Connecting rod failure of an engine of a particular type of aircraft

One failed connecting rod along with other components of a an engine of an aircraft was sent to NAL for investigation. Failure investigation revealed that the fatigue fracture of the connecting rod No.3 was responsible for the engine failure. Visual, stereobinocular and microscopic examination suggest that friction at crank pin No.3 resulted in excessive bending stresses in the connecting rod leading to fatigue crack initiation at four corners of the web near the step at the big end. The most probable cause for the excessive friction at crank pin No.3 appears to be lubricant starvation, with subsequent overheating