcase. Investigators found that the No. 5 connecting rod cap had separated, with fragments of the rod cap and bolts located within the engine sump. Due to extensive mechanical damage, the fracture features of the rod cap and bolts could not be clearly analyzed.
No evidence of oil leakage was found at the propeller hub or any engine seals. Records indicated that the connecting rods had been replaced during a major overhaul on July 13, 1992. Additionally, a new McCauley propeller had been installed on April 14, 2005, following an annual inspection. At the time of the accident, the engine had accumulated 1,141.2 hours since its last major overhaul and only 9 hours since the most recent annual inspection.