Pilot Report
During a pull-up maneuver, the pilot observed that the propeller transitioned to a low pitch angle and the engine was not producing full power. The tachometer indicated near the red line, prompting the pilot to retard the propeller pitch control and throttle. The oil pressure gauge showed normal readings.
Believing that sufficient power remained to reach the edge of the field, the pilot intended to dump the load to minimize crop damage. However, the aircraft lacked the power to clear a line of trees. Consequently, a forced landing was executed in the trees, resulting in damage to the aircraft.
Mechanical Findings
Examination of the engine revealed that the number six connecting rod had failed approximately one inch from the rod cap. Localized overheating was evident on the rod. The number six rod received oil via splash and spray from an oil port in the main journal. The main journal bearing had apparently spun, closing off the oil port and reducing the supply of cooling oil to the number six rod.
The propeller governor also received oil from the same port. Obstruction of oil flow to the governor would allow the propeller to move to a low pitch and high RPM position, consistent with the pilot's report.